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TruTrak ADI Pilot II help

Bud K

Well Known Member
I just bought a RV-4 with the subject autopilot installed. It was connected to a Garmin 396 GPS, which did not come with the plane. According to the Users Manual, the DG is supposed to begin displaying heading after the aircraft has a ground speed of approx 15 knots. Mine does not. It simply reads '0' when I engage it. It seems to be entering 'Gyro Back-up mode' and rotating the right knob selects the bank angle.

I have read the manual but I can find nothing to address this issue. Maybe I am missing something. I flew 400 hours behind another TruTrak product and loved the support when issues arose. Sure do miss hopping down to Springdale to get issues worked out.
 
It needs a GPS source, it does not have one of its own. A RS-322 serial input should have been wired to Pin 17 (I think - page 11 of the manual that I have).
 
Without a GPS source to provide track or heading information it will fall back to the bank mode that you are seeing.

Note the heading is a GPS track heading not a magnetic heading.

You will need a GPS that provides serial output to make this set up work.
 
396 will work great! Make sure the serial output is turned on in the 396 and that the baud rate for both match (typically 4800 on handheld GPS). PM me if you need direct help! Oh, also make sure that you have the power/data cable on the 396 and the autopilot is connected to the blue wire.
 
I have the same problem of connecting a gps to this autopilot.
I have got a Garmin pilot 3 but it does not fix due to some issue with the date.
Update problem that I am not able to solve.
Would it be possible to use any of the new GPS antennas from Beitian for exemple ?
 
make sure that you don't just have the serial wire connected, there must be a ground connection as well.

Not sure why the date would have anything to do with serial connection working or not. If the GPS has a fix, the baud rate is correct, and there is a common ground, it should work.
 
A wrong date prevents the GPS to work.
I found a software that should correct the bug but I am unable to connect my PC to the GPS. Even Garminexpress does not install on my PC.

Has anyone tried to connect a simple GPS receiver to a Trutrak AP ?
 
A wrong date prevents the GPS to work.
I found a software that should correct the bug but I am unable to connect my PC to the GPS. Even Garminexpress does not install on my PC.

Has anyone tried to connect a simple GPS receiver to a Trutrak AP ?

Michel, having the right date and time is critical to establishing a GPS receiver position. It is so critical that a part of a device start includes listening to a standard carrier frequency to establish the date and time of the first bird it hears. As it hears more satellites it uses logic to compute the exact time, normally starts after hearing 4 satellites. Time as you know helps to drive the accuracy. The further you move it from its home position the longer it will take to acquire a signal and date time group. The home position is the location the GPS believes it is at when it starts for the first time or after a complete battery drain. Even the worst receivers have locked my position in under 10 mins from a cold boot in some of the most remote places on this planet.

Andrew can correct me, but from a serial standpoint the RMB and RMC messages are critical to be able to use the Autopilot. These are basically position and waypoint messages. You will not only need a GPS receiver that has the ability to generate the messages using NEMA 183 but also the ability to allow you to set flight plan (waypoints) to allow the AP to fly to the waypoint.
 
GPRMC is position, veloticy, and time - this is needed for the AP to have the track selector.

GPRMB is navigation data - this is needed for the AP to be able to follow a flight plan.

technically speaking, GPRMB is not needed for the track selector to work...so a simple puck GPS will still give the AP GPRMC and enable the track selector to work (We used to offer the GPS 35 for this exact purpose).
 
Thanks Andrew and CTH6.
However, one more question, GPS 35 is USB plugged and then some USB to RS232 converter has to be interfaced between the GPS and the AP.
If GPS 35 is Garmin ETREX 35.
Michel
 
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Without a GPS source to provide track or heading information it will fall back to the bank mode that you are seeing.

Note the heading is a GPS track heading not a magnetic heading.

You will need a GPS that provides serial output to make this set up work.

FYI. My TruTrak a/p is coupled with my Aera 660. I was unsure what heading type was displayed on the a/p. So I scrolled through the various “data boxes” on the Aera 660 and found the only data box exactly matching the a/p display was “Gnd Trk (mag)”. So, it is my impression that the a/p displays Ground Track (mag) when coupled to my GPS.
 
I believe the Garmin 18X-5hz gps will work out of the box.
BUT, check for proper input voltage, it requires 4 - 5.5 vdc.
Connect the gps #4, white, transmit data, wire to the ADI Pilot II pin 17, Primary Serial Input. Also be sure of a common ground between the gps and the autopilot.
Yes the Garmin gps can be reconfigured if needed. I needed an adapter to connect it to a laptop serial port, and software to read/configure the gps.
The adapter was made by Keyspan, the software came from Garmin.

Gary
 
Gary,
I have connected the GPS 18X LVC to the ADI.
Out of the box, the working is fine.
Of course the GPS needs one 5V supply voltage.
Thanks once more.
Michel
 
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