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Offline jve

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encoder feedback
« on: September 26, 2009, 01:00:50 PM »
hi guy
i have a mill and i notice that when i press the reset button on mach3 i am loosing position is it possible to make encoder feedback via 2nd parallel port i have the encoder feed back on my servo drives A+ A- B+B- Z+Z- did any one did this before
regards
jekran

Offline Hood

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Re: encoder feedback
« Reply #1 on: September 26, 2009, 01:03:40 PM »
It is but it will only be for monitoring purposes, not closing the loop. If you are losing position then I would say your servo drives/motors are needing tuned.

Hood

Offline ger21

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Re: encoder feedback
« Reply #2 on: September 26, 2009, 01:09:57 PM »
Are you pressing reset while in motion. If the machine is moving, press pause, then stop. Then, it shouldn't lose position.
Gerry

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Offline jve

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Re: encoder feedback
« Reply #3 on: September 26, 2009, 01:17:24 PM »
Are you pressing reset while in motion. If the machine is moving, press pause, then stop. Then, it shouldn't lose position.
no the machine is in stop is there a way to have encoder feedback with a close loop

Offline Hood

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Re: encoder feedback
« Reply #4 on: September 26, 2009, 01:19:34 PM »
The loop is closed to your drives but at this point Mach is not in the loop. Sorry I didnt see the first part regarding the reset before, how much is it loosing when you reset?
Hood

Offline jve

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Re: encoder feedback
« Reply #5 on: September 26, 2009, 01:21:41 PM »
The loop is closed to your drives but at this point Mach is not in the loop. Sorry I didnt see the first part regarding the reset before, how much is it loosing when you reset?
Hood
i would say about .1 of a mm but it is not always .1mm

Offline Hood

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Re: encoder feedback
« Reply #6 on: September 26, 2009, 01:28:51 PM »
How many encoder counts would that equate to? Seems to me that if its such a large amount then it must be a force of some sort acting on the axis and moving it when disabled. I use a SmoothStepper and have noticed by monitoring my drives software that pressing the reset can lose position but it is only by 1 or max 2 counts of my encoder which equates to 0.00125mm maximum. I have put that down to my drives being disabled and the belts relaxing slightly. I always rehome after I have reset but in reality it would be a lot of resets before I am out of position enough to worry about. If however I had a slantbed lathe then the chances are the axis would move further when the drive was disabled (due to reset being pressed) so at this time the only option would be to rehome after a reset.

Hood

Offline jve

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Re: encoder feedback
« Reply #7 on: September 27, 2009, 09:34:33 AM »
How many encoder counts would that equate to? Seems to me that if its such a large amount then it must be a force of some sort acting on the axis and moving it when disabled. I use a SmoothStepper and have noticed by monitoring my drives software that pressing the reset can lose position but it is only by 1 or max 2 counts of my encoder which equates to 0.00125mm maximum. I have put that down to my drives being disabled and the belts relaxing slightly. I always rehome after I have reset but in reality it would be a lot of resets before I am out of position enough to worry about. If however I had a slantbed lathe then the chances are the axis would move further when the drive was disabled (due to reset being pressed) so at this time the only option would be to rehome after a reset.

Hood
thanks hood
i will take your advice and rehome after a reset

Offline jve

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Re: encoder feedback
« Reply #8 on: October 28, 2009, 02:38:30 PM »
today i notice that I'm loosing position when i hit the flood coolant and minst coolant is this problem from mach3 or from bb I'm using ubob from candcnc

Offline Hood

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Re: encoder feedback
« Reply #9 on: October 28, 2009, 03:12:41 PM »
Sounds like noise may be the problem.
Hood