Connecting (3) HX to GNS430W

[sfields]

I am trying to wire my (3) HX panel to a GNS430W using the ARINC ports. GRT has sample wiring diagrams showing a single HX to 430 connection using ARINC 429 I/O but not for multiple HX systems. I can tee off all of the ARINC HX input to connect all the units but what do I do with the HX ARINC outputs. There is only one GNS430W ARINC input pair for the HX output pair. That leaves the other two HX unit's ARINC outputs with nowhere to go?

Any ideas?
sfields

[Bobturner]

The answer to your last question is basically "yes". The 430 has only one ARINC input. Its primary function is to ship OBS data from the EFIS to the 430. You only need to wire up one HX, the other two units can send OBS data via the interdisplay link. Same is true of GPS data from the 430 into the EFIS you only need one ARINC connection and from there it goes over the interlink. If you splice the 430 output into all three, you have some redundancy in case of a single EFIS failure. To gain that same redundancy for the OBS data, you would have to run all 3 HX ARINC-out signals thru a double pole, triple throw switch, then on to the 430. Then if one EFIS failed you could select another for sending the data to the 430. Frankly, since this is hardly critical, most people do not bother. GRT recommends (see the dual display wiring diagrams on the web site) getting back up to the data from the 430 to the efis by using ARINC on one HX, and the CDI outputs to analog HX inputs on a different HX.

[sfields]

Thanks Bob. That's what I'll do.

Stan