RE: [CAD_CAM_EDM_DRO] EMC Encoders

Thanks for the info.

I made an error in my calculations and I actually only need 10,000
steps/sec.

Since I can't buy a 233 anymore, I'll have to use a 700+ so the 10,000 is
doable.

The next question is with the encoders. The steppers that I have are 200
steps/rev with 1000 steps/rev on the encoder. I understand from the EMC
documentation that the numbers need to be the same. What do I do?

I'm replacing a Parker Hannifin AT6400 controller which uses a Motorola
68000 series processor. Any idea what the clock speed would be on that and
how much faster the 700+ P3 would be?

Thanks again.

Ethan


-----Original Message-----
From: Jon Elson [SMTP:elson@...]
Sent: Thursday, August 02, 2001 1:06 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] EMC Encoders

Ethan Vos wrote:

> Thanks for the info.
>
> Questions:
>
> When will your board be ready?

I'm hoping by the end of August, but that may be premature. I have a
couple
of
other production jobs that need to be finished, too. The software
conversion
needed so that EMC can talk to the auxilliary I/O through the real time
section (so that the two separate sections of the software don't step on
each
other's toes) needs to be finished and tested.

> If I buy a new computer can I get an ISA slot?

Only if you make sure it has one, as very few new models do have them.

> What is the highest # of steps per second that EMC will support? I read

in

> the Aug 11, 2000 release notes that it was 5,000, but that was dated July
> 14, 1999.

For software-generated step pulses, it depends on the CPU speed. I think
you can get 5000 steps/sec out of a 100 MHz Pentium with steppermod.o,
but freqmod.o would be slower. A 233 MHz pentium should be able to
do about 10000 steps/sec with freqmod.o.

With my board, it doesn't matter, as the CPU is NOT generating the step
pulses, just telling the rate generator how fast to make them. I have run
it
up to 20,000 step/sec, but that is just the limit on my fastest stepper
driver.
It can go to,300,000 steps/sec on each axis.

>
> What would be the maximum on your board?

300,000 steps/sec, given normal settings for the setup and hold times on
the step/dir signals, and the step pulse width, which are all programmable.

> I have an existing machine with 1000 step/rev motors and 4 rev/inch lead
> screws. The limit of the lead screws is 10 inches per second which would

be

> 40,000 steps/sec. If none of the above work, what's the next step?

Ahh, well it DOES sound like you might want to use software stepping in
the meantime, and wait for my board. by the time you've really gotten
everything
working together, I should have my board ready.

Jon


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