X Axis Stepper Motor Moves One Direction Only

[P. S. Brannan]

My mendelmax 1.5 is moving right along. The extruder is working along with the y and z axis. The endstops work properly as well.


But the x-axis only moves left to right. Whether I signal a positive or negative move it just moves right. This seems impossible.

I'm using the most recent Marlin 1.0.0 and Pronterface.

Any thoughts? I've switched Pololus. Same behavior.

I'm about to swap motors but wondered if any of you have had this problem.

[Colt D. Majkrzak]

Are the stepper’s wired in the correct order?  I might be wrong but I believe if one of the pairs is reversed you could get this effect of the stepper only moving one direction.

 

I believe (again could be wrong) that your typically driving one coil + and one – to give you forward/back, so if you reversed polarity I guess it could occur?

 

 

Best regards,

Colt Majkrzak  F5CI, F5SE

www.newerastreaming.com

www.bitbucketsolutions.com

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[P. S. Brannan]

Well, just for giggles I swapped the motor and the wiring harness with the y-axis. The y-axis still works perfectly. The x-axis does not. So same behavior with 2 different pololu's. 2 different motors. And 2 different harnesses. I think we can now eliminate all of the above as possible problem candidates.

Oh, and both my x_max and x_min are open when I run m119.

I'll take another crack at it tomorrow. In the meantime, thanks for any help or suggestions.

[Sean Mitchell]

If this is RAMPS, have you tried the test firmware available here: http://reprap.org/wiki/File:RAMPSTestCode.pde

It will bounce things back and fourth about 1cm to test the mechanical and electrics   - ignoring endstops and such.

I suspect you have an incorrectly wired x minimum endstop, so the software is registering that you are always at x=0 (and due to another software switch, #define min_software_endstops true you cannot drive below the zero line.  See configuration.h to change this, however fix the actual problem first) .  What does M119 show?

-sean

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========
Sean Mitchell

echo "zvgp...@tznvy.pbz" | tr '[a-m][n-z][A-M][N-Z]' '[n-z][a-m][N-Z][A-M]'

[P. S. Brannan]

I have tested the x-min switch. When it is not depressed M119 returns it as open, when depressed it is returned as active, or whatever the terminology is. I'm not sitting in front of the machine right now so I don't have the exact messages.

I tried manually holding the x-min switch depressed while I moved the x axis in the negative direction. The firmware returned a warning about the negative limit switch being triggered and refused to command the motor to run.

When I released the switch and tried to move the motor left, it moved right. When I tried to move it right, it still moves right. You can move the axis in any direction as long as that direction is right.

If I flip the motor plug on the board, the behavior is reversed. The motor always moves left regardless of the commanded direction.

It appears to me that both limit switches are working correctly since holding either one inhibits a movement command in that direction.

I did find one reference on another group about a shorted pin on the 2560 causing this behavior. I'll take a look at that tonight.

[P. S. Brannan]

Just in case you are curious, and for the benefit of future mendelmaxers, the "dir" pin for the x driver on my ramps 1.4 is shorted to ground. Hence the unidirectional motor.

And can anyone point me to a sane link that describes how I get from this: #define X_DIR_PIN          55 to the actual pin on the board? I'm not seeing it.

On Tuesday, November 5, 2013 9:42:03 PM UTC-6, P. S. Brannan wrote:

[Fabien Rculone]

Hi , 

At the end , how did you solve your problem ?

Thanks

Fabien

[P. S. Brannan]

Sorry for the late reply.  I was looking for another issue when I saw this post.

As it turns out there was a small solder bridge on the RAMPS board that prevented the XDIR signal from changing. I cut out the bridge with a utility knife and all is good.

You can look up the pin number for the DIR signal on the Pololus and check that out with a voltmeter. If it's not changing you've got a problem.

[Paul Fornal]

So just joined the groups as i didnt find a post explaining my solution... i have a Prusa Mendel (i2) had this same problem up was up down was up no matter what i did... checked all switches etc still having the same problem... i ordered a few stepsticks for ramps 1.4 months ago and decided to change the z one... everything back to normal... try a new stepstick... order a few to have handy its been hot the last few days mine apparently blew up while callibrating firmware... one minute fine... next homing in the opposite direction and mangling the frame... took a little bit of work but i am now happily printing again... keep some spare stepsticks if there is interest will link to my guy on ali express i think they were 2$ each including delivery... awesome bargains on ali

[Eric Tremblay]

I got the same problem here can you direct me in the right post so I can see where on the ramp to look for the bridge?

[Eric Tremblay]

My printer is fixed, the problem with my Y axis moving only one way, was that one of the pin from the ramp going in the Arduino was bend and not inserted in the arduino. Bented the pin back straight and done, problem solve!  Now I'm printing!

[Morten Nielsen]

My printer is not a MendelMax, but I had the same issue.

I narrowed it Down to a faulty soldering on the stepper motor itself. I tested it using a cheap multiemter and used the "check for continuity" setting.

Test for continuity on your wires to and from the stepper. One of them might have snapped inside, making it impossible to see.

https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter/continuity