Trim & Flap Position Readings on EFIS

[Marc Ausman]

Often builders want to have the flap and trim position displayed on the EFIS as well as the VP system. This describes how to do this using Ray Allen trim servos.

The trim and flap position sensors have three wires that together provide feedback:
white/blue - +2.5v reference voltage. Some EFIS systems use +10v, but the VP uses 2.5v.
white/orange - this gets wired to ground.
white/green - analog position feedback. This voltage varies as the position of the trim/flap sensor moves.

The VP system provides the reference voltage and the ground. Some EFIS systems provide this too. Do not wire these from the EFIS. Only wire them from the VP Control Unit.

The flap and trim motors should be wired to the VP Control Unit as per standard instructions.

Be sure to calibrate the VP first, then calibrate the EFIS.

For the VP-100/200:
Wire the trim normally as per the VP installation instructions. Then, splice into the position feedback wire (white/grn) on the control unit - J7 pin 5 or pin 26 or pin 28. For each position sensor you want displayed on the EFIS, run a wire from the position input on the CU to the EFIS input. Then calibrate the EFIS so it reads correctly throughout the travel.

For the VP-50:
Wire the trim normally as per the VP installation instructions. Then, splice into the position feedback wire (white/grn) on the control unit - J8 pin 17 or pin 33. For each position sensor you want displayed on the EFIS, run a wire from the position input on the CU to the EFIS input. Then calibrate the EFIS so it reads correctly throughout the travel.

[Marc Ausman]

The VP-200 now (as of software v20.6) outputs trim, flap position as well as mode and amps over an RS-232 serial line which can be read by certain EFIS systems. More information here: http://www.verticalpower.com/forums/...read.php?t=723

[Marc Ausman]

The VP-X outputs the trim and flap position to the EFIS, along with the status (and current draw) for each circuit. As well as total current draw.

[Marc Ausman]

To clarify, if you're using the VP-X with an EFIS, you do not need to wire anything (trim and flaps and even a shunt) to the analog inputs on the EFIS. On the EFIS, the trim and flap inputs come from the serial data line from the VP-X. The tim and flap positions are calibrated and don't need any further calibration in the EFIS.

[Marc Ausman]

If you are using a trim motor that does not have a position sensor built in, please see: http://www.verticalpower.com/forums/...read.php?t=766