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Author Topic: Actual Spindle Speed DRO delay  (Read 1158 times)

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Actual Spindle Speed DRO delay
« on: November 13, 2017, 01:46:40 PM »
Running PMDX 411 and Gecko G540 on build 3481 on a lathe.

I have a cheap opto sensor on my spindle that works very well reporting the actual spindle speed as verified with a tach.

I noticed that when I issue a M5 that the Dro that shows the actual speed does not return to zero for about 3-5 seconds from the time that the spindle actually stops spinning.

Does anyone know if this is due to the opto, PMDX or Mach4 not updating?

I was using this DRO value to check to see if the spindle had overloaded and stopped and it was not disabling movement promptly.

Is there a better way to handle this? (I am electronically challenged so hopefully I don't have to create some citrcuit ;D)

TIA

RT
Re: Actual Spindle Speed DRO delay
« Reply #1 on: November 13, 2017, 03:03:05 PM »
Hi RT,
I think you'll find that Mach does a significant averaging on the opto input and will therefore suffer a significant delay.
I believe there is some control over the averaging, you can reduce it but may then encounter problems that it is not
sufficently stable for threading.

A genuine encoder is required to give you the bandwidth that  spindle overload protection requires if you require near instaneous
crash protection.

Craig
'I enjoy sex at 73.....I live at 71 so its not too far to walk.'