Machsupport Forum
Mach Discussion => Mach4 General Discussion => Topic started by: Azalin on January 28, 2023, 12:55:09 PM
-
Hi,
Please see the video first.
I have no idea what happened but this was working before. Now the spindle RPM jumps while running.
Machine is a mill. Spindle is a servo. I confirm the servo drive shows the RPM correctly.
But interestingly when I speed up the spindle the range of the jumping numbers narrows. I mean it gets more stable. But slower RPMs are messy.
What could cause this?
Thanks
https://www.youtube.com/watch?v=1tqyhtybhPc (https://www.youtube.com/watch?v=1tqyhtybhPc)
-
Hi,
what motion controller are you using?
Motion controllers report back to Mach4 every 25ms or so, 25ms being the default cycle time of an ESS. At each cycle the motion controller will report
the number of spindle revolutions and Mach does the calculation. The problem is that the 25ms cycle time is nominal only, it might be 23ms sometimes
and 28ms at other times, with consequent variance of the calculated rpm. In most cases the displayed number is averaged. I would guess that somehow
the averaging strategy has changed.
Craig
-
Hi,
Motion controller is Pokeys 57E on M16D. I didn't play with Pokeys settings for months.
-
Hi,
I doubt that anything has changed in the PoKeys, I asked so I could find out what the cycle time was.
I suspect if there is a change it will be in Mach4. If I recall there is a post on the forum which talked about the averaging applied to the spindle speed DRO,
haven't had any luck finding it so far.
The two things which could affect the DRO in the manner that you have described are 1) the motion controller cycle time is changing, maybe some other process or software
on the PC assuming priority that is causing the motion control plugin to run at odd intervals, 2) the averaging applied to the numeric data has somehow altered.
Craig
-
I'm writing a module for my Arduino based pendant but it's just an external .lua file.
Which parts in Mach4 I can check to see if I can fix?
-
Hi,
Which parts in Mach4 I can check to see if I can fix?
At this stage, I don't know, I'm still trying to find the post about it. I'm hoping someone may remember and chime in.
Craig
-
Is this the thread you are looking for?
https://www.machsupport.com/forum/index.php?topic=35694.0
Hi,
Which parts in Mach4 I can check to see if I can fix?
At this stage, I don't know, I'm still trying to find the post about it. I'm hoping someone may remember and chime in.
Craig
-
Hi Azalin,
I remember hat thread, it was a few years ago now, but no that is not the thread I was thinking of.
If I recall correctly there is a setting, I believe within Mach, that governs the time constant of the averaging algorithm
displaying the spindle rpm.
Craig
-
It's ok Craig.
This is really odd. I played with the numbers in both Mach4 and PoKeys. Nothing worked.
https://www.youtube.com/watch?v=3kztXPBJ3bs (https://www.youtube.com/watch?v=3kztXPBJ3bs)
Edit: There is an encoder test screen in PoKeys config app. When I spin the spindle the spped calculation appears to be correct so I think the problem is in Mach4.
-
Hi Craig,
https://www.machsupport.com/forum/index.php?topic=42282.0
Is this the one?
Hi Azalin,
I remember hat thread, it was a few years ago now, but no that is not the thread I was thinking of.
-
https://www.machsupport.com/forum/index.php?topic=41433.0
This seems also relevant.
-
Hi,
no that is not what I remeber but there is a some good stuff in that thread.
I was of the opinion that Mach4 did the spindle speed calculation and averaging but am now beginning to wonder if
I'm not mistaken, maybe this occurs in the motion controller.
Craig
-
I've raised a ticket on Poscope website.
-
HI,
I've just had a response from Andy, the tech guy at Warp9TD, the manufacturer of the ESS. The ESS handles the calculation and the averaging.....not Mach.
I presume the PoKeys works the same way. In which case the averaging is a feature of your motion controller and you are right to pursue PoLab about it.
https://warp9td.com/index.php/kunena/7-general-discussion/9428-spindle-speed-averaging#31373 (https://warp9td.com/index.php/kunena/7-general-discussion/9428-spindle-speed-averaging#31373)
Craig
-
I figuredit out in a very odd way.
https://www.youtube.com/watch?v=bvMAy_FzZig (https://www.youtube.com/watch?v=bvMAy_FzZig)
Error gain value in PoKeys plugin setting was 256. I tried 64 and it worked. Then I restored it back to 256 and it worked too. Very weird. Must be a PoKeys bug.
-
Hi,
Attached is a screeshot of the ESS configuration plugin, the Spindle tab in particular, note the averaging time setting.
Craig
-
Hi Craig,
I solved the problem actually. Please see my post #14.
Thank you very much for your time and effort.
Suat