encoder connection with approach systems harness

[billnaz]

Any ideas on trouble shooting D100 to Apollo SL70 xpndr communication via my Approach systems harness and Pro G Fast stack hub? I've already selected potocol 1 on D100, and selected 1200 bauds on the SL70. Still no alt indication on the SL70. Any way to verify my D100 is outputing a signal which 'aint getting through?

P.S. -My D100 is in the panel and looks great! Hoping to fly my RV6A in the spring.

 

[dynonsupport]

Re: encoder connection with approach systems harne

I'm not familiar with either the harness or hub that you have, but you should be able to test the serial out by connecting the appropriate wires from the EFIS it to a 9 pin D-sub connector. Then hook it up to a PC serial port and use a program that can connect to it (such as Hyperterminal - included with Windows). You can then see the data being outputted by the EFIS.

The connections you would need to make:

EFIS Pin 9 pin D-sub connector pin
21(xpdr TX) 5
13 (gnd) 2

Also, in general, check that the format that the EFIS is outputting what the Apollo is expecting to receive. Some manufacturers' units can be set to receive different formats.

 

[billnaz(Guest)]

Re: encoder connection with approach systems harne

Problem was in the Approach Systems harness. Thanks for your help!

FYI- the tech at Approach was quick to track down their error and walk me through a fix. I'm pretty happy with their product. I'ts a good compliment to the D100 in simplifying installation for the ham fisted.

 

[drpohl]

Re: encoder connection with approach systems harne

Hello:

I have a similar setup as yours (D10A and SL70) and my problem is that the Pressure Altitude readout on the transponder is present, then without warning, goes to flashing bars. This happens wether I am flying or on the ground with the engine off and sitting perfectly still. The PA reading comes back when I either cycle the D10A off and on, or cycle the transponder off, then on.

How did you determine the Approach System cable was the problem? I had my SL70 Bench Tested. The avionics repair station said the SL70 was fine and the reason the PA goes to flashing bars is because the encoder is loosing a line (or two) of code. Dynon says it is the transponder.

Thank you in advance.

Dave

 

[dynonsupport]

Re: encoder connection with approach systems harne

Just to clarify - the reason is sounds like a problem on the transponder end is that cycling the transponder fixes the problem. Also, if there were something wrong with the EFIS, you'd have to rebook it to fix the problem. The fact that rebooting the transponder (but leaving the EFIS powered on) fixes the problem implies that there is a good signal coming from the EFIS. Even if a "dirty" altitude sentence was broadcasted, the transponder should ignore it and pick the data stream back up as soon as it gets good data again.

All that said, if you don't have a ground going directly between the EFIS and transponder, try hooking one up. That may help dissipate any noise that could theoretially (but not likely) affect the serial connection between the two.

 

[drpohl]

Re: encoder connection with approach systems harne

How would I "hook up a ground going directly between the EFIS and transponder" as quoted below?

"All that said, if you don't have a ground going directly between the EFIS and transponder, try hooking one up. That may help dissipate any noise that could theoretially (but not likely) affect the serial connection between the two. " ??

Also, could I determine if the Approach Systems Cable is or is not providing the serial signal by attaching an ammeter on Pin #13 on the cable for the DYNON and on Pin#4 on the cable for the SL70 Transponder?

Thanks

Dave P

 

[dynonsupport]

Re: encoder connection with approach systems harne

Pin 21 on the EFIS harness is a ground. Just connect it to ground on the transponder.

For checking the Approach cable, you can check for continuity between our connector's pin 13 and the approach cable. Beyond that, you'll need to go directly to them for support on their products.