Re: Two Q's: Servo Hum and FreqMod issues

A 150 cpu seems a little slow for FreqMod. What may be happening is as
you ramp up to speed your cpu can't process and send pulses evenly.

I never used FreqMod ,.. I found that tuning gecko's was easier than
playing with FreqMod's ini file.

One thing worth noting ,.. during wiring and testing my mill I noticed
a rumbling / grating sound. I could feel it by grabing the lead screw.
Turned out to be noise on the encoder line. Just enough to cause this
but not enough to fault the drive (less than 128 pulses)

Frank

> > > > #1 - I've got my servos working well on the bench. My maximum
> > > > velocity is set to .60 ips, which should be within the range
> of my
> > > > servo motors. When I jog, say by running a "G0 X10", the
> motors
> > > > accelerate on a nice conversevative acceleration profile.
> When
> > > they
> > > > reach their max velocity they start to ruble/hum.
> > > >
> > > > So Q#1: is this normal?
> > > >
> > > > I assume this is normal because the servo drive is doing is
> > > feedback
> > > > loop thing, and breaking the motor to prevent it from going
> too
> > > > fast. Even though I've already tuned my motors using the
> gecko
> > > > osciloscope method, I want to be sure that this isn't a
> symptom of
> > > > being out of 'calibration'.
> > > >
> > > > #2 - I'm using steppermod right now, and all works perfect.
> When
> > I
> > > > switch to FreqMod with a period of .000025 (150mhz pc) and
> > > > STEPPING_TYPE=0 (drn, step), funny things happen. When I run
> a
> > > > command like "g0 x5", the motor seeks to about where 5" would
> be,
> > > > but then the motor reverses and slowly seeks backwards and
> doesn't
> > > > stop.
> > > >
> > > > So Q#2 - any ideas why freqmod is behaving badly.
> > > >
> > > > Thanks to all. Have a great weekend.
> > > > Jake