Garmin GTX 327 question

[jthocker]

Maybe Stein can answer this.
My 327 transponder is getting RS232 Data from both my Dynon D180(ch 1) for the encoder, and from my 496 (ch 2) for groundspeed.
The encoder works like a champ. The unit goes from standby to ALT automaticly but does not "appear" to go into standby on the ground after the default 24 seconds of zero groundspeed.

Ch 1 is set to Icarus Alt
Ch 2 is set to GPS
Autostandby is ON
Squat swiches OFF

Am I missing something.

[mburch]

I may be wrong, but I don't think the GTX 327 knows how to listen to the NMEA data format that's spit out by the 496.

mcb

[jthocker]

Matt
I don't know which part of the stream it might use but it does use GPS groundspeed to auto turn on/off.

[Brantel]

Go to the serial data viewing page (3.3.8 page 31 in the install manual) and see if your recieving the GPS data, if not, I suspect the wrong format or baud rate being output by the GPS or a wiring error.

[jthocker]

Thanks for the suggestions guys, but the wiring is correct and the baud and format is correct(Aviation and VHF) on the 496. SL40 loads frequencies from the 496, Dynon gets gps data from 496, and 327 goes from stby to Alt via gps data from 496. ALL OF THIS STUFF IS WORKING CORRECTLY!!
After shutdown at the hangar the transponder still says "ALT".
I'm wondering if there is a bug in the transponder software and it needs to be updated.

[Ironflight]

Mine has always done the same thing Jon - it automatically goes to "ALT" when I launch, but I have to manually take it to STBY afer taxiing clear of the runway. It's on my checklist, and part of my routine cockpit sweep, so I have never gotten up the gumption to figure out if I can make it do it by itself....

Paul

[jthocker]

Thanks Paul
Stein, any answers?

[Ted RV8]

Mine does the same thing. It is wired and programed correctly. I do like Paul does and manually go to STBY after landing. Always goes to ALT automatically when I take off.

Be interesting to see if there is a fix. The book says it's supposed too.

Ted

[w1curtis]

Make sure you have the wiring correct per the drawing in this thread. Then make sure you are outputting "Aviation Data" to pin #2. Then make sure the unit is configured correctly. Newer units are able to transition to ALT using the change in pressure altitude so if they are not getting Aviation Data and cannot see the speed transition, they can toggle to ALT but will not toggle back to STBY.

[SteinAir]

Hi John,

I don't acutally have any better answers for you than anyone else. Mines running off of a 430 so I don't have a good comparision. Let me do some quick homework and see.

Cheers,
Stein