Re: Does control - - max step rate - the ANSWER

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Mariss Freimanis"
<mariss92705@y...> wrote:

> Art put it very well.
>
> The "quality" of the step pulses really matters for how much power
> you will get from a motor. "Ragged" pulse timing robs motors of
> torque that could be applied to a load. Instead it wastes it on
> pointless accel/decel torque loads.
>
> Perfect pulses are evenly spaced at any speed. This never happens

in

> the digital world though you can come very close.
>
> Barring anything else, a pulse generator that can generate
> extraordinary step pulse rates can also be depended on to produce
> very evenly spaced ones at lower speeds.
>
> But how about if you really need high pulse frequencies, what would
> the conditions be? Let's say you have a 1,000 line encoder on a

servo

> motor that has a 6,000 RPM rated speed. 1,000 lines means 4,000
> counts per revolution; 6,000 RPM is 100 revs/sec, so it would take
> 100 times 4,000 or 400,000 step pulses per second to get what you
> need.
>
> Or how about you have a Compumotor drive set a 125 microsteps per
> step and you need 3,000 RPM. That's 50 revs/sec at 25,000 counts

per

> rev or 1.25MHz for a pulse rate. Suddenly a 4MHz pulse rate doesn't
> seem too high. Comfortable but not too excessive as a matter of

fact.

>
> Just remember, nature abhors a vaccum; if something has the
> capability, someone will find a way to fill it. Depend on that.
>
> Mariss

Hi Mariss, Art, others,

I don't see the THANKS you guys deserve come across as often as they
might.

Having read many posts over the last couple years, I seem to remember
a post from Mariss about microstepping and the functionality of
anything much beyond 10x as being miniscule. So, for my reasoning,
looking for more is pointless.

Also, figuring the generalities of available screws, encoders, motors
and drivers, along with physical limitations of mechanical things
bound by laws of physics ( I seem to remember a post from a guy
wanting a 1,000,000 RPM motor....shaft speed surface was near the
speed of light....)

So, even though many, or most of us would shoot for the sweet spot of
currently available technology, there are those who strive for
Maximum Available Technology.

Also, I have been limiting my view into the realm of steppers, not
servos, so from that viewpoint, it seemed a pointless goal.

I'm glad you guys offered the underlying technical data on WHY this
sort of thing might be needed.

I don't think I want to see anyone put a 6,000 RPM servo on a Mini-
Mill anytime soon, but having the options and choices we have today
compared to 10-15 years ago, it boggles the mind what we will
consider archaic technology in 5 years.

But, as Art mentioned, having you guys with the ability and desire to
follow the edge of technology offers benefits to those of us, many
levels removed.

One interesting thing I get from this is that my current Geckos are
designed for WAY more capability than I will probably ever use them
for.

And, I think I can safely speak for the group.

Thanks guys !

Dave
(owner of a bunch of Gecko's and a licensed version of Mach)