Problem with servo settings


I want to setup my swash plate servos, but oddly it’s not possible to save the MIN/MAX values for the servos 1 to 3. At every restart of the APM the values HSx_MIN and HSx_MAX are set to the defaults (1000 and 2000). Only the trim (HSx_TRIM) remains its value.

Is that a known issue? How do I tune (and level) my swash plate then.

My hardware: HK-450TT PRO V2 Flybarless + APM 2.5 (Firmware 3.1.5)

All the best, Markus

Cross-posted from DIYD:

Yes, this is a known issue. It’s been this way forever.

Basically, the system was not set up to remember the Min and Max values for each individual servo. I’m not sure why, this goes way back.

The way you do this is using the Trim value to center the servos. Collective Min and Max to set the collective travel. And then you’ll also see Roll Max and Pitch Max. Those limit the maximum Roll and Pitch movements. You should be able to get it working using these. Typically a Roll Max and Pitch Max of 25 degrees is appropriate for most flybarless setup. If you have a weird machine which still binds when doing this, then I’m not sure what the short-term solution is.