Wiring Question

Brambo · #1 11-23-2007, 04:16 PM

I?m currently in the process of wiring my GRT EFIS and Garmin SL-30. The GRT instructions show how to connect the Serial In and Serial Out from the Garmin to the EFIS (So far, so good). But the shielded cable coming from the Garmin has three wires. They are labeled RxD1, TxD1, and Ser Gnd. I?m assuming the Rx and Tx are Serial Out and In respectively, but where does the Ser Gnd wire go. Also, the shield is connected to the radio chassis on one end so should the shield be connected to anything on the other end?

Bill Rambo
RV-7A

Jeff R · #2 11-23-2007, 06:16 PM

The Ser Gnd is the serial ground and should be grounded. This ties the ground of the computer to the ground of the aircraft. Tie the shield only at one end -- you don't want it carrying any current.

Ironflight · #3 11-23-2007, 08:55 PM

I agree with Jeff - I have all of the serial data lines between all of my boxes (and it's a bunch!) tied to a common point, and that is tied to to airframe ground. Works great - have not had a single problem in a couple years and a lot of hours!

Paul

Brambo · #4 11-24-2007, 10:14 AM

Thanks for the info.

Bill Rambo
RV-7A