Re: [Emc-users] Mesa Step Pulses?

gene heskett Wed, 25 Oct 2023 13:18:04 -0700

On 10/25/23 12:13, John Dammeyer wrote:

This might be a silly question but if you only want to move it one step then
does the step line stay high?  When does it go low?  After all the next step
might be in 30 minutes so should it go low in 15 minutes?  That's quite the
lookahead.
Enquiring minds wish to know.  ;-)
John

I'm going to take a SWAG john, and say that in all likelyhood, anincoming edge of either polarity will be a step. It really does notmake any sense to this electronics guy, to do otherwise. You cangenerate them any way you want to, but given the speed limit imposed bythe opto-isolaters used, effectively almost doubling the top speed ofthe motor. Given a high enough psu voltage of course.

-----Original Message-----
From: Peter Wallace [mailto:p...@mesanet.com]
Sent: October 25, 2023 8:35 AM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] Mesa Step Pulses?

On Wed, 25 Oct 2023, Todd Zuercher wrote:

Date: Wed, 25 Oct 2023 15:15:36 +0000
From: Todd Zuercher <to...@pgrahamdunn.com>
Reply-To: "Enhanced Machine Controller (EMC)"
     <emc-users@lists.sourceforge.net>
To: "Enhanced Machine Controller (EMC)" <emc-

us...@lists.sourceforge.net>

Subject: Re: [Emc-users] Mesa Step Pulses?

Peter,

Thanks, But is it even going to be worth the effort?  Since I'm sure the
regular minimum pulse length signal is still going to at least work

albeit

with some possible theoretical performance limitations.  I may not even
require step rates beyond where this is a non-issue?


Well since you can certainly get near square waves at the maximum speed
with the current setup, it doesnt seem that much is gained by always

having

square wave step signals, since the minimum timings are always met.

That said, there is an advantage of square wave outputs in simplifying
setup (since the step length and step space settings are unnecessary)


I've asked the drive manufacturer.  See if they get back to me.

Todd Zuercher
P. Graham Dunn Inc.
630 Henry Street
Dalton, Ohio 44618
Phone:  (330)828-2105ext. 2031

-----Original Message-----
From: Peter Wallace <p...@mesanet.com>
Sent: Wednesday, October 25, 2023 10:36 AM
To: Enhanced Machine Controller (EMC) <emc-

us...@lists.sourceforge.net>

Subject: Re: [Emc-users] Mesa Step Pulses?

[EXTERNAL EMAIL] Be sure links are safe.

On Wed, 25 Oct 2023, Todd Zuercher wrote:

Date: Wed, 25 Oct 2023 12:22:40 +0000
From: Todd Zuercher <to...@pgrahamdunn.com>
Reply-To: "Enhanced Machine Controller (EMC)"
     <emc-users@lists.sourceforge.net>
To: "Enhanced Machine Controller (EMC)"
<emc-users@lists.sourceforge.net>
Subject: [Emc-users] Mesa Step Pulses?

Hello,

It is my understanding that the step pulses generated by Mesa cards
are always the minimum pulse length set by for example
hm2_5i25.0.stepgen.00.steplen, only the space between the pulses is
varied by the step rate, is that correct?

I was reading the manual for the new drive I was planning to use in my
next build and see that the drive calls a preference of a 50% duty
cycle for step pulse inputs.  I am guessing that it may have something
to do with how the drive's pulse filtering system works, such that for
maximum noise filtering and step reliability having the pulse length
be approximately equal to the step spacing gives the best results.

So my questions are;  Would it be possible to make a Mesa card output
a 50% duty cycle step pattern instead of the current default pattern?
And would doing this even be worth the effort?


Its possible with a minor firmware change and LinuxCNC driver change to

enable the mode.


Todd Zuercher
P. Graham Dunn

Inc.<https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2F

http://www.pgrahamdunn.com/%2Findex.php&data=05%7C01%7Ctoddz%4
0pgrahamdunn.com

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%7C0%7C0%7C638338414483169698%7CUnknown%7CTWFpbGZsb3d8eyJWIj
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7C&sda

ta=Zwbdv69ESSXKwXR%2FvXYbyijq1wOtyar%2FYeCMJAr6fgg%3D&reserved
=0>

630 Henry Street
Dalton, Ohio 44618
Phone:  (330)828-2105ext. 2031


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Peter Wallace
Mesa Electronics


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Peter Wallace
Mesa Electronics


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Cheers, Gene Heskett.
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis



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