XCVario Pur User Manual

XCVario 57mm and 80mm

Series: XCV-20 and upward

Software Version: XCVario Pur latest

Manual edition 2.0.X
info@xcvario.com

General

XCVario Pur Edition – Next-Generation Smart Variometer

The XCVario Pur edition is a digital variometer with wired and wireless interfaces for XCSoar, LK8000, OpenVario, Naviter and compatible systems.
It uses high-resolution, temperature-compensated sensors for pressure, acceleration and temperature. Both TE-probe compensation and electronic TE are supported. Audio output is provided via an integrated speaker.
A Kalman filter is used for climb rate estimation, providing fast response with reduced noise. Load-factor-based polar correction (g-compensation) improves netto variometer accuracy during dynamic flight conditions.
The FLARM/NMEA interface allows task declaration, configuration and flight log download via XCSoar.

The system provides

• Variometer indication
• Airspeed indication
• Altitude indication
• Wind estimation
• Battery status
• Outside Air Temperature
• Flap control assistance
• Polar library with more than 150 glider polars
• WiFi, Bluetooth, Serial line interfaces with automated routing

Sensor precision and accuracy.

Thanks to the high resolution of the digital, temperature-compensated and factory-calibrated pressure sensors, even the smallest height differences of just 8 cm are detected. Properties such as accuracy, reliability and long-term stability are therefore given. The sensor for the dynamic pressure or speed or IAS enables an absolute accuracy of better than 1%, at 100 km/h the deviation is a maximum of 1 km/h.
The outside temperature can be measured with the digital temperature sensor with a resolution of 0.1° Celsius. It is included in the calculation of the TAS (True Airspeed) as an atmospheric parameter for determining the air density.

Human interface design

The new XCVario Pure marks a significant step forward in electronic variometer design. Its completely redesigned visual interface, combined with a new generation of audio feedback, provides a more intuitive and immediate connection between the pilot and the aircraft.
This manual introduces the new concept and shows how to get the most out of XCVario Pure’s enhanced visual and acoustic assistance.

Pur Version Features

Key Features

• 270° clear variometer display, ±5 m/s (range configurable), high readability
• Fast, low-noise climb indication using smart Kalman filtering
• Load-factor-based polar correction (g-compensation) for accurate netto vario
• Speed-to-fly (STF) indication with command arrows
• Integrated speaker with configurable audio profiles and warning tones
• FLARM alarm screen with wind corrected heading of traffic
• Seamless FLARM integration (task declaration, configuration, flight download from XCSoar)
• Simplified setup with automatic data routing (wireless, S1, S2)
• Bright, high-contrast IPS display, sunlight readable
• Stable wind calculation in circling flight (extended with compass support, in future release)
• Flap assistant with dynamic recommendations (ballast, speed, load factor)

General Functions

• Barometric altimeter with QNH setting or automatic QNH (airfield altitude)
• Speed display: IAS, TAS
• Adjustable MacCready, water-ballast and bugs settings
• Stall warning
• Outside air temperature (OAT) via digital sensor
• Battery status display with configurable voltage thresholds
• Extensive polar library (>150 glider polars), editable speed polar
• Compass Heading (with magnetic sensor)

Audio

• Configurable vario sound (frequency, chopping, dual tone, deadband)
• Multi-spectrum variotone with adjustable harmonics
• Distinct audio warnings (stall, overload, gear, FLARM)
• Multiple audio profiles (aligned with common variometer sounds)

Interfaces

• Wireless: Bluetooth (Classic und BLE) or WiFi access point
• 2 × RS232 (TTL level), S1 Flarm and S2 in IGC standard
• CAN bus interface (e.g. second seat device, and or magnetic sensor)
• FLARM bridge (IGC FLARM, configuration and data exchange)
• Inputs for flap sensor or landing gear warning

Sensors and Systems

• AHRS (6-axis: 3-axis gyroscope, 3-axis accelerometer)
• Optional digital compass (external sensor)
• Temperature stabilization for AHRS for improved long-term accuracy

User Interface

• Rotary encoder with push function and progressive acceleration
• Streamlined setup menu with reduced submenu depth
• Inline configuration pages
• Quick exit from menus via long press
• Context-sensitive setup hints
• Auto-timeout to main screen after 16 s in flight
• Persistent warnings during setup
• Bottom-screen message area for alerts
• Clean overlay display for FLARM warnings
• Rotating FLARM view aligned with aircraft attitude, respecting the wind correction angle
• Improved variometer readability

Flight Functions

• Flap assistant (configurable, with external sensor)
• Optional landing gear warning via shared input
• Wind calculation, including the display of external wind (anemoi)
• Ballast reminder from previous flight
• Improved automatic STF switching with selectable delay
• Instant response to external STF switch
• Thermal assistant with enlarged, clearer display

Hardware

• Integrated speaker
• Compact design for standard 57 mm or 80 mm panel cut-outs
• Housing depth: 35 mm
• Strong aluminum enclosure, matte black (low EMI, shielding)
• Low power consumption, typical 100 mA at 12V

System

• Software update via WiFi data connection
• Interface reconfiguration on-the-fly
• Automatic CAN device detection (e.g. sensors, peripherals)
• Improved boot logic with instant availability of the variometer

The following system overview shows how the XCVario Pur integrates into a modern cockpit environment.

A typical configuration uses an Android device running XCSoar connected via Classic Bluetooth, or Naviter SeeYou Mobile connected via Bluetooth Low Energy (BLE) to the wireless interface. A FLARM device is connected to Interface S1 via cable.
In the Pur version, external devices are configured in a single, streamlined dialog. All data routing between wireless interfaces, S1, and S2 is handled automatically. XCSoar instantly receives Vario, GPS, FLARM, and other sensor data—regardless of where devices are connected—without any manual routing configuration.
The wireless interface ensuring stable, low-latency communication with modern Android devices.
WiFi is also available enabling control of an additional device on Interface S2, such as a radio or navigation unit.
The Pur firmware further adds Auto-Connect logic for CAN-based devices (MagSens rev.1, Jumbo), and serial configuration changes take effect instantly without requiring a reboot.

XCVario Pur – Operation Overview

The operation of the XCVario Pur is simple, intuitive, and optimized for both beginners and advanced pilots. Control is primarily via the rotary knob with integrated push function, complemented by an optional additional switch or button (configurable) for Vario or speed command mode, and the main on-off switch. The following description refers to the default configuration; all rotary functions can be customized during setup (see Setup chapter).

Switching On and Initial Setup

1. After switching on (still on ground), first set the QNH with the rotary knob. Set the airfield elevation will skip this step and the QNH will be set automatically. Then press the rotary knob to start the variometer display screen
2. Rotate the knob to the left to decrease volume, or to the right to increase it.

Accessing Menus and Settings

• Pressing the rotary knob once advances the screen through the list of available screens. As a minimum XCVario provides the variometer and the setup screen. A long-button-press always and directly enters the setup menu. This is the place where parameters such as MacCready (MC) value, water-ballast, polar, and more can be adjusted.
• The heading of the very first setup menu shows the configured glider polar type.
• Turn the rotary to scroll down or up through menu items.
• Nested menus allow you to dive deeper by pressing the rotary, the top item of each sub-menu returns you to the previous level.
• A long-button-press on a top row entry [< … ] the setup menu exits straight away. While airborn a time-out of 16 seconds will leaf the setup without any user interaction.

Adjusting and Saving Values

• Almost all setup items include integrated help texts for quick guidance, even for new users.
• Turn left to decrease and right to increase any configuration value.
• Confirm and save a value with a simple push; the device will acknowledge with “save” and return to the previous screen or dialog.
• Certain parameters, such as the MC value, return directly to the variometer display after setting, eliminating the need to press additional buttons.

An important feature of the XCVario Pur is system management via the device’s integrated WiFi access point. To activate the web interface, enable the XCVario WiFi under:

System → Software → Start Webserver.

Once WiFi is activated on the XCVario, you can connect to the “XCVario OTA” access point. After a successful connection, the XCVario management page can be accessed by navigating to:

https://192.168.4.1

in your web browser. On this page, you will find:

• Software Update – update the device firmware easily over the air.
• Debug / Reset – perform a factory reset (see the separate chapter under “Setup”) or access a core file for debugging purposes.
• Backup / Restore – create a backup of your current configuration on a mobile device, tablet, or laptop, and restore it back to the XCVario Pur when needed.

This system allows for easy maintenance, troubleshooting, and configuration management without the need for physical connections or additional software.

Software Update

Under the Software Update tab, the currently installed software version is displayed, along with details such as the exact build time of the package. Using [SELECT], you can choose a new software file on your smartphone, tablet, or PC, and then upload it to the device via [UPLOAD].

Debug/Reset

The operation is straightforward. After pressing the [FACTORY RESET] button, you must confirm the action in a separate dialog. The device will then be reset to factory settings. All user settings will be lost unless a backup of the configuration has been created (see the next section).

The [DOWNLOAD CORE DUMP] button generates a file that can be sent to the manufacturer for troubleshooting if the device experiences malfunctions during operation—for example, when using new features still in alpha (test) mode. The core dump is created only if the system encounters a fatal error and the software restarts. Once uploaded to the XCVario, the core file is automatically deleted.

Backup/Restore

The operation is intuitive. The [BACKUP] button saves all settings that differ from the factory defaults—including compass calibration and any deviation tables—into a file that can be stored on a mobile phone, tablet, or PC.

The [RESTORE] button loads a previously saved configuration file back into the device. This is especially useful when replacing a device, upgrading to a newer model, or after performing a factory reset. By default, the restore process does not perform a factory reset, meaning any settings not included in the backup remain unchanged. If you want to apply only the settings from the backup, a factory reset must be performed beforehand.

This approach provides flexibility: you can either completely restore the device to a previous state or merge the backup with the existing configuration.

Variometer Display

The XCVario Pur variometer retains the familiar round-instrument style, providing a clear and intuitive representation of climb and sink rates. It offers three primary display modes—Gross, Net, and Super-Net—which take polar sink into account differently depending on flight conditions. Gross mode, normally used while circling, shows actual climb, while Net mode incorporates the polar sink into the pointer for more accurate cruising information and Super-Net mode additionally adjusts for polar sink of circling flight, predicting effective climb regardless of current speed.

The central part of the display shows the integrated climb (last 20 seconds) in the selected units, and optionally, the smart flap assistant can be displayed based on current airspeed for flap type gliders. Speed-to-fly guidance is visualized using colored bars, indicating whether to fly faster or slower. The MacCready (MC) value is shown prominently, making it easy to read at a glance.

The XCVario Pur is configurable. Pilots can adjust the variometer range (3-7 m/s), units (metric or imperial), and display scaling (linear or logarithmic). Additional information includes average climb trends, visualized with a dot indicating improvement (green) or deterioration (red), wind direction and speed, altimeter readings (full resolution or quantized to 10 m), and temperature.

Mean Climb

The mean climb is represented as a colored dot within the variometer scale, which moves up or down according to the current climb rate. Climb values that are too low—such as periods spent searching for thermals—are excluded from the core climb calculation. This ensures that the mean climb reflects the most relevant performance and provides the best possible suggestion for the MacCready value.

Left upper corner

The left upper corner on display can be configured to various values such as IAS, TAS, GND Speed, Speed2Fly, Mc Value, Net Vario, OAT, Heading, Slip Angle, or been disabled at all. Above you see an example for IAS and OAT.

Left lower Corner

The current altitude together with the associated QNH or QFE setting is being displayed in form of a rolling tape. Altitude can be displayed in meters, feet or even flight level (FL). As an alternative there is a wind arrow indicating the direction the wind is coming from together with the speed in digital format.

Vario or Cruise Speed to Fly Indicator

In circling mode, a circular arrow is displayed on the right side and in cruise mode the S2F command arrows are displayed. The arrows point up to indicate slower and down for faster cruise speed. If the deviation is more than 40 km/h, the arrows tip turns white. If the cruise speed is well in a range of +/- 10 km/h off, the middle bar turns green. The number of arrows corresponds to the speed to fly difference. The arrows can display +/-30 km/h difference, each segment stands for 10 km/h off.

Smart Flap Assistant

Once enabled, on the right side of the display you see the smart flap assistant, giving recommendations to positioning the flaps. Optimum flap positioning is achieved when the moving green speed band overlaps with the middle section. The flap level displayed in the middle is either the level read from the flap sensor, or the recommended optimal setting, in case there is no flap sensor.
If the lever position deviates from the optimal flap position, the green speed band moves beyond the middle section. There is also an optional accustic sound overlay that indicates the moment of a flap setting change.
The associated optimal speeds come with to the polar selected and might need adjustment to represent your specific glider plane type. The display must be activated in the setup under “Screens & Gauges”, the flap sensor under “Hardware & Sensors”.

Battery Indicator

The battery indicator, once enabled, shows on the right lower corner the charge status of the battery in the form of a symbol in different colors. The exact value in percent is also displayed. When the battery is running low, the color changes from gray to yellow, then red. In addition, the red all empty battery indication does flash.
The corresponding voltages are preset for a lead-acid battery and can be modified in the setup.

All FLARM devices—Classic FLARM, PowerFLARM, and PowerFLARM RedBox with RJ45 connector—can be connected to the XCVario using standard cables. The cable shipped with the device includes a power supply option, allowing e.g. a classic FLARM device to be powered directly through this cable. This eliminates the need for additional wiring from the aircraft electrical system. FLARM devices with RJ12 or Sub-D connectors can also be connected using a RJ45 coupler or our S2 extender and plugging a RJ12 cable at the other end.

Once the FLARM is connected, NMEA data from the GPS and the barometric sensor (if available in the FLARM) are transmitted to XCSoar by default via the FLARM cable. Also tasks can be transferred to IGC-FLARM devices and FLARM settings can be configured directly. For details, please refer to the XCSoar documentation.

Recorded flights can also be downloaded from the FLARM. To do this, the FLARM must be configured in XCSoar as a separate device using the “FLARM” driver.
Once activated, the flight download can be initiated in the FLARM device menu. First, a list of recorded flights is transferred; the desired flight can then be selected for download.
Downloading via the serial interface may take several minutes depending on flight duration, as the default baud rate of 19,200 limits the transfer speed to approximately 2 kB/s. Higher baud rates can be configured for faster downloads—see the chapter on RS232 serial baud rate configuration.
If XCSoar is connected via WiFi instead of Bluetooth, the FLARM can also be configured as a separate device using the “FLARM” driver. In this case, no switching of device drivers on XCSoar side is required. Flight downloads via WiFi are possible when a WiFi-capable device is connected through the FLARM port.

Pur software version includes a sophisticated FLARM collision warning display, which graphically shows approaching traffic considering even bank angle of your glider. Depending on the alarm level, an acoustic warning signal is issued to draw attention to potential collision hazards.

In the Pur version, all routing is handled automatically by the system. Required data streams are detected and routed without user intervention, and no manual enabling or configuration of individual ports is necessary. This significantly simplifies setup and prevents incorrect or inefficient routing configurations.
Unused interfaces and data paths are automatically managed by the system and do not occupy unnecessary resources such as CPU or RAM. As a result, full performance is always available for core vario operation, regardless of the connected devices.
Incoming data from external sources—such as FLARM, GPS, or control commands—is always processed by the XCVario independently of any routing configuration. Likewise, XCVario-generated data is automatically routed to all required interfaces, including the CAN bus when the device is operating as master device.
All routing in the Pur version is inherently bidirectional, meaning data is exchanged in both directions automatically. Each interface is internally managed so that only valid and necessary connections are established. There is no need to configure manually data mappings, as this is fully controlled by the system logic. This automatic routing concept not only simplifies configuration but also minimizes the risk of misconfiguration and ensures optimal system performance under all operating conditions.

XCVario, wireless Navi and FLARM

The most common application in a single-seater glider corresponds to the default delivery configuration. In this setup, a wireless navigation device and a FLARM with standard IGC connection can be connected via plug & play, without requiring any additional configuration.
All required data streams are handled automatically. XCVario data is routed to the wireless interface, and FLARM data received on S1 is automatically forwarded to the wireless connection as well. This ensures that the navigation system receives a GPS fix and that FLARM traffic information from nearby aircraft is available for display.
Interfaces S2 and the CAN bus are not used in this configuration and therefore remain inactive.
Since this setup represents the factory default and the Pur Edition manages all routing internally, no router configuration is present. The system is immediately ready for operation after connecting the devices. The internal principles route the data on an application level from sensors towards the “Navi” device.
For general information on the system setup and interface descriptions, please refer to the Setup chapter.

XCVario, wired Navi and FLARM

When using a wired navigation device such as XCTouchNav, Kobo, OpenVario, IPX, or similar, a Navi has to be configured at S2 to enable data exchange via S2 and connected from there via a RJ45 cable as shown to the dedicated port for XCVario on that Navi.
FLARM data received on a FLARM configured to interface S1 is automatically forwarded to the wired navigation device connected to S2, ensuring full availability of GPS position, traffic information, and all required NMEA data.

The wireless interface can remain enabled on the XCVario in parallel. This allows a second navigation device to be connected wirelessly if needed—for example, in the event of a power supply issue with the permanently installed navigation device or as a fallback in case of device failure.
Additionally, the IGC file can be downloaded wirelessly to a mobile phone after the flight and declared to OLC or weglide directly from there. SD cards or USB sticks also for classic FLARMS are history using wireless technique. The navigation device connected to S2 can remain permanently installed in the cockpit. This eliminates the need for removable storage media such as memory cards or USB sticks for data transfer.

Two XCVario, two wireless Navis and FLARM

For two-seater aircraft with two wireless navigation systems, the following configuration is available and supported as a standard setup.
The front XCVario unit is connected to the FLARM via interface S1. The rear-seat display is connected to the front unit via the CAN bus, which is used to transmit all relevant XCVario data to the second display. In this configuration, only the front unit requires a connection to the FLARM.

This setup represents the simplest configuration for two-seaters. It requires only a 1:1 patch cable between the S2 interfaces of the front and rear XCVario units.

Two XCVario, two wired Navis and Power FLARM

For two-seater aircraft with two wired navigation systems, we recommend the wired configuration as shown above that is most robust against radio interference and consumes less power as no WIFI or Bluetooth connection is required.
Here both XCVarios are also connected via CAN bus. The front navigation system is connected to the front XCVario unit and the rear navigation system to the rear unit. Two of our S2 interface extenders are required to have access to the serial RS232 port on S2.

The following chapters are dedicated to the setup elements as they appear on the device in the English language. For this reason, these elements are translated only in the table of contents and not in the headings or selection lists in the chapters that describe the setup.

MC

0.5 m/s

Here, the MacCready value (MC) can be set from 0.0 to 9.9 m/s in increments of 0.1 m/s. After confirming with a short press, the variometer immediately returns to normal operation.
The MC value can be understood as an optimum airspeed selector, based on the theory developed by Paul MacCready. This cross-country airspeed selector value indicates the optimum speed at which a sailplane should be flown between thermals, depending on the expected average climb rate.

In the illustration on the right, case A shows the optimum MC setting, B a setting that is too low, and C a setting that is too high.

Bugs

0 %

Degradation of the flight polar due to insects can be adjusted using the Bugs (insects) parameter. This parameter degrades the performance of the polar parabola according to the selected percentage.
The flight polar is degraded in percentage terms, whereby the . This results in a degrading performance at higher airspeeds.

The method used is identical to the polar degradation procedure implemented in XCSoar and represents the standard approach for accounting for insect contamination in glider performance calculations.
The maximum allowed degradation is 50%, in accordance with XCSoar. For modern airfoil profiles, realistic values typically range between 10–20%. Older profiles that are more sensitive to rain and insect contamination—such as those of the LS3, Kestrel, or Nimbus 2—may approach the upper end of the adjustment range under conditions of severe soiling.

Ballast

80 liters
39.00 kg/m2

The water ballast can be set in the ballast dialog. In addition, the resulting wing loading caused by the added ballast is displayed. As a rule, 1 liter of water corresponds to 1 kg of ballast.
Example:
A glider with a wing area of 10 m² has an empty (setup) weight of 260 kg and a pilot weight of 80 kg. With 100 liters of water ballast (100 kg) in the tanks, the total take-off weight is 440 kg.
This results in a wing loading of:
440 kg / 10 m² = 44 kg/m².

Crew Weight

80 kg

Using “Crew Weight” (pilot and passenger weight), the weight of the pilot—and, in the case of two-seaters, also the passenger—should be entered, including parachutes and luggage or other items loaded to glider that are part of the weight balance, in addition to the empty weight and water ballast. The default value is 80 kg.
Entering the correct crew weight is essential for an accurate calculation of wing loading. This, in turn, leads to better agreement between the calculated flight polars and actual performance, and provides more accurate values for speed to fly, net variometer, and all other weight-dependent calculations.

QNH

1013.25 hPa

Dialog for setting the QNH value.
On the ground, set the value so that the altimeter indicates the airfield elevation, or enter the QNH provided by the nearest ATC unit.

Airfield Elevation

-1 m

If the airfield elevation is entered here, the QNH is automatically adjusted to match that elevation after power-on. In the QNH dialog, the value then only needs to be confirmed.
When landing at another airfield with a different elevation, either enter the local QNH at power-on, or update the airfield elevation to the new value if you wish to use the automatic QNH setup.
The default setting is –1 m, which disables this function. In this case, the last stored QNH is used and must be adjusted manually in the conventional manner.

Under Options there are optional software settings like Student Mode, Vario or Speed to Fly settings, settings for Audio tuning, Airspeed and Altimeter settings, FLARM alarm control, Compass and Wind settings and everything related to Screens and Gauges.

Student Mode

[Disable]
[Enable]

When Student Mode is enabled, only the settings required for flight are displayed in the setup menu. These include MacCready, Audio Volume, QNH, Ballast, Bugs, and Airfield Elevation. All other configuration options are hidden.

Student Mode can be deactivated by entering the Password “271” using the rotary control and then restarting the device. After restart, all setup options are available again.

This mode is particularly useful for club aircraft and training operations, as it helps prevent unintentional changes to critical parameters.
By default the Student Mode is disabled.

This dialog allows adjustment of the all variometer settings and parameters.

Range

5 m/s

The variometer scale is set using the range. Minimum and maximum values between 3 m/s and 7 m/s can be selected. The default range is 5 m/s.

Log-Scale

[DISABLE]
[ENABLE]

Mode

[Gross]    (or Brutto)
[Netto]
[Cruise Netto]

This option allows the variometer pointer display to use a logarithmic scale. The area around zero is expanded, while the extremes of the scale are compressed.
The main advantage is that a much larger measurement range can be displayed without losing resolution around zero. Another key benefit is that relative changes in climb rate are easier to evaluate: for example, a 20% improvement at 1 m/s (an increase of 0.2 m/s) moves the pointer the same relative distance on the scale as a 20% improvement at 5 m/s (an increase of 1 m/s).

This setting allows you to select whether the variometer functions as a brutto or gross vario, including the gliders sink rate, or as a netto vario, which compensates for the polar sink.
The “Cruise-Netto” option activates the netto automatically when the variometer is in cruise mode. Otherwise, in circling mode the variometer operates as a gross vario, indicating exactly what altitude is gained per second, which is particularly useful when circling, since the MacCready setting is based on the gross climb rate.
The audio signal follows the selected mode. In gross mode, the acoustics only indicate climb when the aircraft is actually ascending relative to the ground, means air mass climb is exceeding the polar sink rate while circling. In netto mode, the audio responds to the net climb: even small lift in the surrounding air is indicated.
This is particularly helpful when flying fast between thermals, as relevant changes in the air mass can be detected more useful, independent of polar sink, because in netto mode the sink rate of cruise flight is compensated, and polar sink make’s a big difference at high airspeeds on low wingloads.

Netto Mode

[Normal]
[Super-Netto]

This setting allows further refinement of the netto mode.
In the [Normal] setting, only the polar sink at the current speed is considered, so the variometer display corresponds exactly to the vertical movement of the surrounding air mass. The display indicates this mode with “net” in the top status line.
For example, when circling with a net reading of 2 m/s, the actual gross climb is slightly lower due to the aircraft’s inherent sink when turning. For instance, an LS-4 with a 0.6 m/s inherent sink in a turn would have a gross climb of only 1.4 m/s.
To account for this, the [Super-Netto] setting also factors the inherent sink when circling, specifically the sink that occurs at a 45° bank angle flown at the optimal speed. This way, the variometer shows while cruising even fast exactly the gross climb you would achieve while circling at that point.
In the previous example, the display would show 1.4 m/s. This reduces pilot workload, as there is no need to manually calculate the expected climb; the Super-Netto mode directly indicates whether circling is worthwhile. This mode is indicated with “s-netto” on top of it’s value.

Vario Damping

Vario Damping

Damping

4 sec

Damping sets the time constant used to smooth the variometer needle display. Because thermals are naturally turbulent, an undamped display is often too noisy to be useful. Typical time constants are a few seconds such as 3 seconds to 6 seconds.
Excessive damping with simple low-pass filters causes noticeable delay. The further optimized Kalman filter of the Pur version used here accounts for physical conditions and predictive behavior, allowing fast response without a nervous display.
Default: 4 seconds
Range: Up to 10 seconds for an even smoother indication might be selected

Averager

25 sec

Damping controls the time constant used to smooth the digital average variometer reading, displayed at the top center of the screen. The default setting is 25 seconds, meaning the display shows the average climb rate over the last 25 seconds what is a typical duration for one circle in a normal glider.
This value is common in many variometer systems and provides the pilot with a useful indication of current thermal strength.
Damping can be modified from 7 to up to 50 seconds if a smoother, a larger value is useful if a more stable average is desired.
Too little damping results in a nervous, hard-to-read display that conveys little useful information.

Climb Statistics

The Mean Climb settings determine how the glider’s average climb rate is calculated for MacCready purposes, filtering out low climbs, averaging over recent thermals (default 45 minutes), and updating at defined intervals (default 60 s) to provide a stable and responsive indicator of thermal strength. Thresholds like Minimum Climb and Major Change control which climbs are counted and when the MacCready dot visibly reacts.

Minimum climb

0.5 m/s

This setting defines the minimum climb rate that is considered when calculating the average climb. Small climb values, such as those encountered during high-speed straight flight, can be excluded. Modern recommendations (see About Gliding) suggest using only the core climb while circling for the MacCready value, and ignoring climb values during straight flight or centering. The default value is 0.5 m/s.

Duration

45 min

According to current recommendations, the climb rates from the last three thermals should be considered when calculating the average climb for the MacCready value. Analysis of many flights shows that a new updraft area is typically encountered about every 15 minutes. To account for this, the default setting for “Mean Climb Duration” is 45 minutes, meaning that only climb values from the last 45 minutes are included in the calculation. This value can be adjusted in one-minute increments.

Cycle

60 sec

This setting determines how often the mean climb is calculated. The “Mean Climb Cycle” defines the calculation interval. The default is 60 seconds, and it can be adjusted between 60 and 300 seconds. For reference, a circle with a 45° bank angle typically lasts about 20 seconds in a glider, so 60 seconds corresponds to roughly three circles. This interval is sufficient to gather enough data for the Mean Climb indicator and to clearly display the trend (via the color of the dot). Shorter intervals produce smaller values and tend to weaken the trend indication.

Major Change

0.50 m/s

This setting defines the threshold for a change in mean climb value. When the climb delta exceeds this value, the shape of the route symbol changes, and the diamond lengthens upward or downward. The default value is 0.5 m/s.

TE Compensation

With the electronic TE compensation feature, it is optionally possible to achieve total energy (TE) compensation for the variometer without a TE – probe. The principle of operation is essentially the same as conventional total energy compensation.
For the TE probe compensation choose the Probe method. For the probe-less electronic compensation choose the eComp method and set an appropriate eAdjustment factor.
A detailed discussion of the parameters affecting TE probe compensation can be found in the paper compiled by Mr. Brözel from ILEC: Total Energy Compensation In Practice (pdf)

Method

[Probe]
[eComp]

The default setting, [Probe], means the external compensation through the TE-probe is applied. This is at the moment the default approach for most gliders equipped with a TE probe.
Selecting [eComp] enables electronic compensation. Useing the eComp does not require to connect the pneumatic TE port of the variometer. A good practice would be to connect the TE port at least with the static pressure.. Only the ST port (static pressure) is used. This method calculates potential energy from true airspeed and combines it with the potential energy from barometric altimeter to generate the proper TE compensated variometer indication.
The eComp is mathematically more precise and overcomes dynamic effects by use of the AHRS sensor to improve the usability of the variometer beyond the capability of a TE-probe.

eAdjustment

100.0 %

The electronic Total Energy Compensation (eTEK) can be fine-tuned using the eAdjustment parameter. The compensation factor is adjustable from 80.0% to 100.0%.
This factor scales the theoretical kinetic energy that is converted into potential energy during changes in airspeed:

TEK = dh/dt + (eAdj/100)(TAS² / 2g).

where:

• dh/dt = measured vertical speed
• TAS = true airspeed
• g = gravitational acceleration

Adjustment Procedure

Perform several smooth push-over and pull-up maneuvers in calm air, for example between 100 km/h and 150 km/h, while observing the variometer indication.

• If the variometer indicates a climb (e.g. +1 m/s) during a pull-up when no air mass movement is present, the compensation is too low (under-compensation). Increase the eAdjustment value.
• If the variometer indicates sink (e.g. −1 m/s) during a pull-up in still air, the compensation is too high (over-compensation). Decrease the eAdjustment value.

Repeat the procedure until pull-ups and push-overs produce little or no indication on the variometer in calm air.

Damping

If the compensation cannot be optimized satisfactorily, increase the variometer damping from the default 4 seconds to 5 or 6 seconds. This reduces transient indications caused by horizontal gusts, turbulence, or rapid airspeed changes.
Even with increased damping, the optimized Kalman Filter remains sufficiently responsive to genuine changes in climb or sink rate.

Damping

5.00 sec

The Speed-to-Fly (S2F) can be damped to smooth the display, with the default set to 5 seconds. Increasing the damping further smooths the display but also delays its response. For example, after leaving a thermal, the indicated speed-to-fly does not immediately increase in response to sink.
The damping value can be adjusted up to a maximum of 10 seconds.
In modern gliders with high wing loading and high cruise speeds (over 150 km/h), reacting to short-lived thermals is often counterproductive. Rapid changes can lead to high g-load due to inertia, reducing overall performance. Some damping is therefore beneficial. It allows the pilot to respond smoothly to sustained climbs or prolonged sink (“blue holes”), rather than reacting to every small fluctuation.
The default value of 5 seconds can be adjusted by the user to suit personal preference and aircraft characteristics.

Blockspeed

[DISABLE]
[ENABLE]

By enabling Block Speed [Enable], the vertical motion of the surrounding air mass (as indicated by the net variometer) is ignored. Only the aircraft load and the MacCready value are used to calculate the optimal speed.
In this mode, the speed displayed by the speed-to-fly command remains constant while circling in a thermal, reflecting the principle that reacting to very short-lived thermals (a few seconds) is generally ineffective due to aircraft inertia.
This was confirmed by numerical simulations at the Technical University of Munich, which showed that the MacCready speed for the upwind case only becomes relevant for thermal durations of approximately 20–30 seconds (about half the period of the phygoid or natural “pump” frequency), or when deliberately pushing the aircraft aggressively.
Some experienced pilots adopt this style and achieve very good average speeds.

S2F Mode

[Manual]
[AutoSpeed]
[AutoFlap]
[AutoTurn]
[Vario fix]
[Cruise fix]

The S2F “Mode” determines how the instrument switches between circling and speed-to-fly. Several options are available:
[Manual] will control the S2F by the a switch or push button connected to the S2F labeled wires at XCVario cable tree. At any time you may also use a remote stick sending SW commands to XCVario to manually toggle between vario and speed-to-fly, what provides maximum flexibility.
[AutoSpeed] (default): The instrument automatically switches from circling to speed-to-fly at a preset airspeed. The switch-over speed is configured in the “AutoSpeed Thresh.” menu.
[AutoFlap] setting changes the mode depending on your flap position if there is a flap sensor available.
[AutoTurn]: The instrument automatically switches to circling mode when the measured rotation rate exceeds the AutoTurn Rate (in degrees per second). The rotation rate is averaged over 20 seconds and includes a 20% hysteresis—the mode only switches back when the rotation rate drops 20% below the set threshold.
[Vario fix] or [Cruise fix]: The instrument remains in the selected mode and does not switch. In practice, when flying cross-country, these settings are rarely useful. Fixed vario mode may make sense if you prefer a conventional variometer display and do not want to fly according to speed-to-fly.

S2F Switch

[Disable]
[Switch]
[Switch Invert]
[Push Button]

The hardware type of speed command switch can be configured. The default is [Switch], that may be configured as inverted as well, but a [Push Button] can also be selected, which toggles the mode each time the button is pressed. This is particularly useful, for example, when using a remote stick input device with integrated buttons.
The [Switch Inverted] option reverses the switch logic: the speed command mode is selected when the switch is open rather than when it is closed, useful e.g. if an existing switch is wired or working like that.
Note: The switch can change modes at any time, even if [AutoSpeed] or [AutoTurn] is active, unless the switch type is set to [Disable].

AutoSpeed

120 km/h

This is the airspeed in AutoSpeed mode at which the variometer switches from circling to speed-to-fly / cruise mode. The default is 120 km/h.
For gliders with higher wing loading or modern high-performance designs, this value can be adjusted higher as appropriate.

AutoFlap Pos.

1.00 flp

This setting defines the flap position at which the S2F mode should be switched in the “S2F mode”. By default, the flap position is set to +1.00 flp.
Note: This is only visible if your glider has a flap sensor equipped and enabled in the XCVario.

AutoTurn Rate:

10 °/s

This sets the turn rate threshold (in degrees per second) at which the device switches to S2F mode in AutoTurn mode.
Lower values cause the device to switch to circling mode earlier, while higher values delay the switch due to averaging over approximately 20 seconds.
For reference, a typical 25-second circle corresponds to a rotation rate of 360° / 25s = 14.4°/s. The default threshold is 4°/s.

Switch Lag:

5 sec

The Switch Lag setting smooths the automatic activation and deactivation of speed-to-fly mode in AutoSpeed mode. Without it, the system may toggle rapidly when airspeed hovers near the AutoSpeed threshold. The default hysteresis is 5 sec: the instrument switches to speed-to-fly mode 5 seconds delayed. It can be adjusted from 2-20 seconds.

Note: Any automatic variometer mode switching can be overruled by a connected switch.

The acoustic signal generator is an integral functional subsystem of the electronic variometer and is directly coupled to the real-time vertical speed and speed-command processing chain. Its primary purpose is to offload visual attention by providing continuous auditory feedback, enabling uninterrupted external lookout and traffic awareness. In the Pur version, the audio engine supports multi-spectrum tone generation with independent control of fundamental frequency, harmonic content, modulation envelope, and inter-tone timing. Climb, sink, and speed-command states are encoded through defined variations in pitch, repetition rate, duty cycle, and secondary tone components, allowing unambiguous state discrimination across the full operating range. Audio output is either from integrated speaker or to an external speaker, ensuring adequate sound levels and intelligibility under varying cockpit noise conditions.

V-Tone at Sink

[Enable]
[Disable]

Decide if variometer audio shall be mute or not when indicating a descent.

Default Volume

25%

In this setting, the volume that is used after switching on the device is configured. The default is 25% volume.

Alarm Volume Raise

40%

In this setting, the volume that is used for alarms e.g. FLARM traffic alarms, stall warning, etc. is configured. The default is 40% and can be raised to any value.

Stall Warning

[Disable]
[Enable]

Options to enable acoustic stall warning.

Split Volume

[Disable]
[Enable]

Options to maintain an individual volume level in Cruise or in Vario mode. By default this feature is enabled.
With this feature, which adjusts the volume separately in Vario mode and in speed-to-fly mode, the volume can be adjusted to the different acoustics in the cockpit when circling and in fast flight. In older gliders flying at high speed, a higher volume is often necessary so that the sound can still be heard. The feature takes some getting used to and is switched off by default. With [Enable] it is activated.

Cruise Audio

[Speed2Fly] 
[Vario]

This setting is used to select which sound signal is generated in speed command mode. In the [Speed2Fly] mode, a tone is generated which signals the deviation from the recommended speed. If the airspeed is too high, a progressively higher, optionally interrupted tone is generated, if the airspeed is too low, a lower tone. In the [Vario] setting, the audio signal remains in the vario setting and can, for example, signal net climbing if the vario is set to “Netto” or “Cruise Netto”. For more information, see the “Vario Mode” setup.

Tone Style

Preset scheme

[XCVario] 
[eXtended]
[Ilec]
[Westerboer]
[Zander]
[Borgelt}
[Custom]

The variometer provides a selectable set of predefined tone styles, each representing a distinct acoustic parameter set. These tone styles differ in fundamental frequency mapping, modulation depth (tone variation), pulse (chopping) characteristics, duty cycle, harmonic structure, and transition behavior between climb, sink, and neutral states. The purpose of these profiles is to replicate the characteristic sound signatures of variometers produced by various manufacturers over past decades, allowing pilots to retain familiar auditory cues and apply known response patterns.
Available tone styles include XCVario, eXtended, Ilec, Westerboer, Zander, Borgelt, and Custom. While the underlying signal processing remains identical, each style applies a vendor-specific psychoacoustic tuning of frequency scaling, tone spacing, and temporal behavior. The Custom profile allows user-defined parameterization for precise adaptation to individual preferences or legacy device emulation.

CenterFreq

500 Hz

The variometer center frequence at no climb or no S2F deviation, and can be modified in 10 Hz steps between 200 Hz and 2000 Hz. The default is 500 Hz.

Tone Variation

2.00 fold

This parameter defines the total frequency span of the acoustic output in terms of octave range relative to the defined Center Frequency. It specifies how many octaves the tone modulation extends upward to the maximum frequency and downward to the minimum frequency. The parameter is adjustable in increments of 0.1 over a range corresponding to frequency ratios from 1.5× to 4.1×. The default setting using XCVario scheme is 2.0 fold, which, for a center frequency of 500 Hz, results in an upper frequency limit of 1000 Hz and a lower limit of 250 Hz. Excessively large values may shift parts of the acoustic signal outside the optimal response range of the loudspeaker and the most sensitive region of human hearing, potentially reducing audibility and tonal clarity.

Dual Tone

[Disable]
[Enable]

This configuration refines the variometer tone generation in case the setting “Chopping” is enabled.
This parameter selects the tonal generation mode of the variometer’s acoustic output. Deactivated, a single tone pitch is emitted with periodic interruptions, resulting in a pulsed sound pattern (e.g. di di di di). Once activated, the acoustic output alternates between two tone pitches in a sequence (e.g. di da di da). The default configuration is off, together with “Chopping” on.

Chopping

[Disabled]
[Vario Only]
[S2F Only]
[Vario and S2F]

When acoustic output is enabled in Vario or Speed-to-Fly (S2F) mode, positive values can be rendered with periodic short interruptions (“chopping”) of ca. 100 ms duration. The repetition rate of these interruptions increases with the indicated vario or S2F deviation, providing an additional temporal cue proportional to the magnitude of the displayed value.
The chopping function can be configured as Disabled, applied to Vario only, to S2F only, or to Vario and S2F, with the latter being the default setting. At full-scale indication, the interruption repetition rate reaches exactly 10 Hz, while the minimum repetition rate is 1 Hz. Between these limits, the interruption frequency scales linearly with the corresponding display value.

Harmonics

[None]    – pure fundamental tone (classic XCVario sound)
[Some]    – light overtones for better clarity
[More]    – extended spectrum with stronger harmonics
[Sparky]  – highly articulated, bright sound for maximum clarity

The Harmonics feature enhances the classic vario tone by adding controlled overtones to the base frequency. Instead of a single pure tone, the sound spectrum becomes richer and easier to interpret in noisy cockpit environments. By varying not only pitch and cadence but also timbre, small indicator changes become audible faster, supporting precise flying with minimal visual attention.

Audio Response

1.00

This parameter controls how the frequency of the audio generator responds to the climb rate. 1.00 means a linear connection. A value > 1.00 corresponds to an exponential behavior while < 1.00 is logarithmic.

Range & Deadbands

Range

[Fixed 5 m/s] 
[Fixed 10 m/s]
[Variable (=N m/s)] 

This setting controls whether the tone generator uses a fixed range ([Fix 5 m/s], [Fix 10 m/s]) or follows the current variometer range ([Variable = N m/s]). The range determines the frequencies and intervals the generator produces at minimum and maximum values, useful for weak climbs, where, for example, at 2 m/s with a scale set to 2 m/s in the variometer will sound like 5 m/s in fixed mode. Default: Fixed 5 m/s.

Deadbands

Lower/Upper Vario: [–0.3 .. +0.3 m/s]
Lower/Upper S2F: [–10km/h .. +10 km/h]

The vario deadband defines a vertical-speed interval around zero in which the acoustic output of the variometer is suppressed. Within this range, no climb or sink tones are generated. The deadband limits are configured via independent Lower (negative vertical speed) and Upper (positive vertical speed) threshold parameters. By default, the deadband is set to ±0.3 m/s. This function attenuates low-amplitude vertical-speed fluctuations caused by turbulence or sensor noise and ensures silence during ground operations, without requiring a reduction of the volumel.
The Speed-to-Fly (S2F) function also implements a configurable deadband. By default, the deadband is set to ±10 km/h around the target speed. As long as the actual airspeed remains within this tolerance band, the S2F acoustic output is muted. The audio indication is enabled only when the deviation from the target speed exceeds the defined deadband, preventing unnecessary audio activity for minor speed variations and reducing pilot workload.

This interface allows configuration of all barometric altimeter parameters.

Altitude Mode

[QNH]
[QFE]

The altimeter can be set either to QNH or QFE mode.

QNH is the altimeter setting that makes the altimeter read airfield elevation above mean sea level (MSL) when the aircraft is on the ground. In flight, it shows altitude (AMSL).
QFE is the setting that makes the altimeter read zero on the ground. In flight, it shows height above the airfield.
If the standard pressure of 1013.25 hPa is set (QNE), the altimeter is useful to keep flight levels (FL).

Auto Transition

[Disable]
[Enable]

With this setting, the altimeter can be automatically switched to the QNH standard pressure of 1013.25 hPa once the aircraft passes the defined transition altitude or also called transition layer.

Transition Altitude

50.00 FL

With this setting, the country-specific transition altitude can be defined as a flight level (FL). This parameter is only relevant when the automatic transition function is activated. Below the transition altitude, the altimeter operates using the local QNH setting; above it, the system automatically switches to QNE based on the standard pressure setting of 1013.25 hPa.

Alt. Source

[TE Sensor]
[Baro Sensor]
[GPS/FLARM]

Either the TE sensor or the baro sensor or even an external source like GPS or FLARM can be selected as the altitude source. The baro sensor is the default. Using the TE sensor is only meaningful if total energy altitude is required or for specific test scenarios.

Alt. Quantization

[Disable]
2
5
10
20

This setting defines the quantization interval of the altitude display between 2 and 20 meters (or 6–60 ft). In the image above, the default interval is 10 meters. The last two digits of the altitude then scroll upward or downward like a mechanical counter wheel, which greatly improves readability during altitude changes compared to a standard digital readout.

Level Threshold

[Disable]
[Level 1]
[Level 2]
[Level 3]

When a FLARM device is connected, the variometer display becomes secondary in priority during imminent collision situations. The connected device can then serve as both an acoustic and optical FLARM warning system, similar to common FLARM secondary displays, but providing more detailed information.
FLARM warnings are divided into three levels, corresponding to the time remaining before a potential collision:

• Level 1: Warns already of a potential collision 13–18 seconds before impact. This is the default setting and is triggered at the lowest alert level from the FLARM.
• Level 2: Warns 9–12 seconds before potential collision, indicating an increasing threat.
• Level 3: Warns 0–8 seconds before potential collision, representing immediate danger.

Note: Refer to your specific FLARM device documentation for detailed behavior of alarm levels.

Timeout

5 sec

FLARM Alarm Display Duration
This setting controls how long the FLARM alarm warning remains visible on the screen after the alarm has been triggered.

• Default Duration: 5 seconds.
  • Combined with the active alarm time, this is usually sufficient to read and interpret the display safely.
• Adjustable Duration:
  • Longer display time: Useful for feature testing, training, or detailed analysis of traffic situations.
  • Shorter display time: May be advantageous in competition settings, for example, when circling in a thermal with multiple gliders, to reduce screen clutter and maintain focus.

This setting allows pilots to balance information visibility with operational efficiency, depending on the flying situation.

Check

1. [Cancel]
2. [Cross Deeper]
3. [Cross Higher]
4. [Head-on Deep]
5. [Overtake Left]
6. [Cross Level]
7. [Circling Left]

The FLARM alarm simulation allows pilots to trigger and view different types of FLARM warnings to understand how they appear on the display and practice interpreting them. Each simulation option represents a specific traffic pattern and it’s traffic display.
Simulation Options:

1. Cancel the current FLARM simulation, nothing happens.
2. Another aircraft is crossing your flight path at a lower altitude than your own from the left. The potential conflict is “below” you.
3. Another aircraft is crossing your path at a higher altitude from the right. The traffic is “above” your current level.
4. head-on approach with another aircraft that is below your altitude. This is a more urgent alert as the risk of collision is significant if paths are not adjusted.
5. Another aircraft is overtaking, coming from behind on your left side. You should monitor and maintain safe separation.
6. Another aircraft is crossing your flight path at approximately the same altitude. This is typically considered a medium-priority alert, requiring awareness and possible avoidance.
7. You are approaching a in a left circle climbing glider. Relative speed changes all of a sudden when the other aircraft turns towards you.

Source

[XCVario]
[External]

For wind calculation using “XCVario” source, the wind is calculated during circling. The procedure is straightforward, the calculation relies entirely on GPS data so a Flarm or other GPS source is necessary. During the calculation, the ground speed vectors are analyzed, and the wind vector is determined from the directions corresponding to maximum and minimum ground speeds.
The method is effective even if the circles are not perfectly circular, though maintaining a relatively constant speed while circling improves accuracy.
Measurement quality is further enhanced through intelligent filtering, which incorporates a quality factor based on the correlation between the directions of minimum and maximum ground speeds. Typically, two to three circles are sufficient for an accurate wind measurement, while an initial wind estimate is available after just one circle.

With the “External” setting the wind calculation from an external device like the anemoi. Have a look at anemoi live wind indication
The live wind indication is overlayed to the thermal assistant, when circling, else it is displayed on top of a wind rose at the same place. Indication is split into the wind strength rounded to e.g. km/h, and an arrow tip on the opposite side on the rose.

Anemoi live wind display showing 12km/h from ca. behind.

Reference

[Heading-Up]
[North-Up]

Display the wind arrow indicator either relative to your heading, means relative to the body of your plane, or relative to “North-Up”, means the wind is displayed relative to north on top of the Indicator. The default is “Heading-Up”, that means indication is plane relative.

Variometer

On Top

[Disable]
[IAS Speed]
[TAS-Speed]
[GND Speed]
[Altitude]
[Speed2Fly]
[McCready]
[Net. Vario]
[OATemp]
[Heading]

This setting controls which value will be displayed at the right upper digital gauge, per default it is disabled. The above selection allows which values can be shown for that field, such as various speeds like IAS, TAS, GS, the calculated speed to fly according to MC, the MC value itself, the netto vario, OAT temperature, a ‘pseudo’ heading calculated from GPS ground course plus wind.

Bottom

[Disable]
[Altimeter]
[Wind]

This setting controls which value will be displayed at the right lower gauge, per default the altimeter is displayed there.
This menu allows configuration of screens displayed and individual elements shown there at defined places.

Speed2Fly

[Disable]
[Enable]

Hide or show the command arrows for speed to fly.

Therm.-Assist

[Disable]
[On-Top]
[Heading-Up]

Enable here the thermal assistant to indicate the climb rate within a your circle. It displays colored dots around the center of the display according to the momentary climb rate. Brighter and bigger dots indicate a faster climb rate than darker smaller dots. The reference to the gliders heading can be selected to “On-Top” or to “Heading-Up”.

Flap-Assist

[Disable]
[Enable]
[En.Audio]

This setting controls whether the flap indication is shown.

The flap assistant indicates the current or optimal flap setting and a green speed band for this flap setting respecting the current wing load.
Depending on a flap sensor being installed, the flap assistant provides different information:

• If a flap sensor is installed, the current flap position label is shown in the middle. As long as the actual flown speed fits to the flap setting the speed band overlaps with the middle section.
• In case no sensor is available, the optimum flap setting is displayed instead.
• In any case, when the audio is enabled the flap position change is also indicated through a recognizable sound overlay.

Battery

[Disable]
[Percentage]
[Voltage]

The battery status display. Options include disable or showing the battery status as a percentage, or as a numeric voltage value without battery symbol.

G-Meter

The G-Load Display is an option to show the current load factor acting on the glider. Peak values are stored in flash memory and can be viewed on this display or as well in the setup menu. In addition, the maximum indicated airspeed is displayed. Peak values that exceed the configured limits are shown in red. The sensor sensitivity is setup to measure up to 8 g either positive or negative.

Screen Mode

[Disable]
[Enable]
[Primary]

The G-Meter display can be enabled on demand, or set as a primary screen of the variometer, e.g. for aerobatic flights.

Limits

Red/Yellow positive Limit: [  5.0 / 3.0 ]
Red/Yellow negative Limit: [ -3.0 / -2.0 ]

Extreme Recordings

All peak recordings experienced by the aircraft since the last reset are listed here.

Reset Peak-Hold

[Cancel]
[Reset]

This resets the recorded peak values to zero, clearing all stored peak measurements.

Horizon

[Enable]
[Disable]

The XCVario, equipped with an Inertial Measuring Unit (IMU) and an Attitude and Heading Reference Systems (AHRS), offers a simple horizon display for situational awareness, similar to the horizon in XCSoar. The display is square and features a pitch scale and the indication of the bank angle on top. Small lines on the scale represent a 5° pitch angle, larger lines indicate 10°.
Once Enabled it can be activated by a button press.

To correct for the specific ground angle of attac and level the horizon display when flying the display has a quick in-page setup feature. A long-press of the rotary button enters the “Pitch Adjust” setup and let you level the pitch of the horizon.

Pitch Adjust: -20°

Important: The horizon is not intended as a blind flight instrument. Instead, it serves as a tool for training and monitoring, such as maintaining the bank angle of e.g. 45° while thermaling. It provides sufficient accuracy for these purposes under normal flight conditions.

The System menu is the central access point for all core configuration, and maintenance functions of the XCVario device. It provides access to software updates, hardware and sensor configuration, power and battery settings, unit selection, AHRS calibration, display behavior, and communication interfaces. These settings define how the device operates internally, how it interacts with connected sensors and peripherals, and how it integrates into the overall avionics environment.

Each functional area available through the System menu is described in detail in its own dedicated chapter later in this documentation. This structure allows users to focus on individual subsystems while maintaining a clear understanding of how the various system components are organized and interact within the XCVario platform.

This chapter provides a consolidated overview of system-level settings, optional configuration features, and maintenance functions, serving as a reference for configuring and maintaining the XCVario system.

XCV Device role

[Master]
[Second]

Set the role of your XCVario here.
Note: As this being the most central setup a reboot is required imidiately after changing the role of the variometer.
In a single-seater aircraft, this is normally [Master] and should not be changed.
In a two-seater aircraft, the second device—typically installed in the rear seat—must be set to [Second].

ystem Essentials

Software

XCVario S/N: 1234

The unique variometer ID, used for Bluetooth ID and WiFi Id of this Device e.g.: “XCVario-1234”

Rev: 2.0.4-0-ga2494fcd

The installed software version. It is a plain github version string format. In this example major-, minor-, fix- revision and additionally the hash from the source control system.

Internet Access

Access Point

[Cancel]
[Select AP]

Select the AP for software update. This is not yet fully supported and will come asap.
[Check for the Update]

Update

[Cancel]
[Start Webserver]

Check for the Update

The feature is under development, and required an access point to be configured in the previous step. As soon as it is operational, it will be described here.

Start Webserver

This is the classic software update method provided by XCVario. The device software is available as open source on the project’s GitHub page. For downloading the firmware file and performing the update, Mozilla Firefox is recommended. Other browsers may also work; however, some browsers or operating systems may incorrectly handle the binary file extension, which can lead to download or installation issues.

Official software releases are published at: https://github.com/hjr/XCVarioPure/releases

Firmware updates can be installed via the built-in WiFi access point of the variometer. A smartphone, tablet, or laptop can be used for this purpose. Before connecting to the XCVario WiFi network:

1. Download the desired firmware file (for example, xcvario_pur-2.0.4.bin) using an internet connection.
2. Save the file locally on the device that will be used for the update.
3. Verify that the downloaded file size matches the value shown on the release page.

Once the file has been downloaded and verified, connect to the XCVario WiFi network and perform the OTA update through the web interface.
Selecting [Webserver] the device will reboot and fall into the following screen to connect with your mobile device and upload the previously downloaded file.
Connect your device to the WiFi network “XCVario OTA” provided by the variometer. It uses WPA2-PSK security; the password is displayed on the variometer, here you see “xcvario-21”.

After connecting, open a web browser and navigate to http://192.168.4.1. Ensure that the browser uses the http prefix, not https, and disable any automatic redirection if necessary. Use the browser interface to select the firmware file and upload it. The update dialog shows progress information and confirms success both in the browser and on the variometer display.

Very First Pur Start

The very first boot of the Pur Variometer is guiding through all factory calibration and test steps. In case you upgrade from a previous XCVario firmware one additional calibration step left to do and prevents you to be able to leave the factory jail.
To properly do the IMU bias calibration it is necessary to remove the variometer from the instrument panel. Prepare a smal leveled mount to position the variometer in all 6 orthogonal orientations.

IMU BIases: Acc Calib.

Choose this setup to calibrate the accelerometer biases in all six orthogonal orientations. Wait for the IMU sensor to reach the proper temperature. Then start with a button press. The following procedure does no further needs button presses, rather than the IMU sensor triggers when the variometer comes to a stand still (rest). Then it takes a couple measurement samples and plays a chimes sound to let you know to go on to the next orientation.
The measurements will be checked roughly on a proper orientation spacing, but not on proper leveling. A missalignment to horizontal leveling will result in a skewed horizon display. There is a video that illustrated the easy procedure.
Once the accelerometer biasses calibration succeded you might leaf the factory setup and the variometer falls back into normal operation.

Leak Test:

Very likely the XCVario also will complain about a missing leak test, because there is no result stored in flash memory as the Pur Edition now does. Your variometer was for sure leak tested, so just start the test and wait 60 seconds. Not putting any pressure on the tubes will not test, but passe the test, so that you can leaf the factory setup.

Check Configuration After Updating

After completing the update, review all settings. In most cases, existing settings are retained, but new firmware versions may introduce additional features with default values that require adjustment. Always consult the corresponding release notes. When updating from older releases crosscheck settings and and see if glider polar selected is still correct and also connections to external gadgets are configured as expected.

Troubleshooting

If transmission errors occur, the new software is discarded automatically and the device restarts with the previously installed firmware. The variometer uses two separate firmware areas; new software is always written to the inactive area to ensure continuous operability. If software update mode is entered but no file is selected, the system will automatically time out after 15 minutes and restart with the existing firmware. This process can also be cancelled manually at any time by pressing the rotary control.

If the WiFi connection cannot be established, verify that your device allows connections to networks without Internet access and confirm any related system prompts. The variometer selects a random WiFi channel each time the update function is started, improving reliability in environments with many occupied channels.

Show Boot Messages

All boot messages are recorded and can be shown even at a later time after booting up the device for diagnose.

Factory Reset

[Cancel]
[ResetAll]

This function allows all device settings to be reset to their factory defaults. All user-defined settings that differ from the default values will be permanently lost. After performing a reset, polars and all other aircraft-specific parameters must be reconfigured. A factory reset can also be executed during a software update via the browser by using the “Factory Reset” button.

Expert Menu:

The Expert Menu is dedicated for troubleshooting and for experts only, using this in field may cause performance issues and also malfunction in case those special parameters are not set wisely. From that reason it is not intended to be used in common and also not recommended, so the password will not be published.

With the glider type dialog, most importantly the polar for the aircraft type is selected, masses can be adjusted and the polar that is set can be tuned manually.

Type

[User Polar]
[Antares 20E]
[ASK 21]
:

This setting is used to select the flight polar corresponding to the aircraft type. In addition to the predefined entries, the first entry stands for a user defined polar that is provided for aircraft types that are not included in the library. The user polar is selected by default and is initialized with values corresponding to an LS4a. These values can be adjusted to match any custom or measured flight polar.

Any modifications made to the selected polar are automatically reset when a different aircraft type is chosen. In normal operation, only the aircraft type needs to be selected; manual adjustment of these parameters is usually unnecessary. All gliders in the database that are equipped with flaps provide recommended speed ranges per flap setting as written in flight manual, or taken from diagrams or polars. Additional aircraft types can be integrated into the library by XCVario upon request and become available automatically with the next software update.

A continuously growing polar library is provided. The current list of supported aircraft polars can be found in the GitHub repository in the file PolarTable.txt.

Reference Polar

Ref Wingload

34.4 kg/m2

Using the following setting, the reference wing loading and the sink rates for individual airspeeds can be modified. The reference wing loading represents the condition under which the flight polar was measured and is typically specified with the polar data. If the actual wing loading of the aircraft is higher, even without water ballast, this must be accounted for using the Empty Weight setting described below. In general, the reference wing loading should not be changed and should always match the values provided with the selected polar.

Speed 1, 2 ,3

Speed 1:  80 km/h Sink 1: -0.66 m/s
SPeed 2: 125 km/h Sink 2: -0.97 m/s
Speed 3: 175 km/h Sink 3: -2.24 m/s

For the selected reference wing loading, the corresponding sink rates are defined at three operating points using Sink 1, Sink 2, and Sink 3, each associated with a specific airspeed via Speed 1, Speed 2, and Speed 3.
Ideally, the first speed is chosen close to the minimum sink speed, the second represents a typical cruise speed, and the third corresponds to a higher airspeed relevant for fast cruise operation. You may modify those values at any time, but when a new polar is selected, the modification are lost and new defaults from the polar library will show up for the new glider.

Stall Speed

74 km/h

This setting defines the aircraft’s stall speed and is used by the XCVario for flight state awareness and speed-related indications. The stall speed should be configured according to the aircraft flight manual and must correspond to the clean configuration without airbrakes extended. The entered value represents the stall speed at the reference wing loading. Changes in wing loading due to ballast or payload are taken into account automatically by the system, provided the corresponding weight settings are configured correctly.
Correct configuration of the stall speed is essential for accurate speed margin indications and related flight safety functions.

Max Ballast

160.00 liters

This setting allows you to adjust the maximum permissible water ballast. The default value is typically defined by the aircraft type and sourced from the polar library according to the manufacturer’s specifications. It can be modified here to account for changes such as winglets or different water ballast tank installations.

Wing Area

10.5 m²

This setting allows you to adjust the wing area. Although this parameter is normally defined by the aircraft type, it can be modified here to account for changes such as attachable wing extensions or winglets.

Empty Weight

265 kg

The “Empty Weight” parameter allows a more accurate definition of the aircraft’s empty mass. Over time, gliders often gain weight due to added instruments, winglets, repainting, or moisture absorption in the composite structure (CFRP or GFRP). To account for this, the empty mass can be set higher than the original value used to derive the gliding polars.

By default, when a polar is selected, the empty mass is calculated as the flight mass minus the pilot’s weight. Increasing the empty mass raises the wing loading, improving performance at higher speeds, similar to the effect of adding water ballast.

Maximum Speed

270 km/h

By default, the maximum target speed is set to 270 km/h IAS (indicated airspeed). The S2F computer is using it to limit any commanded speed accordingly.

Flap Levels

NOTE: The speed ranges assigned to each flap setting are derived either from the aircraft flight polar or from the aircraft flight manual. Flap speeds are included in the XCVario polar library.

Takeoff Flap

3 .

This setting controls the assistant to show the designated takeoff position (usually first positive detent) before takeoff. This setting provides increased lift at low airspeed with acceptable drag during ground roll and initial climb. Maintain takeoff flaps until safe airspeed and height are achieved, then retract smoothly to neutral or climb configuration.

Add Level

Label: -2
Minimum Speed: 155 kmh
Create it: [ Cancel / Yes ]

Each level consists of a label and the minimum speed for it’s speed band.
Set the label for the new flap level. Flap lables can have up to three characters and can be manipulated through the line text editor. It has two modi: Move the cursor as the character is displayed in yellow; press button and change the character in red with the rotary knob. A short press toggles the mode. Long press exits the line editor. An underscore “_” represents a space in the line editor.
Set the minimum speed at which this flap setting is recommended to use. Mass conditions according to the given polar reference.
Confirm at the end of this dialog to create the flap level. It will be sorted into the list according to the speed you entered.

Change a level (4. Level +2> 74 kmh)

Enter into each level and change speed, label or remove that level by selecting “Yes” in the corresponding field and push to confirm.

Label: +2
Minimum Speed: 74 kmh
Remove level: [ Cancel | Yes ]

An example of how this list may appear.

0. Level -2> 125 kmh
1. Level -1> 105 kmh
2. Level 0> 95 kmh
3. Level +1> 80 kmh
4. Level +2> 74 kmh

For international operation in accordance with local conventions, the measurement units for variometer, airspeed, altitude, temperature, QNH, and distance can be configured individually. The available units include SI units and non-SI units accepted for use with SI, as defined by ICAO.

The factory default unit settings reflect common aviation practice in central Europe. Available unit options for each parameter are listed below; default values are shown in bold.

Altimeter

[Meter (m)]
[Feet (ft)]
[FL (FL)]

Airspeed

[Kilom./hour (km/h)]
[Miles/hour (mph)]
[Knots (kt)]

Vario

[Meter/sec (m/s)]
[100 Feet/min (hfpm)]
[Knots (kt)]

Temperature

[Celcius]
[Fahrenheit]

QNH

[Hektopascal]
[InchMercury]

Distance

[Meter (m)]
[Feet (ft)]

DISPLAY

Orientation

[NORMAL]
[TOPDOWN]

By default, the variometer display is configured upright with the rotary knob on the left side. In case it suits you better to have the rotary knob on the right side of the display, choose the [TOPDOWN] orientation. An experimental [NINETY], for a 90° degree mount with the button underneath the display is available in expert mode.

Pixel Test

[Cancel]
[Start]

The display test shows a fully white screen as well as a fully black screen in sequence, in order to detect faulty pixels.

Rotary Knob

Sensitivity

1 Indent
2 Indent

This setting allows adjustment of the rotary switch sensitivity. Some rotary switches generate two pulses per detent; in such cases, the display shows “2–4 indents per increment” to prevent skipping values. The optimal sensitivity is configured at the factory and typically does not need to be changed. The default setting of 1 indent per increment is recommended.

Enter Setup by

[Short-Press]
[Long-Press]

This setting allows you to select whether the XCVario opens the setup menu exclusively on a long button-press. By default the short press cycles through all configured screens with the setup screen as last in the list of screens. If you prefer the quick access of the setup menu using the long press from any screen select [Long-Press], leaving the short press reserved for screen navigation.

Speaker

[Enable]
[Disable]

Option to disable the audio amplifier. It does drop the power consumption a bit, e.g. for a two seater setup. Pressing the button on [Enable] starts a sound check melody.

Flap Sensor

Flap Sensor

[Disable]
[Enable]

Configure the XCVario flap sensor here after connecting the hardware to your device.

Sensor Calibration

[Cancel]
[Start]

Starting the sensor calibration will guide you through all configured flap positions of your glider.

Gear Warning

[Disable]
[S2 Flap positive]
[S2 RS232 positive]
[S2 Flap negative]
[S2 RS232 negative]
[External]

With the “Gear-Warning” a warning can be triggered in the case of extended brake flaps and retracted landing gear. The magnetic contact on the brake flap must be closed when it is retracted, and the contact on the landing gear when it is fully extended.

Note: The warning can be acknowledged by pressing the rotary and then turns off for 500 seconds or about 8 minutes.

Both contacts are switched in parallel with one end connected to ground (GND, battery minus) and the other end connected to pin 6, the flap sensor input, to S2 and connected to +12 volts via a pull-up resistor. Alternatively, pin 4 on S2, the RX pin of the RS232 interface, can be used, and there is an option for external [External] commands that can be send by an external device in order to trigger the gear warning, see the „$g“ commands section for details about this.

The warning is given optically with a textual display "Check GEAR" in the popup text field, and there is an audible warning tone, and has priority over the other displays, with the exception of the stall warning.
The feature is available if either the flap sensor or the RS232 interface on S2 is not configured, i.e. setting: Disable is mandatory there and is switched off by default, or if you don’t use the flap sensor input.

The switching of the two magnet contacts is shown on the right, both must be designed as normally open contacts, i.e. they must be shot in the vicinity of the magnet. The pull-up resistor R2 is necessary for a high-level and should be in the 100 to 150 Kilo-Ohm range and at least 1/8 watt of power.

With the “negative” options you can also use contacts, which are to be laid in series and then close when the flaps are not locked, or the landing gear is not fully locked. The last option “Extenal” means the gear warning information is received by XCVario protocol via any supported interface.

Airspeed

AS Calibration

0 %

With the AS Calibration, a proportional calibration of the airspeed can be carried out. The calibration can be set in 1% steps in the range of +-10%. For example, with a calibration of +5%, instead of 100, 105 km/h will be displayed. This is normally not necessary, as the accuracy of the sensor is usually completely sufficient, however, the pressure readings in the aircraft can run incorrect values, and so there is an option here to minimize these errors. Default is 0% calibration. The AS calibration calibrates the respective value according to the setting IAS/TAS.

Set Zero

[Cancel]
[Now]

With this option, the zero point of the airspeed sensor can be re-calibrated. The high accuracy of the airspeed sensor is ensured by a daily calibration of the zero point. This is normally carried out automatically on the ground when the power is turned on and is therefore only necessary in exceptional cases. At low speeds < 30km/h, very low pressures are relevant, different wind pressures from a gust or the propeller on the statics or the pitot tube when switching on can possibly lead to a deviation. If the display on the ground does not show exactly zero due to an incorrect zero point, this can be a remedy.

Swapped Tubes

[Straight]
[Swapped]

Some older HW types have AS sensors with tubes swapped, in case there is no airspeed reading, the option [Swapped] will correct for this. This configuration option is only visible for XCVario hardware that has those differences.

IMU & AHRS

All XCVario devices from the 2021 series onward feature a 6-axis Attitude & Heading Reference System (AHRS) or IMU sensor chip, which includes accelerometers for all three axes and gyroscopes measuring rotational speed in all three axes.
The sensor is used to record acceleration or load factor (G-load), for example during circling, which effectively acts like additional ballast by increasing optimal glide performance. It also provides data for the artificial horizon and supplies load factor information to XCSoar.

Temp Control

45 °C

The AHRS chip temperature can be regulated to a constant setpoint by an internal heating. A stable working point improves G-meter and gyro accuracy, resulting in a more accurate artificial horizon. The default setpoint is 45 °C. It may be adjusted for different climates. Setting the value to –1 °C disables this function.

A temperature rise of about 35 °C above ambient is possible, providing stable regulation at a 45 °C setpoint over ambient temperatures in cockpit of roughly from 10 °C to 45 °C.

AHRS RPYL

[Disable]
[Enable]

This function can be used to activate a data stream generated by a Levil AHRS. It produces $RPYL and $APENV1 data records, which include AHRS information such as pitch, roll, and yaw (if a magnetic sensor is installed), vertical load factor (Z-direction), altitude, airspeed, and TE variometer data.

The feature is disabled by default and is only required for programs that support it. Its primary purpose is to enable applications such as a sky map, which is currently under testing.

AHRS RAW

[Disable]
[Enable]

Option to send as well the RAW AHRS gyro and accelerator data the follwing format.

!XCV,
G,<gx>,<gy>,<gz>, // gyro rotation deg/s
A,<ax>,<ay>,<az> // acceleration in multiple of G
*CRC // standard NMEA checksum
<CR><LF>

Battery Meter

Battery Type

[Cancel]
[LeadAcid]
[LiFePo4]

The battery type must be configured to align the battery meter with the voltage characteristics of the battery installed in your glider. Four reference voltages are defined for each battery type, representing the range from empty to full. Selecting a battery type presets these voltages according to the chosen type. Each voltage can also be adjusted individually if needed to match your specific battery.

Voltage definitions

Empty:  11.50 Volt
Critical: 11.75 Volt
Moderate: 12.00 Volt
Full:     12.8 Volt

Voltmeter Adjust

-0.00 %

12.75 Volt

This dialogue is intended for factory use only to precisely fine-tune the battery voltage measurement for maximum accuracy. At factory the voltmeter is calibrated. Without this adjustment, voltage measurement accuracy is approximately ±1%. Performing the calibration requires a multimeter to measure the voltage exactly an the cable ends where the variometer is connected.

This dialog is intended for configuring external devices connected to the XCVario, including FLARM units, navigation systems, secondary XCVario devices, radios, and other peripherals.

Precise knowledge of the connected devices and their respective interfaces enables the XCVario to automatically route data such as GPS position, ground speed, variometer data, radio control protocols, wind information, and additional system data to any peer that requires this information, e.g. a GPS fix to a navigation device.

Some of the devices may be configured automatically and will just appear in the list of devices as connected, others need manual attention. Further on this is the central to check on data streams and clarify a lot of questions that arrise so typically when adding avionics to the glider and not havin the final evidence on what is going on when trouble shooting.

Add Device

Device

[Anemoi]
[Flarm]
[Second XCV]
[Navi]
[Flarm Consumer]
[Flarm Download]
[Flarm Display]
[Radio Remote]
[KRT 2]
[Temp. Sensor]

Add one of the above devices to XCVario. The following settings flavour and interface depend on the selected device. Not all devices have a flavour nor can they connect to all interfaces. The offered choices are reduces to what is supported.

Flavor

[XCVario]
[Open-Vario]
[Borgelt]
[Cambridge]
[SeeYou]

Some devices like navigation devices (Navi) have different flavors. Depending on the kind of navigation device connected, a dedicated protocol might be needed and can be configured here.

Interface

[WiFi]
[S1 serial]
[S2 serial]
[BT serial]
[BT low energy]
{CAN bus]

Select here the interfacey where you want your device to be connected to. Not all devices support all interface, e.g. devices supporting only serial cable connection will offer only S1- or S2 serial here. Meanwhile S1- or S2 serial and CAN bus serial require a cable connection, BT and Wifi protocols are wireless connections over the air, and need bluetooth or Wifi coupling at your device.

Create it

[Cancel]
[Yes]

Finalize the creation of the selected device in your XCVario. Choosing [Yes] will save your configuration, else this will be canceled.

By default the following four devices are already setup in factory rollout configuration. The first is needed for a serial Flarm such as a classic Flarm device at S2 interface, and a Navi e.g. a mobile phone connected wireless.

NOTE: The device creation requires you to selected and actively confirm all the dialog items above. Once all settings of this dialog have been confirmed with a button press the creation of it will work.

Device List

An example of what the list of declared devices could look like.

Flarm> S1 
Flarm Consumer> S2
Flarm Cons.2> BTspp
Auto-connect> CAN
Navi> S2
Temp. Sensor> OneWire

Very likely a typical XCVNav equipped Cockpit that connects the XCSoar display directly to the S2 port of the variometer. It will thus receive GPS positions, traffic data, and all XCVario sensor data including pitch and bank angle from the AHRS module.
The second configured Flarm data receiver is certainly just a handy thing to download igc files direcly and wireless from the Flarm device to the smart phone after landing.

Device Attributes

An example of what the details of the Flarm device connected to S1 looks like.

S1 serial> 115200 baud 
Data Monitor
Remove device: cancel
Protocols on S1: NMEA Std, Garmin, Flarm; Flarm Download

The first entry gives access to most significantly the baud-rate setting, but as well to signaling scheme [Standard / TTL], Rx/Ty line swap, and the option to disable the Tx line.
The Data Monitor gives a live insight on the data stream. Sent and received amount of data is counted. The stream can be paused to be examined in detail.
Note: The Data Monitor can not be accessed while airborn.
The third entry gives the option to remove the device declaration.

The following lines list the instantiated parser plugin’s for the device. There is for every device a NMEA parser instance available, but also the option for an proprietary binary protocol parser. In the shown case the Flarm the connection is also able to handle the binary "Flarm Download" protocol and switch properly in-between them.

Note: There is no possibility to change a device declaration. It is just a very slim declaration and opportunity to store it permanently in flash memory. The straight way to change a device declaration is to delete it and re-add the device assiciated to another interface.

The XCVario has been kept simple in terms of installation and configuration. The installation in the cockpit is therefore easy.

Rear panel Connections

The connections are shown on the right. Except the first series out of 2020 that features only the left RJ45 connector the S1, all recent devices feature two electrical RJ45 connectors S1 and S1. The pin assignment, see the chapter on the RJ45 connectors. The interface S2 has standard IGC assignment, the connection of individual XCVario supplied devices such as the flap sensor or the magnetic sensor and can be done on S2 with 1:1 patch cables. The 80 mm variant has the same rear connections.

Caution: All other devices must be connected via the S2 extender/splitter. A direct connection of a Flarm, for example, to S2 can damage the CAN bus (from XCVario-22).

The supplied wiring harness may only be connected to the S1 socket with the “Vario” labeled plug. Do not connect the Vario plug to the S2 socket either. If voltage is present, this can damage the temperature sensor in the cable on older revisions of the wiring harness.

Also, do not connect the end of the wiring harness that is labeled “Flarm” to the XCVario, this is intended for a Flarm IGC port and should remain unused if Flarm is not used.

Please also note that a possible defect caused by demonstrably faulty wiring is not covered by the warranty.

Pneumatic connections

The pressures required for the XCVario can be connected to the instrument hoses of the mechanical instruments using 6 mm T- or Y-pieces. If these connections are not already available from a previous Vario, the instrument hose can be cut at a suitable point and the connection for the Vario can be made using a T-piece.

Note: A compensation vessel as usually equipped in older installations is NOT needed. Do not connect this to any of the pressure hoses of the XCVario.

You will need:

TE:  TE-probe pressure

ST:  Static pressure ( = Static )

PI:  Total Pressure ( = Pitot = overall pressure )

The pressures are usually hosed by the manufacturer behind the instrument panel, and are either already routed there, and can be taken over 1:1 from from a previous device, or can be taken from mechanical instruments using a simple pneumatic T-piece. The pressures for PI and ST are on the airspeed indicator, the TE pressure usually on a mechanical variometer.

Electrical connections

Micro USB

The device is programmed for the first time in the factory via the Micro USB-B connector on the sensor circuit board and is only accessible in the 20 and 21 series when the cover is removed. From the 22 series (57 mm), the USB-B connector is accessible on the top of the device, the opening is sealed with a sticker at the factory. The cable can only plugged in one position, the wider section of the connector is towards the front.
The device can be connected to a PC via USB for diagnostics and can also be supplied with power via the PC. In order to establish contact with the serial interface of the ESP32, drivers for the serial USB converter chip CH340G may be required.
The connection is not required for operation as a variometer, nor for the OTA software update, which takes place via the ESP32 OTA WiFi connection.

Audio Output

A 3.5mm stereo jack offers an external output for the audio signal of the variometer. Either your own external speaker can be connected to it, or an audio input of a radio device can be used. Normally, the internal loudspeaker of the variometer is sufficient, but it can make sense to be able to hear the signal there, e.g. when operating with headsets, or to connect an external loudspeaker closer to the head in loud cockpits. The internal speaker switches off if an external audio device is plugged in.

Abbildung 1: Audio Stecker The picture on the right shows the necessary audio plug, it is a standard 3.5 mm jack plug with tip, ring, sleeve (TRS), i.e. 3 connections. In the model in the drawing on the right, connector 1 is the tip, 2 is the ring, and 3 is the sleeve. The speaker is connected to connection 1 and 3. Port 2 remains unassigned (NC). If in doubt, measure the connector with a multimeter. The speaker must be connected between the tip and the ground pin.

On the Vario side, the mono audio signal is also applied to connection 2 (ring), so it is not possible to use a mono jack plug (TS) with devices from the 2020 and some 2021 series, as this does not have an isolated ring between connection 2 and 3, and connects connection 2 to ground. From the 4/2021 series, i.e. devices from September 2021, the Vario signal is only output on connection 1, the alternative use of a mono plug is then possible.

RJ45 connector S1

The standard shippment includes a cable tree the XCVario FLARM cable that features a ready-made temperature sensor, a plug for standard applications (standard IGC assignment, e.g. as with most FLARMs and loggers), and an open cable end for a S2F switch. The cable can also be obtained from the shop.

Caution: The assignment at connection S1 with S2F switch and temperature sensor does not have an IGC assignment but is XCVario-specific and different from S2. The XCVario FLARM cable converts the assignment on the S1 appropriately, so that the IGC standard assignment (RJ45) required for the FLARM is available at the end of the FLARM cable. The RJ45 socket is shown in the figure above in a plan view from the rear. Pin 1 is therefore on the far left. The minimum connections required to operate the device in its basic function are shown in bold.

Interface S1

Temperature sensor

The temperature sensor must be connected to the three pins 5, 6 and 7 provided with the RJ45 cable of the corresponding color. The temperature sensor is part of the FLARM cable.
The temperature sensor is a ready-made Dallas DS18B20 sensor with a waterproof casing and a 1 meter long cable. The sensor has three colored lines, which are usually coded with the colors red, yellow and black. If you use your own sensor, the manufacturer’s instructions must be observed.

The shipped cables comes with this sensors or can be ordered in the shop. To measure the outside temperature, the sensor is to be placed e.g. in the front vent.
This can also be done in the ventilation pipe if available. In this case, a small slit is cut with a cutter knife, the temperature sensor is pushed in and sealed with aluminum adhesive tape or silicone, for example.

Speed to Fly switch:

The vario/speed command switch is to be connected to pin 4 of the RJ45 and to ground pin 8. If the switch is closed, target travel is selected. The function can also be changed in the setup, i.e. when the switch is closed, Vario mode is selected.

S1 Serial (FLARM plug)

The FLARM is the standard configuration for the Interface S1 and can be connected to the XCVario with the standard FLARM cable at FLARM plug labeled ending. With the simple FLARM cable, only the direction FLARM is connected to XCVario (Series 20), i.e. only pin 4 in FCC numbering. These cables are no longer offered. The bidirectional FLARM cable is required for bidirectional communication with the FLARM (standard from series 2021). This enables e.g. the flight declaration in FLARM via the navigation system (e.g. XCSoar).
Below is the assignment at the FLARM end of the standard cable, the minimum connections required for receiving FLARM data are shown in bold.

RJ45 connector S2

The hardware has the second electrical RJ45 connector “S2” with standard IGC pins for the serial port, plus an additional input/output for a flap sensor and for a CAN bus (2). It is recommended to use the S2 extender to connect various gadgets to the S2 connector. A single gadget such as a CAN Magnet-Sensor, a second XCVario or a flap sensor can be connected directly.

Interface S2

S2 Serial (Device)

Standard configuration for S2 is a serial device such as Kobo, serial OpenVario, a radio or else. The Pins are according to the IGC standard, hence a 1:1 cable is only recommended for devices that do not have any connection on the other pin’s except GND and on power pin. Other devices shall be connected via the S2 Extender/Splitter that only connects the serial pins, power and GND.

Analog Input (flap sensor)

Any XCVario with an S2 interface features an analog input for various functions. The major application of this input is usage with the flap sensor. Its also usable as a gear alarm input alternatively (see gear warning chapter).

The flap sensor is available in the shop, and is to be mounted in a suitable position near the flap linkage and must be fixed to the fuselage wall with an appropriate holder e.g. with 5-minute epoxy, and attached to the flap in order to get a rotation of the shaft by an adhesive joint on the flap linkage. Under no circumstances should the linkage be drilled into.

Note: The analog input can only be used in Bluetooth mode due to a limitation in the first series 2021. For applications that require WiFi mode, the hardware will be required from March 2021.

CAN Bus

The XCVario-22 hardware features a CAN bus interface as an option for data transmission to a second device and to connect additional hardware such as the CAN magnet sensor.

External Devices

OpenVario

The OpenVario (including the Stefly OpenVario) can be connected directly to the XCVario via ttyS1 or ttyS2 using either a 1:1 cable at S2 or the standard FLARM cable at S1. In this configuration, the XCVario receives its data directly from the OpenVario.

Power considerations:

• Supplying power from the XCVario to the OpenVario is not recommended, due to the OpenVario’s larger display and higher power consumption. It is better to let the OpenVario act as the power source.
• In this setup, the XCVario’s power input at connector S1 remains unused.
• If you prefer to power the devices separately—for example, to switch them off individually in a power shortage or to protect each device with its own fuse—you must disconnect the +12 V line in the patch cable and supply the XCVario independently at S1.

Alternative connection via ttyS0 on the OpenVario:

• Connect the RX, TX, and GND pins from the OpenVario Sub-D connector to the serial interface of the XCVario at S1 or S2.
• On the variometer, set RX/TX pins to “Swapped” under … Navi → S[1|2] serial → Swap RX/TX. The default is Normal.
• Ensure the baud rate matches on both devices. All other serial interface settings remain unchanged.

FLARM integration:

• The FLARM can be plugged directly into the OpenVario, or forwarded via the XCVario.
• All routing requiers no configuration and is done automatically.
• The pins shown in bold represent the minimum required connections to display FLARM data on the OpenVario.

• For connecting to the OpenVario (OV), XCVario recommends using a standard RJ45 (8P8C) cable, i.e., 8 pins with 8 connections, wired 1:1, as commonly used in network technology. You can search for a flexible network cable on Google or Amazon.
• Typically, a 0.5 m cable is sufficient between the two devices on the instrument panel.

Important notes for wiring:

• When connecting an XCVario-22 to the OV, the S2 splitter is always required. This is because the OV also supplies +12 V on pin 7, and connecting directly could damage the CAN bus (no guarantee if an OV is connected directly to S2). The OV should be connected to the RS232 splitter port.
• If the +12 V supply to the OV should be completely suppressed, insert the Y-piece and remove both jumpers for pins 7 and 8. This ensures only the data connection is established between the two devices.

Double-seater configuration (two XCVarios and two OVs):

• The cables only need to be connected to the front device. Data from the front device can be forwarded to the rear device via the CAN bus.
• Connect the splitter to S2 on the front device. The patch cable from the front device to the splitter should not exceed 50 cm; shorter cables reduce the risk of interference.
• The rear device can then be connected to the CAN port of the splitter via S2 using a patch cable of suitable length. In this setup, the rear device is powered via the patch cable from the front device, so no separate power wiring is needed.

Cable and sensor considerations:

• Using an additional 1:1 RJ45 Y-piece on the CAN bus after the splitter, a CAN magnetic sensor can also be integrated.
• Use flexible cables to prevent stress on the plugs. Keep them as short as necessary.
• Additional sensors (e.g., flap sensors) can be connected to the splitter.

KRT2

XCVario Interface Setup

The connection to the radio of the type KRT2 makes sense if your navigation device has a driver for it (XCSoar and LK8000 do so), can be established by a serial connection with any XCVario model that features a S2 interface on its back (all do except XCVario 20). The baud rate should be set to 9600 baud (the only one KRT2 supports).

Attention: To enable the “Navi” you are useing to benefit from the attached KRT2 you have to configure a peer device called Radio remote. configure the Radio remote to the same interface as the Navi and thus protocol and routing will be enabled to control the KRT2.

Wiring KRT2

To connect the serial interface of your KRT2 make the connection from S2 pin 3 and 4 to the corresponding serial RX/TX of the KRT2, it is best to solder it there to the existing KRT2 Sub-D connector, to pin 2 and 13, crossed, i.e. RX from vario to TX of radio and vice versa as follows:

XCV 3 (TX)  <-> 13 KRT2 (RX)
XCV 4 (RX)  <->  2 KRT2 (TX Remote)
XCV 1 (GND) <->  1 KRT2 (GND)

The software connection with the XCVario is only possible in WiFi mode (which may have a few disadvantages, see the Wireless LAN manual), via the TCP client with port 8882. Configure the driver for the KRT2 in the navigation system there.

Unfortunately, a connection via Bluetooth is not possible aside of XCVario because XCSoar can only configure one driver for an interface and only one Bluetooth connection to a device is possible. Alternatively, to stay with Bluetooth, there is the option of connecting the KRT2 to the XCSoar as a separate BT device via an external Bluetooth bridge. BT bridges are available from many manufacturers, or here in the shop: https://xcvario.com/product/serial-bluetooth-WiFi-adapter/

Using External Audio from KRT2

The XCVario has a highly efficient digital amplifier with pulse-width modulation that does not relate directly to ground, but rather emits a symmetrical signal (2). If you connect both poles of the audio out to the asymmetrical KRT2 radio input, one output suffers a short circuit to ground, what even can cause damage of the audio driver stage in prolonged operation, and high frequent noise. Do also not try to connect just one pin, and leave the other open, there will be noise as this is an invitation for disruptions: a ground loop across the supply lines. To get from a symmetrical output to an asymmetrical input, a small audio isolation transformer helps, which is available in small format for little money, for example here: https://www.ebay.de/itm/394922853247. Or here with cable ends: https://www.thomann.de/de/neutrik_nte_4_audio_uebertrager.htm . One side of the transformer is then connected to the two lines of the jack on the XCVario, e.g. on the Neutrik Yellow/White and the other side is between pin 5 and GND on the KRT2 (red/black).

ATR 833 Radio

The pin assignments and connections on the ATR833 are as follows, the corresponding driver is labeled ATR833 in XCSoar.

XCV 3 green/white (TX)   <->  9  ATR833 (Data RX)
XCV 4 blue (RX)          <-> 22  ATR 833 (Data TX)
XCV 1 orange/white (GND) <-> 25  ATR 833 (GND)

ECW100 (Flarm/GPS)

The ECW100 Flarm might be connected to the FLARM labled plug ending at S1 cable tree to the PC labled connector at ECW100. If a driver is needed for flight upload, FLARM is to be selected. For the GPS data there no driver required, GPS is standard NMEA and processed be XCSoar in any case. The connections are as follows:

XCV 3 green/white (TX)  <-> 11  ECW100 (RX)        (3 PC RS232)      
XCV 4 blue (RX)          <-> 12  ECW100 (TX)        (2 PC RS232) 
XCV 1 orange/white (GND) <-> 13  ECW 100 (GND)    (5 PC RS232)    

Source: Installationshandbuch ECW100 V1.6 pdf

Power Supply

The power supply is connected to the vehicle electrical system. A single fuse for a variometer is not mandatory for gliders, but is recommended. The wiring can be done with copper strands from 0.14 mm², 0.25 mm² is recommended. Alternatively, the XCVario can be connected in parallel to another device that is fused with at least 0.5, better 1 ampere. The device must be protected because the plug and cable are not designed for higher currents. The device tolerates voltages in the range of 5-28 volts, a supply of 12 volts is ideal. If the device is operated without any protection plus an external short circuit, e.g. at S2, internal damage is to be expected which is not covered by the guarantee. It is therefore essential to also secure it on the laboratory bench for test purposes.
The XCVario is protected against polarity reversal and is internally protected against transient overvoltages such as ESD discharges and induction peaks when starting. In general, the avionics should be left switched off when starting, if it cannot be avoided, e.g. when starting during the flight, you have to rely on the overvoltage protection.

Vario / Speed to Fly Switch

The vario S2F switch can be attached to the stick or in the instrument panel. Its second pin must be connected to ground (negative pole supply). With ground contact at pin 4, the vario is in speed to fly mode, with an open switch in vario mode. The speed command display is constantly in operation, but the tone generator changes to speed command as input. A button can also be used instead of a switch. In this case, the switch type must be set accordingly in the setup.
The switch is not absolutely necessary, as it is possible to automatically switch over to S2F from a certain speed. This can be achieved in the Audio/AudioMode menu with the “Autospeed” setting. The “AutoSpeed” is the speed above which the variometer switches to the S2F mode.

Serial RS232 Connections

The RS232 interface’s at the connectors S1 and S2 are used to connect a device without wireless (Bluetooth or WiFi) support, e.g. legacy OpenVario, older Kobo, or to connect a serial FLARM IGC port to the XCVario.
With a bidirectional cable (RX and TX direction connected), a flight task can also be declared in FLARM, the FLARM can be managed from your Navi App, or a flight download can be carried out. For the cable, see the description in the chapter on cable assembly. The FLARM application is preset, no settings need to be made on the serial interface in the setup.
In principle, only one device can be connected to one serial interface port. This is a limitation coming from the RS232 protocol. Analogy: One teacher can talk to multiple students at the same time, but only one student may as a question. There are tricks to connect multiple devices to one RS232 port, e.g. the second device does not have wired the transmission direction (TX) towards its peer, it can be connected in parallel. This may require special cables or adapters which not all have connections and do not connect the TX wire from the peer.
In the case of an OpenVario on the serial interface, the “XCVario” data is needed on the serial interface, which can be set in the setup of the “RS232 Interface S1” under “TX Routing”. More information in the setup description.

Pinout in IGC- and FCC Standard’s

The RJ45 socket pins in this document are numbered according to the international FCC standard, which is the numbering convention most commonly used worldwide. In contrast, the IGC (International Gliding Commission) standard for logger interfaces uses a reversed pin numbering scheme.
The XCVario S2 interface and the S1 FLARM plug follow the IGC standard exactly.
In this document, the primary pin numbers are given according to the FCC standard, while the corresponding IGC pin numbers are optionally shown in an additional column for comparison.

The left figure shows the FCC standard, in which the first pin is identified as pin 8 when viewing the RJ45 plug from the front.
The figure on the right shows the IGC standard with reversed pin numbering (source: Technical Specification for IGC-approved GNSS Flight Recorders – Second Edition with Amendment 6, 25 November 2020). In this case, numbering starts on the left-hand side of the connector with pin 1.

When checking the pin assignment of a device, it is essential to always verify the pin numbers against the corresponding diagram and viewing direction. According to the IGC standard, the numbering of the RJ45 plug (right) is correct. However, the numbering of the RJ45 socket (left) is incorrect. The table applies only to the plug as viewed from the front, with the cable pointing away from the observer, and is therefore not valid for the socket.
This can easily be verified: if the RJ45 plug shown were inserted into the corresponding socket, pin 8 of the plug would mate with pin 1 of the socket, which is clearly incorrect.
In summary, the plug is numbered correctly, while the socket is numbered incorrectly; the pins on the underside of the socket should be labeled 7 and 8.
Comparison of the pin numbers of the FCC and the (wrong) IGC standard:

Installation and drilling plan

Mechanical Installation Specifications

The 57 mm variant (left) conforms to the standard aviation cutout for 57 mm instruments. The 80 mm variant corresponds to the standard mounting dimensions for 80 mm panel instruments. Mounting is performed using four M4 screws. The panel holes should be drilled to a minimum diameter of 4.5 mm.

⚠️ Important: The mounting screws must not penetrate more than 10 mm into the device housing. Exceeding this limit may damage internal components, and proper operation cannot be guaranteed.
Recommended screw lengths for a panel thickness between 1 and 3 mm is M4 × 10 mm.

Mounting hole circle diameters:
80 mm device: 89.1 mm
57 mm device: 66.7 mm
In the case of particularly thick instrument panels with a thickness of more than 2 mm, a small, preferably semi-circular niche with a width of 2 mm and a height of 14 mm must be created halfway up the side for the rotary button. Normally this is not necessary, since standard panels are approx. 2 mm thick.

The 57mm device was developed for a 57mm bore and is optimally adapted for it. The 80mm device is more suitable for an 80 mm cut-out.
The installation of the 57 mm device in an 80 mm cut-out is possible using our cover as below.

Drawing of the front part

The exact dimensions of the front part as interface to the instrument panel is shown below. The device is fully symmetrical and can be mounted TopDown im case the rotary button is preferred on the right side.

(1) From 2021 series hardware

(2) From series 2021/3 (October 21)

(3) 2020 series with 1.2 W power

The variometer itself does not require any further maintenance, since a regular leak test of the instrumentation is normally required as part of the maintenance program (IHP/AMP) of the aircraft. This is usually to be carried out at least once a year. This also covers the test of the variometer. Of course, a test is carried out in the factory, but this does not include the instrument hoses on the aircraft, as well as their aging and the aging of O-rings in the variometer itself. If the test for leaks is missing in the program, a corresponding supplement should be made.

Warranty and Returns

The manufacturer provides a two-year warranty for the vario from the date of purchase, covering labor and material costs for repairs.
Within this warranty period, any components that fail under normal operating conditions will be repaired or replaced free of charge, provided that the device is returned to the manufacturer postage paid by the customer.

The warranty does not cover damage resulting from:

• misuse or improper operation
• abuse or accidents
• unauthorized modifications or repairs
• insufficient or esp. improper maintenance
• proven incorrect or faulty wiring

Issues that can be resolved through a software update performed by the user are explicitly excluded from warranty coverage.

In accordance with the German Civil Code (BGB), the buyer has the right to withdraw from the purchase within 14 days of the purchase date.
In such cases, the device and all included accessories must be returned to the address from which they were delivered. Return shipping costs are borne by the buyer.

For each instrument, if the equipment is part of the minimum equipment list or requires approval, it may only be installed if the supplier or manufacturer provides a document on the proper check for compliance with the respective specification of the individual piece of equipment, area of ​​EASA this is usually the EASA Form One.

For all other equipment, as well as for standard parts, a corresponding examination and documentation of the same is not required (e.g. variometer, final approach computer, flight data recording devices, navigation computer, additional antennas, batteries, cameras, additional pressure probes, mosquito cleaning systems, etc.). This is regulated in detail by EASA in AMC 21.A.303(c) 2, with the following wording:

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AMC 21.A.303(c) Standard Parts

1. In this context a part is considered as a ‘standard part’ where it is designated as such by the design approval holder responsible for the product, part or appliance, in which the part is intended to be used. In order to be considered a ‘standard part’, all design, manufacturing, inspection data and marking requirements necessary to demonstrate conformity of that part should be in the public domain and published or established as part of officially recognized Standards, or
2. For sailplanes and powered sailplanes, where it is a non-required instrument and/or equipment certified under the provision of CS 22.1301(b), if that instrument or equipment, when installed, functioning, functioning improperly or not functioning at all, does not in itself, or by its effect upon the sailplane and its operation, constitute a safety hazard.

‘Required’ in the term ‘non-required’ as used above means required by the applicable certification specifications (CS 22.1303, 22.1305 and 22.1307) or required by the relevant operating regulations and the applicable Rules of the Air or as required by Air Traffic Management (e.g. a transponder in certain controlled airspace).

Examples of equipment which can be considered standard parts are electrical variometers, bank/slip indicators ball type, total energy probes, capacity bottles (for variometers), final glide calculators, navigation computers, data logger / barograph / turnpoint camera, bug-wipers and anti-collision systems. Equipment which must be approved in accordance to the certification specifications shall comply with the applicable ETSO or equivalent and is not considered a standard part (e.g. oxygen equipment).

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This means that no EASA Form One is required for the vario, and it may be installed without additional certification.

• The system must be checked for leaks.

• The aircraft’s equipment list must be updated accordingly.

• If the impact of the I-board’s mass on the center of gravity cannot be reliably calculated, the aircraft must be weighed, and any resulting change must be approved.

With the purchase of the device, the customer agrees that no liability for any direct or indirect damage, claims for damages or consequential damages of any kind and on any legal basis arising from the use of the device.

The device is a purely cross-country flight tactical device, so it is not part of the required instrumentation for gliders, and in case of doubt it must not be used as the primary source for controlling the aircraft, especially in critical flight phases. The target instrumentation is to be used for this. The device therefore does not require any FAA or EASA approval.