Selecting OBS source to NAV from independent CDI (EFIS)?

The instrument panel for the RV-7A I'm building will have an Advanced Deck 4500s, a GNS430W, and a SL-30. It will use a Dynon D100/HS34 for backup. Both the 4500s and the D100/HS34 can be used for CDI (Course Deviation Indicator). I would like to have both the 4500s and the D100/HS34 RECEIVE information from the GNS430W and the SL-30 and I would like to be able to SELECT which CDI provides the OBS information to each NAV unit.

Is it possible to be able to select either the 4500s or the D100/HS34 to provide the OBS information to the 430W and/or the SL-30 while both the 4500s and the D100/HS34 display the CDI info? If so, how would this be connected?

Regards,

Roy

Hello Roy, you could certainly do that with a bank of relays or a switch with many poles. That goes far beyond our wiring diagrams. I'd recommend contacting your local avionics shop for help with the wiring or drawing up a schematic for you.

Trevor, Thanks, A few more details would be helpful.

(Should this have been posted to the "EFIS Installation Questions" forum?)

Selecting the OBS input to the SL-30 looks fairly simple:
I understand that the serial communication TO the SL-30 from the 4500s contains the OBS information. The serial information FROM the SL-30 to the 4500s can be shared with another CDI (HS34/D100 for me). Therefore it seems like a SPDT switch could be used to select which CDI/OBS communicates to the SL-30. Correct?

Selecting the OBS input to the GNS430W looks a bit more complex: I don't understand the details of the communication between the 4500 and the GNS430W. The ARINC -429 adapter cable schematic (http://www.advanced-flight-systems.c...%20Adaptor.pdf) shows the 430W connected to

4500s Serial #1 TXD to 430 GPS RS232 IN 1
4500s Serial #1 RDX to 430 GPS RS232 OUT 1

ARINC adapter ARINC In 1-B (VOR/ILS) to 430 VOR/ILS ARINC 429 OUT B
ARINC adapter ARINC In 1-A (VOR/ILS) to 430 VOR/ILS ARINC 429 OUT A
ARINC adapter ARINC In 2-B (GPS WAAS) to 430 GPS ARINC 429 OUT 1 B
ARINC adapter ARINC In 2-A (GPS WAAS) to 430 GPS ARINC 429 OUT 1 A
ARINC adapter ARINC Out B (OBS & AP) to 430 GPS ARINC 429 IN 1 B
ARINC adapter ARINC Out A (OBS & AP) to 430 GPS ARINC 429 IN 1 A

Surprising that 430 "VOR/ILS ARINC 429 IN B" and "VOR/ILS ARINC 429 IN A" are not used.

From the above connections, it looks like ARINC adapter ARINC Out B (OBS & AP) and ARINC adapter ARINC Out A (OBS & AP) communicate the CDI/OBS information to the GNS430W. Is this correct? Then the ARINC Out A (OBS & AP) and ARINC Out B (OBS & AP) signals could be selected with a DPDT switch to select which CDI/OBS communicates to the GNS430W. Correct?

I'm also realizing that the setup for the GNS430W communication from each CDI/OBS would need to be the same and the 4500s may not use the same setup as the HS34/D100!

Regards,

Roy

Hi Roy,

Your last comment may be the largest problem. I'm not sure what format or speed Dynon uses for ARINC and Serial vs ours. It may be more than just a toggle switch that needs to be thrown in that case.

SL-30 - You can't just use the TX and not the RX or visa versa. You will need to switch both TX/RX from each unit to the SL-30. A 3 pole switch could be used pretty easily to do this.

GNS-430 - This is a bit more complicated since ARINC has both an A and B wires. You will need to switch both GPS ARINC wires and the VOR/ILS ARINC wires. So that would be a 4 pole switch.

The easiest thing would probably be to use a bank of 3 DPDT relays so one toggle switch could be used to control the entire switching assembly.

As a correction to my previous post.

The SL-30 TX line can be split to multiple devices, however the RX needs to be switched between sources.

The GNS-430W/530W ARINC outputs can be split between multiple devices, however the RX needs to be switched between sources.