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IndustryArena Forum > CNC Electronics > Stepper Motors / Drives > motors turn on but will not move, wiring diagram incorrect?
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  1. #1
    Join Date
    Jan 2016
    Posts
    8

    motors turn on but will not move, wiring diagram incorrect?

    i am new to posting, i have some experience using a cnc mill, however i have never buit one. I am at a bit of a loss on how to proceed from here. I am building a 30" X 8'-0". this is custom machine and not kit . i have Mach3 set up and assigned and configured all myports and pins. i have also tuned the motors correctly. i checked my XY and Z pins with a multimeter, so my parallel port is working properly.

    the problem: when the power is kicked on the motors lock up, which i understand is a good thing. however when i jog the motors through Mach 3, the coordinates move in the program, but the motors will not turn. i guess the first thing to check is if i wired it correctly. Not being a kit of parts, i wired and set it up myself, so i may have missed something. please see the attached wiring diagram, and let me know if you see any discrepancies. any help on the issue would be much appreciated.

  2. #2
    Join Date
    Jun 2014
    Posts
    777

    Re: motors turn on but will not move, wiring diagram incorrect?

    Wiring looks right to me. You could try disconnecting the enable wires. Most drivers run without. If not that most likely ports pins setup.

  3. #3
    Join Date
    Nov 2013
    Posts
    88

    Re: motors turn on but will not move, wiring diagram incorrect?

    Heres a few things you can try, maybe one or all may end up being needed, try them separately.

    Most breakout boards have LEDs on the outputs for each drive signal, if there not lighting up then go into Mach3 / ports & pins /motor outputs and change step / direction, active high to active low.

    I see no ground on the enable - in the drawing on the 860s , that may cause no movement.

  4. #4
    Join Date
    Dec 2012
    Posts
    199

    Re: motors turn on but will not move, wiring diagram incorrect?

    You mention that the motors lock up when power is switched on. To me this means that the enable is ok, leave it as it is ( even disconnected ) for this moment.
    You connected the - input for dir and step to ground. and the + input to the signal from the breakout board. this also looks fine
    If you have a voltmeter, you could check the direction pin to switch high to low or low to high when you change direction. ( low should be between 0 and 0.5 volt and high above 3.5 volt )
    Start checking on one axis. If jog on mach3 shows a change of coordinates, the software is providing pulses to move the motor.
    If there are no LEDS on your breakout board, you can disconnect the driver and connect a LED with a resistor of 1 Kohm in series between the signal pin ( P2 or P3 for the X axis ) and ground.
    If there are LEDs on the board for the outputs, you can look at them.
    For the direction, you should be able to switch the LED on and of by changing direction on the jogging.
    For the step, you should see the LED light up or dim when you command to move with the jogging.

  5. #5
    Join Date
    Jan 2016
    Posts
    8

    Re: motors turn on but will not move, wiring diagram incorrect?

    thank you everybody for your suggestions, i really appreciate the collaborative efforts among builders.

    i have used a voltmeter while jogging all 3 axis, i get the correct readings (0 in one direction and about 3.5 in the other). i checked the pins directly on the computer port AND on the end of the parallel cable while plugged into the computer. i will try switching the motor outputs to active low and see what happens.

    my breakout board does not have leds for the outputs. however i have read that the DB25-1205 is infamously problematic, perhaps it is a faulty board. before i do that, i will try the LED test as TOINVD suggested. thanks again, i will try these out and let you know what happens.

  6. #6
    Join Date
    Mar 2007
    Posts
    2083

    Re: motors turn on but will not move, wiring diagram incorrect?

    if the breakout board is the one I think it is
    the outputs to the stepper drivers are NPN open collector with a pull up resistor to the positive supply
    the board needs two 5V supplies
    1st, to power the circuit connected to the printer port
    2nd to power the opto isolated outputs to the stepper drivers

    adding links to use one supply compromises the isolation by connecting the signal grounds together

    hi resolution pictures of both sides of the board will make it possible to work out the best way of using the BOB and confirm its the board I think it is

    I'd connect the stepper driver positive step and direction inputs to the BOB's + 5V terminal ( powering the isolated output side)
    and the negative step and direction inputs to the chosen BOB outputs

    the enable input on most stepper drivers is a negative logic input so the drive is active with no input and disabled by an input!!!
    for initial tests don't connect to the enable input

    John

    PS

    if this PDF is your board

    Attachment 305610

    this my first attempt at the BOB's circuit is -

    Click image for larger version. 

Name:	1205 bob.jpg 
Views:	28 
Size:	69.9 KB 
ID:	305612


    wiring mod

    Click image for larger version. 

Name:	modded wiring.jpg 
Views:	16 
Size:	52.7 KB 
ID:	305616

  7. #7
    Join Date
    Jan 2016
    Posts
    8

    Re: motors turn on but will not move, wiring diagram incorrect?

    [QUOTE=john-100;1825782]if the breakout board is the one I think it is

    adding links to use one supply compromises the isolation by connecting the signal grounds together

    hi resolution pictures of both sides of the board will make it possible to work out the best way of using the BOB and confirm its the board I think it is

    I'd connect the stepper driver positive step and direction inputs to the BOB's + 5V terminal ( powering the isolated output side)
    and the negative step and direction inputs to the chosen BOB outputs


    john-100

    see the attached images, to me they look to be the same BOB as you have posted. (see attached images, hope they are of high enough resolution). if it is indeed the same BOB, are you saying i should first delete the driver input enable, and test? or go straight to your updated wiring? thank you for your help, hope to hear back.

  8. #8
    Join Date
    Mar 2007
    Posts
    2083

    Re: motors turn on but will not move, wiring diagram incorrect?

    Hi

    I see the board is the same as the one I found the manual for

    the way the breakout board and stepper drivers are wired with a common Ground
    the stepper driver input current is limited by the BOB's 1K pull up and the 200R resistor in the stepper driver -
    resulting in a very low input current

    active high
    Attachment 305724

    changing the wiring to a common +5V
    the stepper driver input current is limited by the 200R resistor in the driver (as intended by the designer )

    active low
    Attachment 305726
    (don't connect the enable input)

    since you had only wired the +5V to the positive enable terminal that can stay as is

    the only change I think is needed is to re wire the step and direction inputs
    to connect +step and +dir to +5V and the -step and -dir to the correct breakout outputs controlled by printer port pins 2 to 9


    John

  9. #9
    Join Date
    Jan 2016
    Posts
    8
    Quote Originally Posted by john-100 View Post
    Hi

    I see the board is the same as the one I found the manual for

    the way the breakout board and stepper drivers are wired with a common Ground
    the stepper driver input current is limited by the BOB's 1K pull up and the 200R resistor in the stepper driver -
    resulting in a very low input current

    active high
    Attachment 305724

    changing the wiring to a common +5V
    the stepper driver input current is limited by the 200R resistor in the driver (as intended by the designer )

    active low
    Attachment 305726
    (don't connect the enable input)

    since you had only wired the +5V to the positive enable terminal that can stay as is

    the only change I think is needed is to re wire the step and direction inputs
    to connect +step and +dir to +5V and the -step and -dir to the correct breakout outputs controlled by printer port pins 2 to 9


    John
    John, thank you very much for your response. I will test the solution on 1 axis on Friday. I will be sure to let you know the results. I appreciate your help

  10. #10
    Join Date
    Jan 2016
    Posts
    8

    Re: motors turn on but will not move, wiring diagram incorrect?

    John,
    the motors are turning great and everything moves. I have a little motor tuning to work on, but i am getting a good movement for the most part. thanks again.

  11. #11

    motors turn on but will not move, wiring diagram incorrect?

    Hi,

    just wanted to comment, being a new member since this morning. This thread was really helpful since I had a very similar problem. It helped me get my first stepper spinning!!

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