NJC
Stepper Motor Problem
April 25, 2011 07:13PM
My build has screeched to a standstill because all of my tests with the stepper motors have failed. I am using Gen 6 electronics with Pololu stepper motors.

To test the steppers I hooked up one stepper to the extruder driver and am using Repsnapper to move the extruder. The electronics and firmware seem to be working properly too.

When I click the "Run Extruder" button, the stepper motor clicks very quietly but does not move anywhere. So as far as I can tell, the stepper driver is receiving the command just fine since it will click every time I send the command.

I have tested the voltage reference for the stepper driver on the circuit board and the voltage is correct. Also, I am very sure that I have the stepper wires connected correctly. I measure each coil resistance as 6.8 ohm. I have also tried connecting only one coil to each end of the stepper driver to verify that both coils individually would also cause the stepper motor to click quietly.

All I can think of is that somehow not enough power is being provided to the stepper motors, but I am not sure how to test this. I have all the test equipment available that I would ever need, I just am not sure how to go about testing a stepper driver. Does anyone have any ideas what could be wrong? Or anything else to try? Or does anyone know a way I can hook an oscilloscope up to the motor driver output to test the current and the pulse timings?

Thanks for any help. I am really stuck.
NJC
Re: Stepper Motor Problem
April 25, 2011 07:38PM
If I could delete this post, I would. I figured out the problem. I used the wrong resistor for the Gen6 circuit. I misread the .22 ohm resistor as 22 ohm. Wooops. Sorry about that.

NJC
Re: Stepper Motor Problem
April 25, 2011 07:40PM
The best place to connect a scope is across the sense resistors to see the current waveform.


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