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Please explain data connections

M

maxmirot

Well Known Member
I am looking at two wiring diagrams. One is data connections from Advance Flights Panel. It shows connections from GPS and EFIS data.

The next diagram is from Onspeed AOA, it shows GPS and both EFIS RX and EFIS TX connected together.

Obviously, this works. I would like a better understanding of how these data sources can be connected together a still function.

Thanks
Max
 

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You can have one Tx line connected to Two Rx lines, but not the other way around. Can't tell you why they want their own Tx connected to their own Rx, but it doesn't violate the RS connectivity rules.
 
Interesting. Looks like GPS commonly mixed with EFIS data.

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Can two devices piggy back the on the same pins to share the same EFIS data?

Example my back up EFIS such as the AV-30 (back up EFIS/ADHRS LIKE THE G5) and a AOA unit? This assumes you have free ports to assign to each device and the EFIS air data format is identical .
 
maxmirot said:
Interesting. Looks like GPS commonly mixed with EFIS data.

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Can two devices piggy back the on the same pins to share the same EFIS data?

Example my back up EFIS such as the AV-30 (back up EFIS/ADHRS LIKE THE G5) and a AOA unit? This assumes you have free ports to assign to each device and the EFIS air data format is identical .
Click to expand...

No mixing going on. According to the diagram, the EFIS is sending some data on that Tx line and both the EFIS Rx port and the GPS Rx port are receiving that data at the same time. Sorry, but no logical reason why the EFIS would send data to itself via an RS-232 port. It has to posses that data in order to send it, so no logical reason to send it back to itself on a data line, except the possible reason is to look for data line errors not caught by the 232 error handling protocol (checksum), but that is very non standard practice.

Given that the diagram is not from the manufacturer, it is possible that the port labels on this diagram contain errors. I don't think I would trust a diagram that shows a device sending itself data via RS-232. Major red flag that something is not right.
 
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The OnSpeed wiring diagram doesn’t look right. For example, there is no provision to drive the Energy Display because the signal is connected to incoming RS232. If AFS provided you this wiring diagram, perhaps they should contact one of the team (me included) to discuss.

I can contact Rob Hickman if necessary.
Vern
 
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The 1st Diagram showing a GPS to EFIS connection is from Advance Flight documentation.

The second Diagram is from Onspeed's documentation. I assume this has been tested I just don't understand it either.
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Right now Advanced is closed until next week. The Onspeed AOA is recent addition. I was hoping to connect it this week.

Advance tech support suggested I get EFIS data RX TX that is present on their Back Pp EFIS connector. This connector has two RX TX connections.

There 1st one is connected to the AV-30.

They suggested I used the 2nd RX TX pins. The problems is they forget the system they built for me is already using the second RX TX on the CO detector.

I was wondering if the AV-30 data could shared in parallel using the same pins since it is the same data just need to into the AOA. Look like the same format data.

Max
 
vlittle said:
The OnSpeed wiring diagram doesn’t look right. For example, there is no provision to drive the Energy Display because the signal is connected to incoming RS232. If AFS provided you this wiring diagram, perhaps they should contact one of the team (me included) to discuss.

I can contact Rob Hickman if necessary.
Vern
Click to expand...

I am not connecting a display to Onspeed AOA.
Audio is all I want.

It is possible buy an tiny optional display if the user wants.
It is connected to the TTL pin. I am not using it to start with.
The idea is to fly by tone.
 
maxmirot said:
Do you think the EFIS TX is not used in normal operation ?
Click to expand...

Honestly I don't know. I can't find a complete wiring diagram. The "aircraft wiring diagram" only shows the minimal required.

In the setup guide it gives the option to send and receive EFIS data. The TX side seems to be for the onspeed display or for showing AOA info on a g3x. The RX side seems to be for logging? Again I'm mostly guessing here.
 
That diagram in post #1 is a test harness diagram :) We tie some serial lines together so we can test the TTL to RS232 converter chip in a loop. We built this test harness to test the hardware before we send them out to our beta testers.
Please don't use that diagram for your in-airplane wiring.

We don't use GPS data, so leave that off.

The only Efis that requires data sent to it is the AV-30 and we don't have that implemented yet. (Before receiving data from the AV-30 you need to tell it which fields you need and at what frequency, all the others just send data automatically)

You can send data to the display via pin12 (EFIS/Display RS-232TX) or Pin 9 (TTL). You will need to power the display separately, via 5V DC-DC converter, Vern's power board, or any another 5V power source.

Don't forget to set your AFS serial port to send the proper data stream. We process and log data from the ADHRS and EMS streams.

If you have any other questions email us at [email protected], we're happy to help.
 
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