random homing in opposit direction
07 May 2015 14:47 #58468
by bjames28
random homing in opposit direction was created by bjames28
A LinuxCNC user reported a strange behaviour of his mill:
Sometimes the machine starts the homing in wrong direction on all 3 axes. When moving the axes from the keyboard, all is OK.
Rebooting the PC/machine dosn't help.
It happens randomly, in most cases the homing is done correctly. After the homing is completed well, the mill works as expected.
LinuxCNC ver. 2.6.x., LPT based control with custom BOB, stepper motors.
I'd vote for electrical noise or similar, hard to image that software issue could cause this.
Do you have any ideas?
Sometimes the machine starts the homing in wrong direction on all 3 axes. When moving the axes from the keyboard, all is OK.
Rebooting the PC/machine dosn't help.
It happens randomly, in most cases the homing is done correctly. After the homing is completed well, the mill works as expected.
LinuxCNC ver. 2.6.x., LPT based control with custom BOB, stepper motors.
I'd vote for electrical noise or similar, hard to image that software issue could cause this.
Do you have any ideas?
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- bernie_nor
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07 May 2015 19:26 #58479
by bernie_nor
Replied by bernie_nor on topic random homing in opposit direction
Hi,
I think this is a problem with the gnd og common signal shared by the stepper motor drivers. I would check the direction signals with a multimeter when running the machine. Check at the driver end of the cable. You will most likely not see the problem on the BOB side of the wiring.
Cheers!
Bernie
I think this is a problem with the gnd og common signal shared by the stepper motor drivers. I would check the direction signals with a multimeter when running the machine. Check at the driver end of the cable. You will most likely not see the problem on the BOB side of the wiring.
Cheers!
Bernie
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07 May 2015 20:38 #58482
by andypugh
Replied by andypugh on topic random homing in opposit direction
If the machine thinks that it is already on the limit switches then it will go straight to the latch move, which is typically in the reverse direction to the search move.
So, the first thing I would check is that the homing sensors/switches are actually powered and working properly.
So, the first thing I would check is that the homing sensors/switches are actually powered and working properly.
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