RE: [CAD_CAM_EDM_DRO] Re: PID setting in EMC

This is true as far as it goes, but not quite the whole story. In EMC if
you are using freqmod.o to drive steppers you do have to tune the PID
setup. I know it sounds strange as the G320/340 is maintaining the
hardware servo loop, but EMC looks at the pulse task as a servo loop
also. When it is out of wack from the software side you get follow
errors.

As far as tuning it with the motors bare shaft it will work in that you
can adjust EMC to eliminate follow errors at whatever acceleration and
max velocity you choose. But, the problem is you will have no clue if
the motors and the Geckos will be up to the task at the arbitrary
acceleration and max velocity until you connect it to the machine. Then
if you will find out. If the drives are faulting you will need to
decrease acceleration and/or the max velocity and retune EMC for the new
setting. If the drives are not faulting then you need to try harder
settings and tune again. So basically all the tuning on the bench will
need to be redone under the load of the machine if you are looking to
set it up to just under the max it is capable of.

Tim
[Denver, CO]

> -----Original Message-----
> brenfl,
>
> The G328/340 already performs a PID algorithm. Just treat it as a
> step motor drive and everything will work out OK.
>
> Mariss