Skyview/Garmin GTX327 Issue

[alibi7]

There is lots of history on this issue. Have been working a long time to solve it. I want my GTX327 to start-up in Stby mode, then transition to Alt mode on T/O. On LDG to transition from ALT to Stby. SV Serial Port 1 RX is connected to pin20 on the GTX RS-232. SV Serial Port 1 TX is connected to pin 19 GTX RS-232. SV Serial Port 2 TX is connected to pin 2 GTX RS-232. On my Garmin327 Input is set to ICARUS ALT. Output is set to REMOTE. SQUAT SW - NO. SENSE - LOW. AUTO-STBY - ON. DELAY TIME 23 secs. Dynon settings: Port 1 Serial in Device - Garmin GTX327. Serial Out - ICARUS ALT 100ft. Port 2 Setup: Serial in Device - None. Serial Out Device - ICARUS ALT 100ft. I have tried all settings and combinations to no avail. I "think" the SV GPS is not comunicating data to the Garmin 327 or vise versa. Right now on start-up i get ALT and it stays in ALT until i shutdwn. Very frustrating, because my fellow pilots who are running a GRT EFIS are seeing STBY and ALT. Garmin firmware 10.1 Any info, to shed a light on this issue would be much appreciated.

 

[preid]

You need a switch that opens when there is enough pitot pressure, this can not be done electronically.
the 327 does not accept a standard NMEA, other than from Garmin.
http://www.vansairforce.com/community/showthread.php?t=15795&highlight=gtx+327+ALT&page=2

if it does, I never got it to work with my latest firmware. Use the switch and at 40kts or so it goes to ALT.

 

[alibi7]

Thanks for the info. It's to bad Dynon doesn't have a fix for this, being a very progressive company. One would think it would be a simple software change to get good GPS data over to my GTX327.

 

[vlittle]

I've worked this offline with the 'dog and educated him on how the 327 works (or doesn't). It needs a Garmin Certified GPS before it will switch back to STBY mode on the ground. Switching from STBY to ALT is easy because it detects a rapid change in altitude on the serial altitude data.

Unfortunately it can't switch from ALT to STBY because it can't distinguish between level flight and ground operation.

I found this out about 8 years ago. I just forgot to tell anybody.

 

[alibi7]

Thanks Vern, didn't realize GRT EFIS GPS was certified.

 

[dynonsupport]

The GRT GPS is not certified, but it outputs a serial stream that emulates a certified GPS.

This is a new request for us. The reason we don't do it isn't because we haven't tried, it's because there has been no customer demand for it. We can add it to the list, and bump it up if there is enough interest.

 

[alibi7]

Fantastic. All those many other guys forgot to request it. They all owe me. Thanks Dynon

 

[mmarien]

It needs a Garmin Certified GPS before it will switch back to STBY mode on the ground.  Switching from STBY to ALT is easy because it detects a rapid change in altitude on the serial altitude data.

Is it rapid changes in altitude or does it pick out airspeed from the NMEA stream? My GTX327 didn't switch to ALT until I upgraded to firmware 2.1. I have the second serial port RX of the GTX327 connected to my GPS495 TX which outputs NMEA and VHF data.

From the GTX327 Manual:

Also under "3.3.7 AIRCRAFT TYPE"

There is no discussion of rapid changes to altitude, just "time to STBY, required airspeed, ground speed".

 

[alibi7]

Thanks Murray, unfortunately i don't have a 2nd GPS to connect to the second serial port. The only GPS i have is the SV which isn't putting out the correct data to the GTX327 for speed.

 

[dynonsupport]

Oh, one other note in this topic. In the USA, the FAA now wants your transponder ON at all times, so you really aren't supposed to use auto air-gnd in the 327 anymore, since GND mode is OFF.

Mode-S transponders which actually have a GND mode are supposed to be in GND.

AIM 4-1-20:

3.[ch8194]Civil and military transponders should be turned to the “on" or normal altitude reporting position prior to moving on the airport surface to ensure the aircraft is visible to ATC surveillance systems.

7.[ch8194]Aircraft equipped with ADS-B (1090 ES or UAT) must operate the equipment in the transmit mode (on position) at all times while on any airport surface.

 

[XRR]

How do I feed ALTITUDE INFO from the skyview to a Garmin GTX 327 Transponder? From which pin? I suppose I don´t need any encoder, right?

 

[dynonsupport]

Page 4-16 of the install manual. You can use any free serial port on SkyView.