View Full Version : Gain or setting for AP and IAS climb

04-22-2016, 12:50 PM
I updated to the latest release on my 5600T and have appreciated the new IAS climb option for the AP. However when I engage the AP with this mode and I am already at the desired IAS, the AP commands a slight nose down until it is about 10knots over the set IAS setting. It then pitches back up and resumes the IAS that was set. This takes about 2-3 minutes. Is this by design? Is there a Gain setting that should be tweaked for this? A better configuration to be in before engaging the AP? This is for an RV10.

Shawn McGinnis
04-25-2016, 12:23 PM
You can tune the IAS mode with the ASPGAIN, ASIGAIN, and ASDGAIN. Basically AirSpeed P-I-D GAIN.

I would probably start in your case by adjusting the ASIGAIN because it sounds like its becoming stable but not correcting for the offset.

04-25-2016, 12:29 PM
Thanks Shawn. It does maintain the set IAS, but seems like initially it wants to be over the set IAS and then nose up until it reaches the set IAS climb speed and then maintains it.

Shawn McGinnis
04-25-2016, 02:10 PM
Right that's why I think the error window is too large. There is a bunch of PID tuning tutorials online that can be helpful. It's a bit of an art.

04-25-2016, 04:01 PM
Shawn, about that link to the PID tuning tutorials?

Shawn McGinnis
04-26-2016, 10:50 AM
Here are some fairly good tutorials




04-26-2016, 03:31 PM
That will teach me....not exactly an old fighter pilot's cup of tea. Guess I'll just keep to my present plan; tweak, observe, tweak, observe....

Fly More
04-26-2016, 04:36 PM
Try this one: https://www.youtube.com/watch?v=LtocGBngSrA

It's about PID tuning for a quadcopter but covers the details of P, I, and D very succinctly.

Shawn, where can we find these gains in the EFIS? I checked the install and pilot manuals and couldn't find a reference.


Shawn McGinnis
05-02-2016, 09:46 AM
External autopilot users will find the settings under:


06-14-2016, 02:55 AM
Coming back to this. My ASIGain was set to the default of .05. Would I increase or decrease this value to correct for the Airspeed climb problem?