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Encoder Scale Change
3 years 2 months ago #278833
by Nitram
Encoder Scale Change was created by Nitram
Hello.
I am changing my lathe spindle encoder.
Original is a disk with 120 slots measured by photo-interrupters and an index.
Going to a magnetic encoder, quadrature, 3600 ppr.
Both encoders mounted directly on the spindle (no pulleys/belts/gears).
With the disk, HAL encoder counter-mode pin (encoder.N.counter-mode) was set true, and input was simply the bit as the photo-interrupter saw the passage of a slot.
Physical input to 7i76e to is via the A+ pin on the card.
Scale is set to 120.
With the magnetic quadrature encoder, physical wiring will be all of the pins, A A/ B B/ etc.
So my question is, when I install the magnetic encoder and after I set counter-mode to off, do I set the scale to 3600 or do I set the scale to 14400 (3600*4)?
I.e. after counter mode is set off and therefore quadrature mode is on, does LCNC "know" to expect to see 4 states per pulse and therefore scale is 3600, or not (in which case scale would need to be 14400)??
And as an aside, am I right in saying that the scale may now need to be a negative number to ensure correct rotation direction is sensed depending on how I end up mounting the magnetic ring encoder (i.e. face in vs face out and therefore B leading A rather than the other way around).
Thanks,
Marty.
I am changing my lathe spindle encoder.
Original is a disk with 120 slots measured by photo-interrupters and an index.
Going to a magnetic encoder, quadrature, 3600 ppr.
Both encoders mounted directly on the spindle (no pulleys/belts/gears).
With the disk, HAL encoder counter-mode pin (encoder.N.counter-mode) was set true, and input was simply the bit as the photo-interrupter saw the passage of a slot.
Physical input to 7i76e to is via the A+ pin on the card.
Scale is set to 120.
With the magnetic quadrature encoder, physical wiring will be all of the pins, A A/ B B/ etc.
So my question is, when I install the magnetic encoder and after I set counter-mode to off, do I set the scale to 3600 or do I set the scale to 14400 (3600*4)?
I.e. after counter mode is set off and therefore quadrature mode is on, does LCNC "know" to expect to see 4 states per pulse and therefore scale is 3600, or not (in which case scale would need to be 14400)??
And as an aside, am I right in saying that the scale may now need to be a negative number to ensure correct rotation direction is sensed depending on how I end up mounting the magnetic ring encoder (i.e. face in vs face out and therefore B leading A rather than the other way around).
Thanks,
Marty.
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3 years 2 months ago #278834
by PCW
Replied by PCW on topic Encoder Scale Change
Scale would be 14400 (or -14400) for a 3600 PPR encoder (in quadrature mode)
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