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Author Topic: re reference after e stop/limit switch  (Read 4051 times)

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Offline simpson36

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Re: re reference after e stop/limit switch
« Reply #10 on: November 19, 2009, 02:53:51 PM »
There is little commonality between differnet servo drives. They each have their own way of behaving approaching, during and after faulting.

Some drives will fault and cut power to the motor, but continue to track the encoder and the control inputs and therefor can remain 'homed' even if the motor is stopped. Correcting the fault sends the axis back to the correct location.

You may find a review of various drive beneficial. You can find it with a search on this forum. ALL of the drives I tested do behave the same in one characteristic and that is that a reset, however initiated, causes the drive to loose 'home' and re homing is needed.

In my setup, I have the drive error lines connected individually to the Mach axis limits, but I usually have soft limits active so a limit fault means one of the servos is faulted (usually). Mach is vague about why it stops, but I have remote indicator lights on each servo drive so that I know which one faulted and I have separate reset buttons next to the indicators so I can reset each drive independently.

Still, in practice, I have to say that I agree completely with Hood in that it is safer to just re-home all axis after a fault, just to be on the safe side . . . provided, of course that your fixture setup allows this to happen conveniently. I am finally tuned up pretty well and the only faults I have these days is with stopping a program mid run that has multiple coord offsets in it or when I am debugging a program and where I sometimes have to turn soft liimts off if Mach gets confused by all the shifting around (or maybe it's me that gets confuded . . :-[)

« Last Edit: November 19, 2009, 03:02:28 PM by simpson36 »