Gecho 210 step multiplier, was Re: [CAD_CAM_EDM_DRO] Stepper Math

Guy,

I think there's some confusion about the Gecho210's step multiplier. The
manual says:

"The G210 has a built in STEP PULSE MULTIPLIER. This circuit puts out 1, 2,
5 or 10 pulses for every input STEP pulse."

This is the opposite from microstepping. It seems like the only use for a
step multiplier is if your system cannot spit out step pulses fast enough to
keep you happy, and or your "gearing" is way off and you need to speed it
up. To me, the multiplier feature of the 210 doesn't seem all that useful.
Am I missing something?

Regards,

Paul R. Hvidston, N6MGN
ACKSYS Engineering
Upland, CA

----- Original Message -----
From: "Guy Sirois" <guys@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Monday, February 25, 2002 2:05 PM
Subject: RE: [CAD_CAM_EDM_DRO] Stepper Math


> Yes, Sean.
>
> the drives can change the number of steps it takes for one revolution of
> the motor.
>
> The common motor is a 200 step/revolution as a base value. When it is
being
> driven by a drive that runs in "Full step mode", it will take 200 pulses
to
> make it turn one rev. This is rarely seen/used.
>
> You are most likely to encounter a drive that runs in "Half-step mode",
> meaning it will take 400 pulses to make one rev. The motor just follows
that
> and stops at every half-step instead of every full-step of its 200 steps.
>
> Likewise, there are drives that run in quarter-step, eight-step, or tenth
> step like the Gecko G201. You are now at 2000 pulses per revolution. Your
> motor runs 10 times slower than on a full-step drive but it is 10 times
more
> precise (theoretically) and most importantly, much more than 10 times
> smoother.
>
> The speed versus resolution is a compromise you have to make, but the
> smoothness factor of fractional step drives is maybe more important,
> depending on your application.
>
> Hope this helps,
> Guy
>
>
> -----Original Message-----
> From: audiomaker2000 [mailto:audiomaker@...]
> Sent: Monday, February 25, 2002 10:22 AM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] Stepper Math
>
>
> Hey all,
>
> I must say that I thought I had this down, but after learning more,
> I think I know less again (funny how that works eh?)
>
> My question is in the relationship between the computer's pulses,
> the drive's pulses, and the step motor's steps...
>
> Let me start with my point of reference so we can see where I'm
> screwing this up....
> The older Nema 42 steppers could be jogged in tenths in the original
> configuration. The lead screws are solidly shrouded on the machine
> so I'd rather not tear it down to get to them to count TPI, but
> based on any realistic thread pitch, I'd say that the motors
> probably had to do more than 200 steps per revolution to advance in
> tenths.
> The first thing I don't get is if the drive can change the amount of
> steps a motor takes in a revolution, or if that is limited by the
> stepper itself? It seems like it should be the drives making this
> decision (universal bipolar motor having it's fields arranged for
> microsteps by the drive), and if this is the case, how does the
> drive know how fine a step the motor is capable of, or doesn't it
> matter because it's all about the drive?
> Or does the Stepper have a finite set amount of steps per revolution
> and the drives simply send generic pulses as fast as they can, with
> the drives that can send them reeeeeally fast being
> called "microstepper drives?"
> Without rewiring, what is the constant here? It seems to me like
> both the stepper and the drive are constant and only the speed of
> the stream of steps from the controller is the variable... is this
> correct? If the drive could be programmable for the size of the step
> (rotation angle), I would understand that because it would shift the
> fields in just the correct way to acheive that advance on the
> stepper, and you would set it to the maximum advance (or step
> resolution) that your stepper could accomplish.
> What I'm missing here is what is fixed and what is variable. Do the
> drives have a set number of field configurations or advances and the
> steppers just follow along so now you have to program your steps per
> revolution based on the drive?
>
> Yikes... I'm lost again.
>
> Sean (I know...just hook the darned thing up)
>
> P.S. By the time you respond to this, I will have visited 5 more web
> page tutorials on steppers, figured it out in 3 conflicting ways and
> started at zero again.
>
>
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