Hello!

I have spent some time with the machine and have tried some of the suggestions.

2012/1/27 andy pugh <bodge...@gmail.com>:
>
> At that speed with a 2-pole motor a 1ms servo period ought to be OK,
> but you should try 500uS to see if that helps.
>

This was the only thing that helped - I reduced servo period to 500 us
and the motor oscillation borderline shifted from 3660 mm/min to 5114
mm/min.
Reducing servo period down to 250 us did not provide any additional improvement.

>
> What happens if you disconnect the PID (and the motors from the
> machine!) and setp bldc.0.value 0.95 ?
>

I did the following:
# net motor.00.command  pid.0.output  =>  bldc.0.value
setp bldc.0.value 0.95

Result: nothing. Motor does not move.

If I change back:
net motor.00.command  pid.0.output  =>  bldc.0.value
# setp bldc.0.value 0.95

Then I can jog motor.

I tried 3 times switching back and forth - with PID disconected and
BLDC value set to 0,95 motor does not move.

2012/1/27 Peter C. Wallace <p...@mesanet.com>:
>
> So if you set the PID comps MAX_OUTPUT to 158 (and PWM scale is 166.67) that
> will limit maximum PWM to the desired 95%
>

I reduced those values and also set max output to be less than 95% of
output scale:
OUTPUT_SCALE =          125
OUTPUT_OFFSET =         0.0
MAX_OUTPUT =            118

It did not provide any additional improvement.

So this far only reducing servo period did help. Unfortunately that is
coming with RTAI error warning messages. I ran latency test for a
while and got 12000 ns max jitter on servo thread.

Viesturs

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