Re: Question tuning G320 servoamps.

> First, is it realistic to try to setup the servos with no load
> attached? It seems to me that the load of the lead screws will
> significantly affect the dynamics of the feedback loop (i.e. it

will

> change the transfer function and therefore the step and impulse
> responses significantly).
>
> I'm noticing that when I give a jog command in Master5 that when
> the servo is accelerating it sort of does it in fits and starts.

It

> basically starts moving then violently stops then continues
> acceleration. It does this a couple of times before it reaches
> speed....

Erik,
I've used bith Master 5 and Mach 1 on my servo mill with G-320's.
I've settled on and have cut chips with Mach1. Servos have 1Kcpr
encoders, 8K counts / inch. Mach1 drives these at 175ipm. My scope
was broken so I set 320 by ear. First started at suggested pot
locations, adjusted til it stopped oscilating, tried grabbing hand
wheel and jerking, did a little more twidling, and then started long
slow moves and tuned for best noise. The 320's don't do the standard
servo dance of +/1 1 count. They get lazy when they are one count off
so don't try to tune to whine. It doesn't happen.

I suspect the problem isn't your software. Look to your port, is it
driving right? Some ports voltages are marginal. Do a search on the
newsgroup for port levels and buffers. Also, The 320's signal can be
source or sink. I supply 5volts (try game port if you can't get to
drive connector) to common and sink current through the port. Works
much better for me than sourcing from the port to a common ground.

I realy like the pmdx-120 buffer card. Do a google. It bufffers the
signals and does the relay stuff for spindle. About $125 I think.

Hang in. You have the right hardware and software.

Roger