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Need Garmin 430 wiring help

UH1CW2

Well Known Member
I just purchased a Uavionx AV-30 and a EDM 830 engine monitor. I would like to wire them to the Garmin 430 for the GPS tracking function. I just need to know if I can use the RS232 output pin from the P4001 connector garmin 430 unit and split the signal to both units. Or if someone has another idea please chime in. Any help in hooking these units to the 430 GPS is helpful.
 
Looks to me like there are 4 discreet RS232 channels on P4001.

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Garmin 430 RS232 Question

Ken, Do you think I can use one RS232 output and split the signal to both devices? Each is looking for GPS position information. Neither need to feed back to the 430.
 
Short answer "no". RS232 is a "push-me-pull-me" kind of circuit. You need both legs. And, each peripheral is treated as a discreet component.
 
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I know you probably aren't looking forward to it. But IMHO, you're gonna want to add 4 more wires (2 for AV30 and 2 for EDM 830) to P4001.

We routinely "add" and "delete" wires to existing bundles in the commercial aircraft world. It takes a little patience. But, its not that difficult to add 2 wires to the back of P4001, then snake them through clamps alongside the existing bundle.
 
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So I will put in 2 circuits for each device, TX and RX. What serial ports would you use in the P4001 Connector , 56 & 57 and 58 & 59? Does it matter what serial ports I use out of the 4 sets available?
 
So I will put in 2 circuits for each device, TX and RX. What serial ports would you use in the P4001 Connector , 56 & 57 and 58 & 59? Does it matter what serial ports I use out of the 4 sets available?

It doesn't really matter which ones you use as long and you use the same number tx and rx for each component (ie tx1 and rx1, tx2 and rx2...) Think of each pair as a channel.

If it were me, I'd just use 1 (pin 56 and 57) for the EDM 830 and 2 (pin 58 and 59) for the AV30.
 
I was just looking at the wiring diagram for the AV30. The one I saw had a single wire from the GPS to the AV30. And, it is calling it RS232. It uses a shielded wire with the shield grounded at both ends instead of twisted pair.

I was really sure you had to have both tx and rx connected, even though the data flow is only transmitted from the GPS. I'd still connect both wires anytime they're shown in the wiring diagram.

Is this the same wiring diagram you have for your AV30?

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Short answer "no". RS232 is a "push-me-pull-me" kind of circuit. You need both legs. And, each peripheral is treated as a discreet component.

This is bad advice. There are lots of ‘one way’ installations. For example I feed rs232 data out from my SL30 in to my grt EFIS. But I have no interest in pushing frequencies to the SL30, so there is no rs232 out from the efis in to the SL30. What you need to check is the format or formats each of these devices can ‘read’, and at what baud rates, and if the 430 can output data with that format and baud rate. If the AV-30 and edm 830 both use the same format and baud rate, then yes, you can use one rs232 out port on the 430 (set to that format and baud rate) and split the signal to both inputs. If they require different formats or baud rates then you will need to use two different output ports.
 
Short answer "no". RS232 is a "push-me-pull-me" kind of circuit. You need both legs. And, each peripheral is treated as a discreet component.

This is incorrect. You can split the Transmit line to multiple devices. They would all need to accept whatever protocol is being sent. The Receive line can only have one signal coming in. Multiple signals would collide and create garbage.

You can use the TX and RX lines on the same port to totally different devices. They do not need to stay paired to the same device. I've done it get my 430W, 796 and SL-30 to talk to each other.
 
430 TX and RX data

So, it sounds like I can split the TX from the 430 provided that each device it goes to Be on the same baud rate and format.

Spoke with Uavionx and they stated just a TX line from the 430 was required, no TX back to the 430 was needed, as the AV30 does not provide any info to the 430 GPS.

The JPI 830 seems to be a bit different requiring both TX and RX from the 430 to the JPI 830. Looks like I can split the single TX from the Garmin 430 providing both the AV-30 and the JPI 830 require same baud rate and format. Just one line back to the 430 from the JPI 830 EDM.

**** at tis point I might as well just plumb the Garmin 430 with 4 circuits, TX and RX form 2 channels.

If some has a better solution I am open to all comments and suggestions.
 
This is from dim memory of wiring my 430/GRT/Navworks/Digitrac and stuff together 10 years ago.

There was some restriction I ran into on the 430 that caused some headache.

I *think* it was inability to assign the same data format to two different RS232 TX ports.

I wound up splitting a 430 TX output to go to 2 different devices. I had wanted discrete wires, but no. Of course it was after power up that I learned of the issue and had to tear back into the harness.
 
“I *think* it was inability to assign the same data format to two different RS232 TX ports.”

You are right. I had the same issue - had to split the feed to the D180 and G5 because both required the same format. It works perfectly, although my avionics guy didn’t think it should!

Jack
 
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