Been messing around for last 3 hours trying to get decent focusmax curves
Started off well with a series of 4 curves with a PID of around 2 - 3.2
Tried to get things better and thatswhen things went south
Curves looked good but PID was all over the place.
I also noticed the absolute focus position seemed to be changing every run
At first I thought the focuser must be slipping. Tightened the coupling to robofocus.
Same result. Changing absolute focus point.
Then I thought I may have overdone backlash compensation so I decided to use some digital vernier calibers on focuser to check what was going on
So next i tried following sequence
1. Measure distance
2. Tell focuser to move out 200 steps
3. Tell focuser to move in 200 steps
4. Measure distance
The distance was .5mm different
This got worse further out I moved focuser.
Played with backlash comp but no difference.
Rebooted everything. reset robo. Same result.
Decided to recalibrate the travel points and noticed the motor was buzzing and not moving scope in. I then remembered I read something a while back and changed duty cycle from 50 down to 5.
Eventualy I changed the duty cycle on the motor to 50%
Bingo. Travel recalibrated straight away.
Started re running curves and am now getting 1 - 2.5 PID's as I type this...
!@$%#&* Some nights things just dont go your way.
At least I sorted it in the end I guess and this may be of use to someone one day who sees same behaviour