Hi,
I'm sure it's wrong to stop the impulse step instantly.
I agree, if the pulses were to stop immediately it would imply an infinite acceleration. But isn't that exactly what you have described as the fault?
That the deceleration is that violent that the servo faults?
I use other CNC systems, different manufacturers
That may be so but remember that Mach is not a feedback control system, it can't because Windows is not a realtime environment.
Lets say for example that a move involving the X and Y axes is planned. Mach will plan the trajectory and commit pages of motion data to the motion controller,
one page of position data for every 1 ms of the move. During this move you hit <CycleStop>. If Mach aborts the remainder of the move Mach no longer knows
where it is. It knew where it was at the start of the move and it knows where it was supposed to be by end of the move but it has no idea how far along the move it
got when you hit <CycleStop>. I suppose if the motion controller reported the position of its axis motors then Mach could recover its position, after all this is
exactly how G31 probing works.
Mach is not a feedback control system so the motion controller does not report back to Mach in the normal course of events which includes TO MY KNOWLEDGE
ONLY <CycleStop>.
Lets say that we wanted <CycleStop> to introduce a graceful deceleration phase. First mach would have to abandon the remaining portion of the existing move
and then recalculate the pages of position data required to decelerate the axes. The communication delays between Mach and the motion controller and back again are
way too slow for that to work.
If you use a FeedHold, the machine will stop after a long distance, this is not correct.
I agree it is not desirable but I believe it has to work that way. I reason it that because a deceleration phase is built into the planned move and given that Mach cannot go back
and recalculate the move once its already been committed to the controller the ONLY way to decelerate is to allow the current move to complete and THEN stop.
A I said earlier this is based on my understanding of how Mach works, I am by no means sure. I'm interested how you think it works. Its interesting that you claim that
you have had issues with Mach3 and Mach4....could it that this constitutes an explanation why that should be so?
The laser cutting machine and milling machine are different machines and work differently
I am not convinced this is true. What is true is that Laser requires very VERY high accelerations which make a problem that happens with a mill way WAY worse in a Laser,
but they are both affected by the same phenomenon.
Craig