Erratic NMEA stream to Trio ProPilot and Dynon

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HomeHomeDiscussionsDiscussionsiFly General Di...iFly General Di...Erratic NMEA stream to Trio ProPilot and DynonErratic NMEA stream to Trio ProPilot and Dynon
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1/15/2018 5:27 PM
 

I have been Flying Trio products since before they were released (beta tester) and was also an early adopter of the Dynon D-10A. I sent NMEA to those devices with a Lowrance 1000 and then an iFly 700 with very reliable service. After upgrading to an iFly 720 I am seeing fairly frequent failure of the NMEA data to the Trio and Dynon. Most of the time it returns after being down for a few seconds but occasionally the 720 has to undergo a hard reboot to get NMEA streaming again. Since both devices are losing data at the same time the failure must reside somewhere in the 720 architecture. My hangarmate with an iFly740 and Trio autopilot has seen the same issue.

The 720 maintains GPS lock and full funtionality during the loss of NMEA stream and NMEA config is for extended mode with recommended parameters.

Thanks in advance for troubleshooting or resolution ideas.

Sam Buchanan

 

 

 
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1/22/2018 10:37 AM
 

Sam,

My gut feeling is that your cable could be failing..

How long have you had your USB to Serial cable?

-JJ

 
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1/22/2018 8:25 PM
 

I just flew from South Florida to Texas on Friday. About halfway, my Trio indicated "no gps". So I tried cycling the Trio, no luck. Had to hand fly for awhile, but decided to troubleshoot enroute. I went to iFly Settings, and found that nmea output was "off". Restarted nmea and the Trio came back to life. It kept repeating this about every 15 minutes, but all I had to do then was go to the nmea page and the Trio would restart. This is with a 740. I've never seen this before. Just updated with the latest beta software the night before. Possible correlation?

 
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1/23/2018 10:03 AM
 
Sam Buchanan wrote:

I have been Flying Trio products since before they were released (beta tester) and was also an early adopter of the Dynon D-10A. I sent NMEA to those devices with a Lowrance 1000 and then an iFly 700 with very reliable service. After upgrading to an iFly 720 I am seeing fairly frequent failure of the NMEA data to the Trio and Dynon. Most of the time it returns after being down for a few seconds but occasionally the 720 has to undergo a hard reboot to get NMEA streaming again. Since both devices are losing data at the same time the failure must reside somewhere in the 720 architecture. My hangarmate with an iFly740 and Trio autopilot has seen the same issue.

The 720 maintains GPS lock and full funtionality during the loss of NMEA stream and NMEA config is for extended mode with recommended parameters.

Thanks in advance for troubleshooting or resolution ideas.

Sam Buchanan



Sam -

I experienced a problem very similar to what you describe. It did in fact turn out to be a faulty USB-to-serial cable connecting my iFly. Symptoms include a loss of NMEA data from my 740 to my Dynon D-100, Tru-Track Auto Pilot and FC-10 Fuel Computer. The aggravating part was it was an intermittent - the 3 devices mentioned would indicate a loss of NMEA data and then after some time, the data would return. The loss of data time interval was totally haphazard and random. I too am an iFly Beta Tester and thinking it was a faulty GPS after a beta software upgrade, I spent a lot of time talking to the iFly techs and testing. We finally decided replacing the data cable was the next logical step in troubleshooting. After I did this, I have never had another failure. Examining the faulty cable I found I had inadvertently nicked/partially cut the cable with wire cutters when I was cutting a tie-wrap holding the wire bundle.

Maybe it's worth a try replacing your serial cable? Also, talk to tech support. Maybe they can help with some desktop software that can read and display the NMEA data in real-time?

Andre'
 
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1/23/2018 2:26 PM
 

Greg,

It could be a faulty cable, as Andre' noted.  Or it could be noise in your electrical system - either from other equipment on board, or by a ground-loop (since the iFly and the Autopilot are (probably) grounded differently - a voltage difference could exist, and this will try to "even out" through the autopilot cable connecting the two systems.  In an audio system, this causes the humming noise we're all familiar with.  In a digital system like this, it's not a problem unless it gets bad enough to cause signal loss.). 

Long story short, I would check your power connections to both systems.  And if you had any other new equipment or something else that might put out RF noise during that flight, try again with that off.  And to Andre's point, it might be your cable is going bad.

-Walter    

 


Walter Boyd
President, Adventure Pilot
 
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