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View Full Version : afs-xtrans and/or SV-261 communication problem?



jcaplins
11-30-2014, 06:57 PM
Is the "AFS-Xpndr" the same as the "SV-261", mode S transponder?

I purchased the "AFS-XPNDR", which appears to be a Trigg TT22. All the AFS install documents appear to refer to the SV-261. Of coarse the SV-261 looks a lot like the trigg as well. (I believe the label on mine says "trigg TT22", will need to double check when I go back to the hangar.)
The trigg TT22 install documents are different than the SV-261.

I've connected mine as a SV-261 and I do not get any communication with the AF5600.

For SV-261 (and currently wired):
pin 1 - loop, connect to pin 2
pin 2 - loop, connect to pin 1
pin 5 - serial RX
pin 7 - serial TX
pin 12 - loop, connect to pin 13
pin 13 - loop, connect to pin 12
pin 14 - ground
pin 15 - power


From Trigg TT22 install document:
pin 1 - ground
pin 2 - TMAP1A (possibly serial 1)
pin 3 - TMAP1B (possibly serial 1)
pin 8 - TMAP2A (possibly serial 2)
pin 9 - TMAP2B (possibly serial 2)
pin 14 - ground
pin 15 - power


Clearly there is a difference. Which do I use?




Thanks,
Jeff

Rob Hickman
11-30-2014, 09:15 PM
You need to use the AF-5000 manual connections, page 162

1. Make sure that you connected the Transponder TXD to the EFIS RXD
2. Make sure that you connected the Transponder RXD to the EFIS TXD
3. Make sure you have power to the transponder
4. Make sure you configured the EFIS serial port for the transponder
5. Make sure you configured the EFIS Transponder menu

If all this fails give us a call from the plane.

jcaplins
12-10-2014, 09:29 AM
Update:

1st: It is a SV-261. There is a sticker on one side that I missed when I posted the original question. I had it wired correctly the first time.
2nd: Thanks to Rob and his techs for talking to me.

Long story short: I tried all possible combinations of wiring serial ports to and from the Xponder to EFIS. I connected other devices to the serial ports I was trying to use to verify they work. I used different power sources for the Xponder: 2 different power pins from VPX, different buss, and even a separate battery connected only to the Xponder. I tried new wires and pins for power, ground, and serial connections. I even bypassed the Dsub connector and pushed the pins directly into the Xponder. I sent the Xponder back to Rob and he tested it in his plane and I got the dreaded "no fault found."

After receiving the Xponder back, It was still not working for me. Basically re-did everything above without any luck.

Before dousing it with 100LL and striking a match, I connected a test lead from the case to ground and it started working. (!!?!!) Powered everything off, removed the test lead, powered back on and it was still working. (!!???!!)

I had continuity from the case to ground before. The metal tray is bolted to the aluminum structure; the structure is primed, but there is still continuity. Maybe just not enough. I don't recall reading that the case and mounting tray needed to be grounded, but apparently it does. Or is this not normal?

Rob Hickman
12-10-2014, 09:41 AM
Should work without being grounded, when I tested your unit in my RV-10 it was only plugged into the harness and not touching the airframe ground.

It almost sounds like you had an intermittent wire break or short in the wiring.

Rob Hickman
12-10-2014, 09:42 AM
If the problem happens again I will send you our test harness to try.