Problem with stepper motor

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Paint Chip
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Joined: Tue Oct 30, 2012 7:43 pm

Problem with stepper motor

Post by Paint Chip »

I just upgraded my system to the new linux/CommandCNC and am currently trying to configure/debug it. My A axis motor, which runs the far side Y axis stepper won't run, It is selected in the configurator and it is checked for reverse direction. None of the polarity boxes are checked. I pulled the plug out and tested the resistance as in the manual - I get the result shown, about 2 ohms on either side-by-side test of the outer two plugs and infinite resistance on alternate ones (1st and 3rd or 2nd and 4th). I swapped the two plugs that go to the Y axis so the one that moved was plugged into the socket on the bladerunner box for the one that didn't move and vice versa. I still get no movement on the far side of the table. The last thing I tried was checking the stepper windings with an led, Curiously, the motors that work don't light the led, the motor that isn't working does (both windings light when tested). Seems like it must be the motor but not sure what is wrong with it - anybody have an idea?
PPLLC 4X8 table w 620 ox steppers on 5 axes
Bladerunner CandCNC w/DTHC II
Hypertherm PM85
BTA Plasma
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Posts: 590
Joined: Thu May 12, 2011 4:28 pm

Re: Problem with stepper motor

Post by BTA Plasma »

3 Options...

1. Your wires have a short
2. Your configuration file is actually corrupt
3. Your drive has a pin screw with a bad thread


Swap motors to see if the problem follows the motor or drive.
Paint Chip
2.5 Star Member
2.5 Star Member
Posts: 108
Joined: Tue Oct 30, 2012 7:43 pm

Re: Problem with stepper motor

Post by Paint Chip »

Well, I swapped motors around and it appears the problem is the motor plug on the far side y motor may be warn/not fully making contact. On swapping drives, I got the all the motors to work and then it didn't when I plugged them back into their assigned slots. After jiggling the plug and getting it fully seated it now appears to work fine. Guess I'll see about getting a new plug. Thanks for your help.
PPLLC 4X8 table w 620 ox steppers on 5 axes
Bladerunner CandCNC w/DTHC II
Hypertherm PM85
tcaudle
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Posts: 1352
Joined: Tue Feb 28, 2012 6:47 pm

Re: Problem with stepper motor

Post by tcaudle »

CommandCNC supports 5 axis but a slaved motor is not an axis. Ther eis no "A" axis unless you have a seperate rotary axis . You assign motor NUMBERS to axis NAMES in the COnfigurator. You slave a motor by assigning more than one motor to an axis. On the older Bladerunner Controller the lables are "X Y Z A etc. The newer ones are Motor 1 motor 2 motor 3 motor 4 and motor 5 (if you have a 5th motor) . A logic assignment is to use X as Motor 1 Y as motor 2 and Z (must be) motor3. Motor 4 is then assigned in the Configurator to the axis it is slaved to (X ot Y )

Make sure you have the assignment right and you do not have an A axis enabled UNLESS you have 5 motors and its the rotary axis.
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