OAT, Serial-Parallel encoder, EFIS data log file

[canardflyer(Guest)]

OAT:

Thanks for the prompt delivery of the replacement OAT probe. I received it on Friday as expected.
Replaced the old probe with the new one and the OAT value showed up on the display. Thanks!

Serial-Parallel Encoder Module:
I have a Narco AT150 gray code (parallel) xponder. Ever since I upgraded the D10 to D10A with the serial to parallel encoder coverter, I don't seem to get altitude encoding. Few weeks ago I did an inflight xponder check with the local approach control with negative results. Recently, I took out the AT150 and checked the wiring and connector and even replaced a suspect connector pin. Today I did another in-flight check with still no altitude encoding on my signal. Is there an easy way to check the encoder converter module? Any help on this matter will be greatly appreciated (considering that I fly out of an airport which is very close to the mode-c 30nm zone around LAX).

EFIS Data Log File:
I also logged a couple of minutes worth of data on the ground with engine off to check out the serial interface. Moved the airplane in yaw a bit and varied the baro-pressure. It all registered in the data stream as expected.

I parsed the data stream to plot it and noticed that the second count increment has a consistent five step (1/64th second step) lag at the end. It showed up as non-causal data points when I tried plotting the data against time. Below is an excerpt of the data file, with the affected second and frac. of second lines underlined. Note the second field takes five extra sample before it increments.

12224160+002+00013380000+0041+001-00+1099002BF60181
12224161+002+00013380000+0041+001-00+1099002BF60182
12224162+002+00013380000+0041+001-00+1099002BF60183
12224163+002+00013380000+0041+001-00+1099002BF60184
12224100+002+00013380000+0041+001-00+1099002BF6017B
12224101+002+00013380000+0041+001-00+1099002BF6017C
12224102+002+00013380000+0041+001-00+1099002BF6017D
12224103+002+00013380000+0041+001-01+1099002BF6017F
12224104+002+00013380000+0041+001-01+1099002BF60180 *
12224205+002+00013380000+0041+001-01+1099002BF60182
12224206+002+00013380000+0041+001-01+1099002BF60183
12224207+002+00013380000+0041+001-01+1099002BF60184

 

[dynonsupport]

Re: OAT, Serial-Parallel encoder, EFIS data log fi

Regarding the altitude encoder function and encoder converter, please verify that your EFIS-D10A is outputting the correct data format. There are four formats, and you must have it set to format #1 to work correctly with the serial-to-parallel converter. If you are using format #1 and you still have problems, here are a couple simple tests you can do on the converter and your transponder:

You can test the output of your encoder converter against your known altitude using a voltmeter, wiring diagram, and a table like this one: http://www.airsport-corp.com/modecascii.txt. Just verify that the proper wires are set to zero (ground) for the current altitude. If they are not, then either the EFIS is not outputting the altitude correctly, or the converter is not converting the altitude correctly.

You can test your transponder in a similar way. Ground various input pins on the transponder, and verify that it outputs the correct altitude (use the same table linked to above).


Regarding the data logging seconds transitions not lining up with the time fractions, we are aware of the problem. We know why it happens, but we consider it a low priority problem for now. That's not to say we won't fix it someday, but just not right away.

 

[canardflyer(Guest)]

Re: OAT, Serial-Parallel encoder, EFIS data log fi

Thanks for the quick response as always...

I appreciate the alt. to gray code conversion table. That will come in handy to check the encoder converter module output while it is hooked up with the EFIS, with the input being varied using the baro adjustment on the EFIS.

I was not sure how I can check the transponder output by grounding the various pins. Doesn't it radiates its encoded altitude which is not readily accessible for ground testing, without an avionics testbench?

I am not surprised that you folks are already aware of the sub-second time warp. It is really not critical, just thought I mention it.

Thanks as always...

 

[dynonsupport]

Re: OAT, Serial-Parallel encoder, EFIS data log fi

What we mean to say is that you can measure the output of the serial converter by checking the output of each wire with an ohmmeter. Using the table given, you can set the EFIS to 29.92 and then check the output and make sure the right wires are grounded. The wires will read open when they are a "0" and grounded when they are a "1". You can go into the alt adjust in the setup menu in the EFIS and adjust this altitude up or down 500 feet and see the change. Remeber to put the alt ajust back to the factory setting when done, and also remember that grey code only reports 100 ft altitude changes.

You can do the reverse at the transponder- ground a wire and it should transmit what the table says that altitude is. This works better when your transponder has a display for altitude instead of just transmitting random altitudes!

 

[canardflyer(Guest)]

Re: OAT, Serial-Parallel encoder, EFIS data log fi

Just a note to let you the latest status.

The replacement OAT probe that you folks sent ealier has been installed and working great.

This weekend I also found out that I had goofed on the wiring of the serial to parallel alt encoder installation. After the wiring fix, all is well as confirmed by the local approach control getting the encoded altitude.

Thanks for the great customer support!