help with steppers

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  • May 19, 2015 at 12:06 am #7715
    jdcuervo
    Member

    Hi!

    i just got a tinyG a few days ago, had many issues trying to put the steppers working fine. i have 3 nema23 maped to x and y axis, and a nema17 to z. just realized they were wrong wired.
    when i was ready to run my machine, z axis started to make weird noises, like a hammer, also moves erratic. the other axis were fine. i could say i have read all the topics about the troubleshooting, double checked wiring, config and so on but i could not put that motor working. so i decided to change my power source from 12v to 24v as recommended but something far weird happened, all my steppers are making that “hammer” noise, i went back to 12v config but nothing happends.

    I have checked my power source and it seems to be fine, it’s a meanwell 24v 10amps.
    I have checked and changed all my steppers from positions, also i replace them with some new.

    Please help as i’m lost!

    Thanks,

    John

    May 19, 2015 at 8:54 am #7716
    jdcuervo
    Member

    there’s also a weird behavior shown in the board, when i use chilipeppr to energize al the motors, not all the green leds light up, sometimes 2 or 3 or non, always is different and you can notice this as well on the motors, some of them get energized and some not, this used to not happend. it seems to be a problem related with PWM as the red light sometimes does not seems to be on.

    May 19, 2015 at 6:23 pm #7718
    cmcgrath5035
    Moderator

    Welcome.
    Lets work backwards, starting with your second post.
    Motor LEDs – These are not definitive on/off indicators. The LED is connected to one lead on the stepper; if the stepper is moving, the LED will flash as that phase winding toggles on and off. If the motors are static, that lead may not be energized in the current position. Bottom line, Leds are only a useful indication when the motor is in motion.

    PWM-the PWM LED will be on when the PWM phase is greter than 0.
    Unfortunately, the default value of $p1pof=0.1 (“off” phase = 10%); some pwm drivers like it that way but it does light the led.

    You hammering sound is likely a parameter settings issue.

    Please post your settings for a review. See:

    Also, hammering can be caused by low settings of the power POTs. Have you adjusted them?

    • This reply was modified 9 years, 6 months ago by cmcgrath5035.
    May 19, 2015 at 9:41 pm #7720
    cmcgrath5035
    Moderator

    Also, please tell us a bit about your machine.
    Belts driven (e.g. ShapeOko) or screw machine?

    If belts, try releasing your X and Y belts, let the steppers spin free, see if motors have same issue.
    If screw, you could loosen the coupling screws to allow motor to spin freely in the coupling.

    • This reply was modified 9 years, 6 months ago by cmcgrath5035.
    May 20, 2015 at 4:25 pm #7722
    jdcuervo
    Member

    Hi! sorry for the delay.

    i’m using a OX kind of machine (from openbuilds). i have checked all you have asked, i’ve adjusted the POTs, copy settings from shapeoko and nothing seems to be working.

    Yesterday i did something that at least in here we do when electronics seems to not be working, i unpluged all the cables from the tinyG for at least 5 hours, when i plug them again, machine started working again, just x and y axis, z is not working at all, i did many tests to the machine and everything was ok with x and Y. this morning i was kinda happy as machine performed pretty well the day before, so i plug some endstops that were missing in my machine, when i switch on tinyG again, the problem with steppers came back, that’s why i think i have a problem related with electricity or ground, don’t really know.

    My settings:https://www.dropbox.com/sh/7uw2a3nc7ttdbu0/AAB8Cz0X5YjBnYkhRIGIP0mYa?dl=0

    There’s also a wrong behaviour with endstops, when they get activated, a red light on tinyG starts flashing (SPdir).

    Z axis appears disabled as i intentional did it.

    Thanks,

    John Cuervo

    May 20, 2015 at 4:27 pm #7723
    jdcuervo
    Member

    i have checked some other motors i have, they are brand new and have same problem, so it seems not be related to belts tension.

    May 20, 2015 at 10:27 pm #7725
    cmcgrath5035
    Moderator

    A few observations, sorry, I am travelling so don’t have time for a super deep dive.

    Your X and Y parameters look like they are for a NEMA 17 Machine.
    $xtr and $ytr=36.54 won’t cause your ‘hammering’ issues, but will likely not be accurate. What size pulley on your NEMA 23 steppers (or did you change to NEMA 17?
    Do you really have NO limit switches?
    Most folks wire NC.

    On any given axis (X,Y or Z), only one limit can be home as well.
    Usually, Xmin, Ymin and Zmax are designated as ‘home’.

    I would suggest you turn off limit and homing all together and get the axis moving and jogging first. Limits add a layer of complexity to the discussion.

    releasing the belts from the pulley was not a tension issue, rather to ensure that the machine was not binding up and demanding too much torque from the motors. Can your freely move the X, Y and Z axis by hand?

    In general, your parameters look OK, with the exception of these questions.

    You mention “un-Plug”, are you using preformed interconnected cables, something yourself, Ox Kit, ?
    Something sounds flaky with your Z, but it could be limit related maybe.

    By the way, flashing SPDir led means the tinyG is stuck in boot loader.
    Likely because of the Limit and Homing settings. What do you mean when you say ‘activated’? You manually operate the limit switch? Does a tinyG reset return tinyG to sanity?

    • This reply was modified 9 years, 6 months ago by cmcgrath5035.
    May 21, 2015 at 7:13 pm #7727
    jdcuervo
    Member

    Thanks for your answer!

    First, i have NEMA23 on x and y axis, i have GT2 20 tooth pulleys, my limit switches are magnetic optical, as i’ve read they will work well as NO or NC just i need to configure them, so will no problem to change them to NC. I read a forum about limit switches in synthetos and many things are clear right now.

    Problems with steppers happened before i put on limit switches. so i will discard problems related to steppers with limit switches.

    I’m able to move freely x,y and z, there’s no problem with it and some days ago machine was performing so well, i put it working for at least 4 – 5 hours, problems happened when i unplug cables.

    Yes, i did something with connectors, so you can easily plug or unplug them (i’m trying to start a bussines so that’s why too much effort)

    when i said activated mean when machine activates the endstop, when it reaches the maximum travel limit.

    And yes, when i reset tinyG it cames back to sanity. i saw in you forum that when the endstop reach the limit, it sends a command to tinyG to block all movements and SpDir starts flashing, but it is normal the “need” to do a reset in order to unstuck tinyG?

    Sorry if i’m not clear with all my statements.

    Thanks again,

    John Cuervo

    May 22, 2015 at 7:43 am #7731
    cmcgrath5035
    Moderator

    it sends a command to tinyG to block all movements and SpDir starts flashing, but it is normal the “need” to do a reset in order to unstuck tinyG?

    Simple answer is: yes, tinyG reset is required.
    When a limit is fired, it is sort of a ‘panic stop’, all information about zero location, etc is lost. Best way to recover is to manually drag the gantry away from the limit, then reset. that sets a new (0,0,0) point. then jog, etc from there.

    OK, understand your setup a bit better; The magnetic Limits do seem to work fine for folks. NC setup is somewhat more noise immune than NO, but not clear if noise is really an issue for you.

    A 20 tooth MXL pulley covers 2mm(pitch) x 20 = 40mm/rev, So $xtr and $ytr should be 40mm for starters, then calibrate(tweak) from there.

    So, do the motors still hammer with the Limit switches turned off?

    May 22, 2015 at 9:31 am #7733
    jdcuervo
    Member

    Thanks,

    Yes they still hammer and make erratic movements.

    yesterday i disconnected all cables, motors, endstops, power and so on and today i reconnected all of them and power on tinyG, surprisingly X axis was working ok and in Y axis just one motor was ok, the other couldn’t get energized, Z axis not working at all.

    one could say there’s a problem with the connectors but this was happening before i arrange my connections.

    Limit switches are turn off but problems still there. switches are optical, there’s not such a thing like “magnetic optical” (me mistake).

    thanks for your answer.

    John

    May 22, 2015 at 7:44 pm #7734
    cmcgrath5035
    Moderator

    Hmmm, the easy comment is that is sound like connection issues, but you are already chasing that.

    Just curious, what voltage are your running tinyG and motors at?
    I do recall, a while ago, someone who had a PS that went int current limiting whenever motors were turned on – was a bad PS.

    Have you tried monitoring the tinyG input when motor motion is called for?

    May 22, 2015 at 8:56 pm #7736
    jdcuervo
    Member

    I agree with you about connection issues, what i’m going to do right now is to change all my wires, i found a nice 4 wires double shielded cable that i’m going to use to wire everything again, also get this 4 pin aviator type connectors.
    i’m runnig them with a 24v right now, it’s a meanwell PS i have checked the PS itself and is working right, i work in a LED company so i use them in some LED arrays, i haven’t checked them on the oscilloscope yet.
    I haven’t checked the tinyG input as i’m pretty afraid to burn the board (i’m the kind of guy afraid to electricity).

    I remark the issue related with cables and connector as today i twisted a cable and a motor that wasn’t working start working, really weird thing man!

    i also put tinyG in a metal box suspended with some magnets i use for LED arrays, they are kind of screws isolated with a magnet on one side so they stick so nice to the metal case and gives tinyG sort of 5cm space from bottom to top so air flow mantains the board so ventilated.

    I’m going to check everything you have said and put the results right here.

    Mnay Thanks,

    John Cuervo

    May 23, 2015 at 7:00 am #7737
    cmcgrath5035
    Moderator

    Just so I am clear, the PS issue one user had was premature current limiting; the static output measured OK, but any dynamic motor load would cause the PS output to drop to a low voltage. The chances are slim that that is your issue.

    If you can, as an experiment, wire the motors directly to tinyG and see if the spin up properly.

    Good luck with reconfiguration effort.

    May 24, 2015 at 11:17 pm #7745
    jdcuervo
    Member

    Hi!

    Problem solved.
    Related to cables and connectors. wired up everything again and now is working pretty good, just calibration issues and “mechanical” sounds that can be solved.

    This is what i think i did wrong:
    1- mix two different sizes of cables, awg 20 and 22, never thought it could be a problem.
    2- used cheap plastic connectors
    3- used an epoxic compound to glue all terminals, seems this was somehow interfering with performance of tinyG.

    What i’m using now:
    1- double shielded awg 20, same as all my motors.
    2- 4-pin aviator type connectors.
    3- i put a piece of plastic between tinyG and casing box, so is isolated.

    Thanks for all your help.
    Hope me mistakes can help somebody with same problem.

    John Cuervo

    May 25, 2015 at 6:42 am #7746
    cmcgrath5035
    Moderator

    John
    Good to hear, thanks for summary to help the next builder.
    Make sure to ground your cable shields at only one end – the tinyG end

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