Borgelt B500 VE variometer system                       16 December 2008


The full function variometer system for cross country and contest sailplane pilots. Also incorporates a simple navigation, glide and wind computer as well as data output to PDA's or the Borgelt B2500 Advanced flight computer.

Download B500 manual as PDF file: B500man.pdf

B500  VE (Variometer Engine)  with


Glareshield Control and Display unit ( B500 GCD)


GPS unit for B500 VE (B500 GPS)


System components are described below.




B500  VE (Variometer Engine)


The B500 VE replaces the B50 with the addition of new technology and functions.


The B500 VE consists of the B500 variometer unit, The B500 Glareshield Controller and Display unit (GCD) and the B500 HP - GPS.


B500 HP - GPS


A small GPS unit is part of the B500 VE and plugs in to a connector at the rear of the  B500 VE. This GPS uses the latest low power technology and draws less than 30mA at 12 volts as well as providing genuine 4Hz fixes. The current version is a 50 channel receiver for fast first fix and tenancious ability to hang on and re-acquire signals.

Use of our own dedicated GPS avoids compatibility problems that are all too often present when interfacing one of the numerous commercial GPS units or loggers. The high quality data from the GPS, not available from loggers or commercial GPS units, may also be used in future enhancements of the B500 system.


B500 variometer unit


Nearly identical to the B400 AV in front panel appearance the B500 variometer unit is slightly longer at 115mm including connectors and is also available in 57mm or 80mm sizes. An airspeed sensor is included in the B500 which enables calculation and display of advanced variometer functions.

The B500 uses surface mount technology in the electronics and the variometer display is by a small stepper motor driven pointer. This provides the display with far better resolution and contrast than the LCD type pointers under all the changing lighting conditions typical in a circling sailplane. The display resolution is around 1/40 of a knot. This means a far smoother indication and much faster recognition of which way the pointer is moving particularly if the lift is weak. This is nearly 20 times the resolution of typical LCD pointers.


The vario display and climb mode audio are the same as the B400 AV with red and green LEDs near the “zero” point of the variometer. When climbing, the green LED is ON when the variometer is above the running 20 second value . In cruise the red and green LED’s indicate when the airmass is rising or sinking relative to still air.

The climb audio operates as follows:  At -10 knots (-5 m/s) the audio begins with clicks which become closer together as the sink decreases and then become a rising tone with the tone being chopped in lift. When the lift is below the running twenty second average the beeps are 70 on : 30 off, when the lift is above the running average the tone is 50 : 50. This lets you know immediately which side of the thermal is improving your rate of climb. This feature may be disabled and the audio operated in “classic “ 50 : 50 beep mode.

The audio is easily able to be customised. Various options are available including no sound in sink when in climb mode and 50 : 50 beeps when climbing regardless of whether the the climb rate is above or below the running average.


In cruise mode the vario becomes optionally TE vario, netto or Relative netto. Two blue LED’s and two amber LED’s provide the speed command display and the “fly faster” and “fly slower” sounds are the same as in the B50  - two alternating tones for “fly slower” and two very rapidly alternating tones for “fly faster”. There is a silent  zone around the correct speed to fly and when the relative vario goes above the Macready setting the sound changes to the normal TE vario.


The audio is muted and restored by pressing the push button in the lower left mounting screw position.


The B500 has a two channel audio and is supplied with left and right speakers. The audio sounds can be  switched depending on various circumstances. When thermalling the sound is switched to one speaker when the circle should be opened in that direction. When cruising the speed command sounds come from the side where the next turnpoint lies.

Various B500 functions are customisable by connecting the unit to a PC, including the audio silent zone. Software updates are accomplished the same way.


B500 Glareshield Controller/Display (B500 GCD). Now with Mini SD card slot for GCD program upgrades, B500 settings and turnpoint database memory.

The GCD is a a small unit 30mm high by 80mm wide and only 30mm deep which is designed to mount under or in the lip of the instrument panel cover or at the top of the instrument panel. This keeps it conveniently in the pilot's line of sight, even when adjusting control settings. The is a slot under the GCD for a mini SD card. GCD program updates, all the B500 settings and up to 10 turnpoint databases are able to be loaded on the card.

As the B500 main unit operating software has been stable for a long time now, it should normally never be necessary to bring a PC to the aircraft.


The controls are closer to the pilot  and the display is very close to his line of sight, assisting with orientation and lookout. By separating it from the variometer the variometer pointer does not obscure its displays.

It is supplied with a 0.5m  cable with plug  which connects to the B500 variometer unit by plugging it in to a socket on the back of the instrument.


The B500 GCD has a push button top left and under it a rotary encoder with push button action and the rest of the area is occupied by a 122 x 32 graphics LCD with display area measuring 60.5 x 19 mm.

The push button changes the display page and the rotary encoder push button moves the cursor to the variable the pilot wishes to change whereupon rotating the encoder  changes the variable and it is immediately active. There is no “enter” function.


For example,  on the main page the Macready setting is the only variable so just rotating the encoder is all that is required to change this. To change bugs, ballast or volume press and hold the page button to get to the setup pages where these are displayed press the encoder knob to move the cursor to , for example, “Ballast” and then rotate the encoder to change the ballast setting.


The B500 GCD receives GPS and air data from the B500 variometer unit/B500 GPS and in addition to the display of the average rates of climb the B500 is controlled by the GCD and the pilot can enter Macready, bugs contamination, ballast state, control B500 audio volume and balance and in addition a simple GPS navigation display with turnpoint database, wind  and final glide computer can be shown.

This makes the instrument ideal for club gliders while the B500 also supplies RS 232 serial, air and GPS data to any desired full function glide and navigation computer such as the Borgelt B2500 or any of the PDA type devices. *(see PDA-PS later)


While in theory the B500 could be controlled by a PDA or other air data computer such as the Borgelt B2500,  using the GCD keeps the variometer “housekeeping” functions separate from the glide computer which simply picks up these changes in the serial data stream going to it from the B500 VE. This simplifies both the control of the variometer and of the glide computer.


Total energy is by probe for the same reasons as with the B400 AV. TE probes provide by far the best and most reliable TE compensation. Excellent TE probes are available from Borgelt Instruments.

The B500 VE has an Outside Air Temperature probe and the temperature is displayed on the GCD. The OAT is used in internal air data calculations when present.


GPS and Air data is supplied by the B500 to external computers and navigation devices by serial messages at 1 Hz in the same manner as done by the B50. The decode of this message is available on the Borgelt Instruments website under “manuals- B50 - DDM”.



The B500 VE is then the “variometer engine” for these systems.



Image shows PDA_PS with DB9 for B2500, RJ connector for B500, panel mount data control switches and serial port for B500/B2500 software maintenance.

PDA connector and logger /FLARM connectors not visible (under Nomex cover)

For those using a PDA(palmtop computer) for a glide computer there is an optional PDA power supply(PDA-PS) that plugs in to the B500 and provides 5 volt power  and data  to the PDA. There is also a connection for a logger on this  unit, connection for a FLARM (or second logger) and two panel mountable switches which allows connection of the data to/from logger/FLARM direct to the PDA for declarations and optionally allows selection of Logger/FLARM GPS or B500 air data/GPS for flight information.

Installation is simplified as 12 volt power must be supplied only to the B500 and the PDA-PS distributes power and data to and from the logger, FLARM and PDA. 

The PDA-PS also supplies power and data to a B2500 glide computer as well as to a PDA.

In addition, when fitted with the optional combiner board, the PDA_PS substitutes the logger or FLARM (whichever is selected) data for the B500 GPS data. If logger or FLARM data is not available B500 GPS data is supplied. This means that logger pressure altitude or FLARM aircraft data and pressure altitude may be passed to the PDA. To cope with the large quantity of data in some messages, input baud rates higher than 4800 are allowed and the data is passed to the PDA at this higher rate. Autobauding is used so this is transparent to the user.

Other variometer systems may also use the PDA_PS for this purpose. Check with us for compatibility details.