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Thread: Steppers Dont Turn - EMC2 ubuntu

  1. #1
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    Unhappy Steppers Dont Turn - EMC2 ubuntu

    Hello! I've recently began my journey into the wonderful world of CNC. How hard could it be? Just buy some motors, drivers, wire it up to a parallel cable, and plug it in. Yeah right.

    Well, now at least I have all the software set up and communicating. I bought these motors and drivers on ebay because:
    1) They were cheap and I just want to play around with designs for a while.
    2) They should work good enough.

    Here is some information from the Ebay seller. It is all the info I have:
    http://www.pacificsites.com/~snyder/stepper.htm
    http://www.pacificsites.com/~snyder/.../CablePins.jpg (I just have 3 motors connected as of now)
    http://www.pacificsites.com/~snyder/Ebay/Esale.jpg (set up similar to this, except with a slightly different power supply, which info can be found here: http://www.phihong.com/assets/pdf/PSA075.pdf)

    I believe the problem is setting the following values in the EMC2 stepper configuration:
    Step Time
    Step Space
    Direction Hold
    Direction Setup

    These should all be times in nanoseconds. Most commercial drivers will come with a datasheet that would list these times. However, since these are hand made, I do not have access to this information. I am waiting on a response from the seller to see if he has any additional information.

    Using any of the preset settings in EMC2, I get noise from the motors and the shaft moves slightly back and forth, but doesn't rotate. Is it a problem with those settings, the power supply, or the motors/drivers?

    I just can't figure this out. Thanks in advance for taking time to read this.

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    Alright, I believe the problem is my lack of doing research before buying things. These motor drivers are "direct drive" meaning the pulse to pin A will make it turn 1 step in that direction, and a pulse to pin B will turn it in the other direction, instead of step and direction pulses generated by EMC2. Is there some way to make EMC work with this? Are there any other controller softwares out there that will do this? (preferably linux)

    I was told I could also build something like this and put it between the driver and parallel cable that would convert the signals appropriately: http://archive.electronicdesign.com/.../figure_01.gif



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    The software stepgen module within emc will do that.

    http://linuxcnc.org/docs/2.4/html/ma...stepgen.9.html

    Look at - type 1: up/down

    sam



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    Quote Originally Posted by samco View Post
    The software stepgen module within emc will do that.

    http://linuxcnc.org/docs/2.4/html/ma...stepgen.9.html

    Look at - type 1: up/down

    sam

    Thank you very much for this information. Is this only available in EMC or is it also usable with EMC2 and the axis interface?

    EDIT: If you have the time to give me a few steps to start me off I'd appreciate it.

    Last edited by _AR_; 06-11-2010 at 03:04 PM. Reason: I have no clue what I'm doing.


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    Exclamation

    GOT IT WORKING. Thank you, samco for pointing me to the manual for stepgen. My motor drivers are actually type 2 (phase-A, phase-B). THANK YOU.

    For future reference, to change to any type of stepgen, (for instance in the core_stepper.hal file) you must change the line:
    loadrt stepgen step_type=0,0,0
    to
    loadrt stepgen step_type=2,2,2 (or whatever number corresponds to the type of your motor)

    and then look down the stepgen manual page that samco linked to and look for restrictions on what commands can be used.
    Further down the HAL file there are lines that dictate the motion control like:
    net Xstep <= stepgen.0.step
    net Xdir <= stepgen.0.dir

    If you have 2 phase (type 2) setup like me, it would change to:
    net Xstep <= stepgen.0.phase-A
    net Xdir <= stepgen.0.phase-B

    or if you have type 1 it would be:
    net Xstep <= stepgen.0.up
    net Xdir <= stepgen.0.down

    And repeat for all axis.

    ALWAYS AN EASY FIX ONCE YOU SPEND SEVERAL DAYS TRYING TO FIGURE OUT WHAT THE PROBLEM IS!

    Thanks again. CNC set up is fun.



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    I just started typing out a long explaination on how to change it... And then got your post!...

    Great work.

    How does it run now?

    sam



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    Quote Originally Posted by samco View Post
    I just started typing out a long explaination on how to change it... And then got your post!...

    Great work.

    How does it run now?

    sam

    Seems to run flawlessly. These small motors dont have great speed, but they work. They move pretty quick before they start skipping steps though, at least good enough for my purposes.

    I was beginning to think that EMC just couldn't support these cheap things. +1 to open source projects! Thanks again for your help, sam.



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Steppers Dont Turn - EMC2 ubuntu

Steppers Dont Turn - EMC2 ubuntu