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Author Topic: Smoothstepper USB and z axis  (Read 18175 times)

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Smoothstepper USB and z axis
« on: December 08, 2012, 06:36:23 PM »
I just installled the USB smoothstepper and the x and y axes are humming smoothly.  But while troubleshooting the z axis, and a few missing steps, somehow the configuration has gotten trashed, and both up and down commands cause downward moves.  Is this stored in the smoothstepper.xml file?  What needs done at this point?  The z used to work both directions....I uninstalled the driver an config files, and restarted, but it didn't help.  Not knowing exactly what;s going on software wise, I am in  a quandary here.
Re: Smoothstepper USB and z axis
« Reply #1 on: December 08, 2012, 06:41:18 PM »
Are you certain it is a SW issue ?
Might double check all of the connections along the Z dir. conductors.
Russ
Re: Smoothstepper USB and z axis
« Reply #2 on: December 08, 2012, 06:44:23 PM »
I thought that as well.  I manually changed the direction input on the z driver card, 5v and low, and when software stepped, it went the correct directions.  Then ohmed out the 2 lines back to the end of the parallel cable. It's correct, I changed nothing there.
Re: Smoothstepper USB and z axis
« Reply #3 on: December 08, 2012, 06:48:34 PM »
Thing is, at first it did work correctly, was just diagnosing the z steps lost. I figured out what it was, it's a low torque issue.  But along the way now, something software went awry.

Offline Jeff_Birt

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Re: Smoothstepper USB and z axis
« Reply #4 on: December 08, 2012, 07:03:43 PM »
Typically a stepper motor that starts going one direction only is a result of a broken wire in the stepper cable or a bad wire in the SmoothStepper cable. If you swap the Z-axis and X-axis motors, at the stepper drive, does the problem stay the same of change axis?
Happy machining , Jeff Birt
 
Re: Smoothstepper USB and z axis
« Reply #5 on: December 09, 2012, 01:19:46 AM »
Hmm, weird. It looks like a faulty Intelligent Motion Systems driver, it's a model IM805.  The direction signal acts by dropping the line low, pulling current through an optoisolator onboard.
The series limiting resistors on each line step and direct lines, on the driver's pcb, should be identical, but that one for the step measures 384 ohms, while the other for direction measures 2136 ohms.  That resistor is likely partially open, which would make sense.  Not sure if the optoisolator is also bad, will know soon enough. 
Re: Smoothstepper USB and z axis
« Reply #6 on: December 09, 2012, 01:30:58 PM »
Well I repaired the z axis drive, the tiny current limiting resistor feeding the optoisolator was high ohms. almost open.  Hard to believe I could replace such a tiny part.
Now without the smoothstepper in place, running mach3 without the smoothstepper, all 3 axes operate correctly.   I reloaded the smoothstepper driver, deleted the mach3 plugin and started from scratch and reconnected the smoothstepper.
Now with the smoothstepper in place, every time I try to jog the z axis, I get a Mach3 emergency stop. No movement, The other 2 drives work fine. >:( Powered off, I get an ohmmeter reading between the step and direction pins on the driver of zero ohms.
Something is seriously wrong here, I think the smoothstepper is defective, and in fact is what killed my driver card.
Not a happy camper here.

Offline Jeff_Birt

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Re: Smoothstepper USB and z axis
« Reply #7 on: December 09, 2012, 01:38:39 PM »
I am fairly certain that the SS did not damage your dirver. It simply cannot source enough current to do any damage. Sounds like you have a flakey drive.
Happy machining , Jeff Birt
 
Re: Smoothstepper USB and z axis
« Reply #8 on: December 09, 2012, 01:49:30 PM »
So then why does the SS not work now? Does it simply need reflashed?  Why does it read a short?  I don;t think an opened resistor caused the SS to fail. In fact I know it couldn't.
Re: Smoothstepper USB and z axis
« Reply #9 on: December 09, 2012, 01:51:54 PM »
Clarification, the short ohmmeter reading is reading the ss pins themselves, not the driver. My driver and cabling are fine.  When I disconnect the parallel cable from the ss, the short is gone.