Encoder Scale Problem - Reporting Wrong RPM
22 Jul 2016 21:31 #77854
by russtuff
Replied by russtuff on topic Encoder Scale Problem - Reporting Wrong RPM
I'm having trouble still. I can't get the index pulse alone to report to pyVCP, it seems to only want to report phase-a.
Any idea what I'm doing wrong?
My preference is to only post the index pulse to pyVCP so I don't have to count phase-a at all (due to running way over 50khz).
Any idea what I'm doing wrong?
My preference is to only post the index pulse to pyVCP so I don't have to count phase-a at all (due to running way over 50khz).
# 1 SPINDLE INDEX PPR BUT WITH BELT DRIVE IT'S .54 PPR
setp encoder.0.position-scale .54
setp encoder.0.counter-mode 1
net spindle-position encoder.0.position => motion.spindle-revs
net spindle-velocity encoder.0.velocity => motion.spindle-speed-in
net spindle-index-enable encoder.0.index-enable <=> motion.spindle-index-enable
net spindle-phase-a encoder.0.phase-A
# net spindle-phase-b encoder.0.phase-B
net spindle-index encoder.0.phase-Z
# THESE ARE THE PHASE-A PHASE-Z PINS
net spindle-phase-a <= parport.0.pin-10-in
net spindle-index <= parport.0.pin-11-in
# THIS TIES PHASE-A TO INDEX FOR SINGLE SENSOR SETUP
# PHASE-A IS REPORTED EVEN THOUGH I'M REFERENCING PIN-11
net encoder-output parport.0.pin-11-in => encoder.0.phase-Z encoder.0.phase-APlease Log in or Create an account to join the conversation.
22 Jul 2016 21:53 #77856
by PCW
Replied by PCW on topic Encoder Scale Problem - Reporting Wrong RPM
As I mentioned before, the software encoder will not reliably detect the index of a high resolution encoder
its really the same problem as counting the "A" line, the pulse is to short to detect reliably at the base thread sampling rate
Some companies make pulse stretchers (one-shots) to solve this issue
Also a index that not on the spindle itself or geared 1:1 to the spindle cannot be used for threading
or rigid tapping (and rigid tapping needs a full 3 wire encoder)
its really the same problem as counting the "A" line, the pulse is to short to detect reliably at the base thread sampling rate
Some companies make pulse stretchers (one-shots) to solve this issue
Also a index that not on the spindle itself or geared 1:1 to the spindle cannot be used for threading
or rigid tapping (and rigid tapping needs a full 3 wire encoder)
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23 Jul 2016 02:28 #77864
by russtuff
Thank you. I figured the index pulse itself would be easy enough to count at high RPM. I'll consider this thread closed.
Replied by russtuff on topic Encoder Scale Problem - Reporting Wrong RPM
As I mentioned before, the software encoder will not reliably detect the index of a high resolution encoder
its really the same problem as counting the "A" line, the pulse is to short to detect reliably at the base thread sampling rate
Some companies make pulse stretchers (one-shots) to solve this issue
Also a index that not on the spindle itself or geared 1:1 to the spindle cannot be used for threading
or rigid tapping (and rigid tapping needs a full 3 wire encoder)
Thank you. I figured the index pulse itself would be easy enough to count at high RPM. I'll consider this thread closed.
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