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Topics - mTron

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General Mach Discussion / Lost steps - again?
« on: January 27, 2013, 02:28:46 PM »

New to this forum I need your help in a strange problem I experience in my stepper-motor driven Quantum BF20L mill, controlled by Mach 3.043.022. The PC is an elderly Intel P5 machine running at 512MHz; it is dedicated to Mach3 and has no network connections.

At the very beginning of my work with Mach3, about 3 years ago, the motors just screeched and didn't move. It happened quite rarely, say once in an hour's operation and when doing a G0 rapid move under G-Code control. I never had the problem when jogging, even when using the shift-key. I then reduced the maximum speed on all axes from 1500 mm/min to 1200 and also reduced the ramp to now 60 mm/sec/sec. This seemed to cure the problem or at least reduced it to a tolerable frequency.

Recently the problem reoccurred for no apparent reason, several times in an hour. I further reduced speed and acceleration - no improvement. There seems to be a coincidence: Usually when jogging in Step-mode the speed is very low. After a number of jogging moves in both Cont- and Step-mode with and without shift-key (rapid jogging) the speed in step-mode suddenly equals the last feed speed, which may be much higher. I cannot reduce it unless I terminate and restart Mach3. I have never consciously experienced step-loss under G0 when step-jogging speed was low. It also seems to me that when there is step-loss under G0 the usual acceleration ramp has vanished, which would explain why the steppers cannot follow. However I couldn't really verify that.

I then downloaded and installed the newest version of Mach3.043.066 including its driver. It didn't cure my problem, but since then I have a couple of new problems:  :'(

a) When I pause a G-code run run with the space-key I cannot restart the run, i.e. "Cycle Start <Alt-R>" doesn't work any more.
b) When I zero the X- and Y-axes using an edge-finder in the Offsets-screen Mach3 correctly observes its radius. But when I then manually do a "G0 X0 Y0" command via MDI it has forgotten all about the edge-finder offset - the zero position is not where it ought to be.

Then I scanned this forum, but couldn't find anything that helped so far.

Does anyone of you have an idea what I could do next?  ???

Thanks in advance and cheers!


Pages: 1