GPS 496 Output Settings

[Craig23]

Hello,

I have an AF-3500 EFIS, Garmin 496, and am planning to use a Digiflight II autopilot in my RV-8 project. The Digiflight manual says to set the Garmin to fast output, but the AF-3500 manual says it needs to have the Garmin set to normal. Is there a way to make the 496 communicate properly with both the autopilot and the EFIS?:confused:

Also, if I'm going to hook the autopilot up to a serial port on the EFIS, should that connection be made the the auxiliary RS-232 input on the Digiflight harness?

Thanks for any help.

[TrutrakTech]

Hi Craig,

The serial input to the Digiflight II has to be connected to the primary serial input pin 17.

You can use the 496 set in normal mode, but you may get a little bit of wandering depending on what mode you're using. If using the AP in track mode, it may wander a little bit. If you are flying it from your EFIS (assuming you have the G, VSG, or VSGV model) then everything should be fine.

The normal mode on the 496 sends an update to the AP once every two seconds while the fast mode sends an update once every second.

[Craig23]

Thanks Lucas,

Would I need to put a switch to select whether the autopilot input is coming from the GPS or the EFIS? I hadn't planned on using the G and the ARINC module since I'll be doing VFR flying and I wanted to save some money. Would the GPSS feature make the autopilot significantly smoother? I know I would need GPSS to anticipate turns.

Take Care,

Craig

[TrutrakTech]

Putting in a switch will be up to you, it is not required. You will probably see better performance from a model with GPSS operating from the EFIS system.