Re: [CAD_CAM_EDM_DRO] Re: wiring Gecko drivers

theokspindoctor wrote:

>Another question. The 201 Gecko puts out 2000 steps per
>revolution. My motors are maxing out at 20 inches per minute with
>6000 pulses per second. Anything higher stalls the motor and it will
>only cry with no movement.
>

Ah, now we are getting to the heart of the problem. The motor stalls!

What power supply voltage are you using? (I was using 49 V on the ones
I set up with the NEMA size 34 motors.)

> Either they are wired wrong or the
>motors can not handle the high pusle rate. Would I be better off
>with the Gecko 210. It seems from the Gecko website that instead of
>fewer pulses the 210 can put up to 10 times more ( up to 20000 steps
>per revolution), so that will not solve my problem.
>

No, other way. It takes LESS step/rev, effectively REDUCINT the
microstepping
factor. But, as long as the computer/controller is not limiting the step
rate, then the 210 does noting for you.

> Am I correct in
>this assumption? or is it that it can go down to 200 steps per rev
>which would be better for me.
>
>

Yes, it can, but I really don't think this is going to fix your problem.

One thing I would do is connect a set of headphones, with perhaps a 1000 Ohm
series resistor between the Gecko's +5 VDC and STEP terminals. Then, listen
to the tone as you jog the machine into the speed range where it has a
problem.
Does the tone rise and fall like slide whistle (ie. a very clean tone)
or like a bunch
of angry bees (a raspy, buzzing noise with little tone to be heard)? If
the former,
it has to be the motors (unless it is due to the lack of capacitors or
the improper
adjustment of the midband resonance damping). I'm having a problem
understanding
why it is crapping out at only 6666 microsteps/second. But, if you hear
the buzzing
noise instead of the clean tone, then your step pulse train is not
"smooth", ie. the
timing between step pulses is varying greatly, and this will cause the
step motors
to lose sync. With an outboard step pulse generator, this should NOT be
happening,
but maybe it is due to some setup problem. I'd remove the current set
resistor, as it needs all the current it can get. I can think of a few
tests to try.
One obvious one is to remove the timing belt and see if the motors will
run at
higher speeds with no load. Another is to convert to a 1:1 drive
scheme, which is
recommended for most stepper setups. You likely will still have the
stall at nearly
the same motor speed, but that will now be near 40 IPM. More power
supply voltage
will also likely help.

Jon