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

Norm,

Hmm, my output/input scale is already pretty high (20000).
StepperMod is working well for me, so I can stick to it. ;)
I just thought that FreqMod's behavor was a bit odd. I suspect its
looking for a closed loop which just isn't there, but as far as I
can tell, my settings are right.

Mariss,

I'll play with my gain a bit. I guess when I tuned them my pulse
generator wasn't putting out enough pulses to really get the motor
spinning fast enough to hum/rumble. Now that I'm hooked to real
software, I get the hum.

Also, I had a question for you. Whats the little 6 pin header near
the test point ground for? :) I notice that there is a small hole
in the case right there. I was wondering if Gecko had some sort of
test connector that they might hook up there. I really wish there
was a way I could expose the test points while the cover was on
(through that hole in the case perhaps?).

I'll probably just play with the knobs again, turning down the gain
as you suggest. If I want to 're-scope' the test point though, I've
gotta deal with unscrewing everything now. And with heatsink
compond all over the back to boot. ;)

Thanks again as always, you guys are all great!

Jake

--- In CAD_CAM_EDM_DRO@y..., "steel2chips" <h5npbmj@c...> wrote:
> Jake,
>
> You are not alone. I see the same thing when using freqmod.
However
> for some reason, if I set the INPUT_SCALE and OUTPUT_SCALE higher
(say
> 8000.0) the problem goes away. wierd...
>
> Norm
>
> --- In CAD_CAM_EDM_DRO@y..., "mariss92705" <mariss92705@y...>
wrote:
> > Try turning the GAIN trimpot down a smidge and see if
the "rumbling"
> > quiets; you may have it up too high.
> >
> > Mariss
> >
> > --- In CAD_CAM_EDM_DRO@y..., "jbordens" <jake@a...> wrote:
> > > Got to questions for you wise folks here in CCED...
> > >
> > > #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