Dynon rx and tx with vp-x

[southtarnation]

Originally Posted by Vertical Power

Great news, Jesse! We received your VP-X Sport this morning and immediately hooked it up to our Dynon SkyView on our test bench. Without any changes to the configuration of your VP-X, the box worked flawlessly. The serial communications between your VP-X and our SkyView are working fine. We'll ship your unchanged unit back to you today.

So again, when you get your unit back from us, you should be looking for the source of the problem in your wiring. I recommend you try to simplify the topology as much as possible, and get that working first, before gradually approaching whatever complex topology you require. Specifically, try connecting just a single SkyView screen and your VP-X on your test bench. Use the recommended gauge wires, and double and triple check that you are using the correct pins (pin misidentification is the number one problem I've seen customers have).

We'll continue to be happy to help you track down this problem. Let us know what we can do to help.

Best wishes,

Stephen

What are the minimum components I should start with?
My "system" only uses one screen.
I believe that the engine/ems module has to be hooked up, all wires (power, grounds and serials) between the vpx and sv7. And power and ground to the vpx unit. Are there any other minimum operation components or wiring that should be installed to troubleshoot the vpx to dynon comm issue?

Can you point me to a diagram of the physical ports on the harnesses?

Regards,
Jesse

[SteinAir]

I know you've said you checked your wiring, but like most things with these newer boxes, almost 99% of install issues are user induced....so that's where to start (which you did, but didn't find any issues). Are you absolutely 100% certain that you didn't accidentally hook a "Tx" to a "Tx" and an "Rx" to an "Rx"? This is a very, very common error with folks hooking up serial ports and the like. If Vertical Power tested your boxes with no issues, then that leaves the most likely problem to begin with....your wiring (on one end or the other, or in between, or with crimps, etc.). Simply ringing pin to pin for individual continuity won't necessarily give you the answer if you happen to have one pin touching another in the connector, a pin touching ground, or if you verified an induced error that you don't know you've made. Also, are there any splices/joints in between your harness, and again, are you certain you have the right wires going to the right place? It also is possible there is a configuration or other issue with your Skyview, though it's less probable than a wiring problem.

I don't know the answer, but I do know it's just a matter of taking it one wire at a time and fining out what is going on. Perhaps just whip up a new and quick jumper harness to test (like what VP used or what we use) to see?

Sorry I don't have a good answer, but the answer has to lie there somewhere.

Cheers,
Stein

[Bill.Peyton]

Jesse,
It seems you have spent an inordinate amount of time with this issue. I would suggest that you consider having someone fabricate an entire harness for your application. In the long run, you may find that it costs less than the possibility on damaging your expensive avionics. Possibly a local avionics shop. I would create a drawing of your requirements and get a quote.
Setting the above aside, Stein offers a lot of good ideas. You know the equipment works properly, so it must be a wiring error. Start one wire at a time....
Bill

[southtarnation]

Thanks for the additional input guys. I rolled my fuse this weekend in prep for painting the bottom so I wast able to do a lot of troubleshooting while I was there this time but will be troubleshooting each wire next weekend. Ill also try to simplyfy the system and do a bench test too.

Stein, I have triple checked that tx is to Rx. I do have a splice in serial set 1, so I added connectors directly to the sv harness for serial set 2 and substituted serial set 2 for 1 in the vpx harness and made all the necessary software changes in the dynon set up with the exact same results. Incrementing on the tx to the vpx but 0 on the Rx from the vpx. Based on that test it's isn't the serial wires or splices as they all loop back fine. I have triple checked the ports and got another set of eyes to verify. The info connection seems to be failing after the tx enters the vpx harness as no return info is received back out. I did all of my loop back tests on the serial lines by removing them from the vpx harness and holding the pins together. I think then that the puns are installed correctly to the wires. Should I loop back test serial lines while they are still in the vpx harness?

By process of elimination I think that the issue is with my ground. Will a bad ground (grounding block not well grounded) cause the issue of tx incrmenting but not Rx? While leaving everything else apparently grounded well enough to operate? (Like the sv screen)

Thanks again!

[az_gila]

Originally Posted by southtarnation

.....

By process of elimination I think that the issue is with my ground. Will a bad ground (grounding block not well grounded) cause the issue of tx incrmenting but not Rx? While leaving everything else apparently grounded well enough to operate? (Like the sv screen)

Thanks again!

Try a short temporary jumper cable tying the cases of the two devices together as a quick test of your grounding....

[southtarnation]

Originally Posted by az_gila

Try a short temporary jumper cable tying the cases of the two devices together as a quick test of your grounding....

Ok, will do. Thanks

[dynonsupport]

The idea of a basic harness is a good one.

SkyView will boot and operate with just power and ground connected. If you build a D37 with power, ground, serial X TX and serial X RX, then you only have 4 wires to worry about.

Then hook the TX and RX to the VP-X, and if it doesn't work, reverse them. There is no chance of electrical damage from reversing TX and RX.

If that works, then you can go back to your main harness and see what is different.

[southtarnation]

Originally Posted by dynonsupport

The idea of a basic harness is a good one.

SkyView will boot and operate with just power and ground connected. If you build a D37 with power, ground, serial X TX and serial X RX, then you only have 4 wires to worry about.

Then hook the TX and RX to the VP-X, and if it doesn't work, reverse them. There is no chance of electrical damage from reversing TX and RX.

If that works, then you can go back to your main harness and see what is different.

This is exactly what I'm gonna do. Thanks for the confirmation. I will be able to see both the Rx and tx lines incrementing from the setup page. So no need to plug in the ems module until after that has been verified? I'm pretty sure that to see the "vpx page" on the dynon display I'll need the ems connected?

[dynonsupport]

True, you will need to have the EMS module plugged in, but since this goes to a separate connector, it won't get in the way. I can't imagine any way anything on the SkyNet network would be causing you issues.

[rvator51]

Hi Jesse,
This is a long shot but did you see the note 1 on the VP wiring diagram? It says:
"Serial must be wired to same EFIS that is powered by J12-9'

Did you power the Skyview from J12-9 on the VPX? If not, maybe that could be causing the problem.