On Fri, 9 Apr 2021, John Dammeyer wrote:
Date: Fri, 9 Apr 2021 11:32:12 -0700
From: John Dammeyer <[email protected]>
Reply-To: "Enhanced Machine Controller (EMC)"
<[email protected]>
To: "'Enhanced Machine Controller (EMC)'" <[email protected]>
Subject: Re: [Emc-users] Small PC for use with 7i90 / 7i96?
-----Original Message-----
From: Peter C. Wallace [mailto:[email protected]]
Sent: April-09-21 10:59 AM
To: Enhanced Machine Controller (EMC)
Subject: Re: [Emc-users] Small PC for use with 7i90 / 7i96?
On Fri, 9 Apr 2021, John Dammeyer wrote:
Date: Fri, 9 Apr 2021 10:34:30 -0700
From: John Dammeyer < <mailto:[email protected]> [email protected]>
Reply-To: "Enhanced Machine Controller (EMC)"
< <mailto:[email protected]> [email protected]>
To: "'Enhanced Machine Controller (EMC)'" <
<mailto:[email protected]> [email protected]>
Subject: Re: [Emc-users] Small PC for use with 7i90 / 7i96?
From: andy pugh [ <mailto:[email protected]> mailto:[email protected]]
On Fri, 9 Apr 2021 at 17:40, John Dammeyer < <mailto:[email protected]>
[email protected]> wrote:
Your photo of the 7I80 is clearer than the one on the MESA site. But I can't
figure out what the difference is between the 7I80DB-
16
and -25. Which one do you have and why?
It's a "16" as it has a 16 k-gate Startan 6 FPGA. The "25" has 25 k-gates.
You can fit a bigger, more complicated, firmware on the 25k one. I am
not sure if any 7i80 firmwares need the 25kgates.
I have the one that I have because that's the one PCW gave me as a
development sample ;-)
Ah! Now that makes sense. Possibly the larger could be used to allow a
non-firmware reprogramming to allow step/dir _or_ pwm/dir on the same two pins.
Right now my MESA 7I92H can't do that while an Ethernet Smooth Stepper with
MACH can.
But that's an apples and oranges comparison from what I understand because of
what happens inside the FPGA on both.
John
You could do this in hal either by using the stepgen as a PDM generator
(assuming the PWM is just filtered to obtain a analog voltage)
or disabling the stepgen and using software PWM (low PWM frequency only)
Thanks for the idea Peter,
In this case it's one of those really cheap 0-10V modules from China. So IIRC,
it's a 1kHz PWM. I'm only able to get 240 Hz at the low end.
How do I set up a software PWM verses step/gen? The adaptor board I built
takes the same two pins and routes it out as step/gen and PWM into the little
module. The Bergerda Servo drive is where a parameter is selected for one or
the other since I bring the analog and the step/gen into the drive.
You can look up the pwmgen manual page, Probably for a 1 KHz PWM filter and
running the pwmgen at the 1 KHz serco thread I would use the software pwmgens
PDM mode (so 50% is 1 ms on 1 ms off) This also depends on being able to
disable the stepgen so this will only work if the stepgen has a higher number
than any needed stepgen.
(because you can enable stepgens 0..N not arbitrary stepgens)
DB-25 for step/dir/select/fault and a small green 2 pin connector for 0-10V
from the module stacked on top. The connection to the Break Out Board is just
those 4 pins.
John
Peter Wallace
Mesa Electronics
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Peter Wallace
Mesa Electronics
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