4. Stepper settings - Stuttering motors

Stepper settings - Stuttering motors


  • Hello, i am sure this question has been asked many times before. I have previously had great success upgrading my delta printer to a duet board. it was some tweaking in the config file to get it running, but now its running great. So i wanted to upgrade my chinese cartesian to a duet also, but I am going mad tryin to get the steppers to stop stuttering. I have tried to make a new config file multiple times, but i dont see any constistency in changing values and when the motors stutters. Right now my X and Y seems ok, but my Z motors keep making noise, stutter and not going where they are supposed to. Checked for voltage drop, changed to better sd card. I am not sure what settings i am supposed to have on current on the motors, since i cant find the data sheet for my motors. (SL42STH40-1504A). Anyone have a pointer where to look?

    ; Configuration file for Duet Ethernet (firmware version 1.17 to 1.19)
    ; executed by the firmware on start-up
    ;
    ; generated by RepRapFirmware Configuration Tool on Sun Jan 07 2018 18:24:15 GMT+0100 (W. Europe Standard Time)

    ; General preferences
    M111 S0 ; Debugging off
    G21 ; Work in millimetres
    G90 ; Send absolute coordinates…
    M83 ; ...but relative extruder moves
    M555 P5 ; Set firmware compatibility to look like Repetier
    M208 X0 Y0 Z0 S1 ; Set axis minima
    M208 X250 Y250 Z400 S0 ; Set axis maxima

    ; Endstops
    M574 X1 Y1 Z1 S1 ; Set active high endstops
    M558 P0 X0 Y0 Z0 H5 F120 T6000 ; Set Z probe type to switch, the axes for which it is used and the dive height + speeds
    G31 P600 X0 Y0 Z2.5 ; Set Z probe trigger value, offset and trigger height
    M557 X15:235 Y15:235 S20 ; Define mesh grid

    ; Drives
    M584 X0 Y1 Z2:4 ;Set driver map
    M569 P0 S1 ; Drive 0 goes forwards
    M569 P1 S0 ; Drive 1 goes backwards
    M569 P2 S1 ; Drive 2 goes forwards
    M569 P3 S1 ; Drive 3 goes forwards
    M350 X8 Y8 Z8 E8 I1 ; Configure microstepping with interpolation
    M92 X102.5 Y102.5 Z400 E420 ; Set steps per mm
    M566 X17 Y17 Z0.4 E4 ; Set maximum instantaneous speed changes (mm/min)
    M203 X1000 Y1000 Z4 E17 ; Set maximum speeds (mm/min)
    M201 X1000 Y1000 Z4 E750 ; Set accelerations (mm/s^2)
    M906 X1500 Y1500 Z1500 E1500 I50 ; Set motor currents (mA) and motor idle factor in per cent
    M84 S30 ; Set idle timeout

    ; Heaters
    M305 P0 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 0
    M143 H0 S120 ; Set temperature limit for heater 0 to 120C
    M305 P1 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 1
    M143 H1 S280 ; Set temperature limit for heater 1 to 280C

    ; Tools
    M563 P0 D0 H1 ; Define tool 0
    G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
    G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C

    ; Network
    M550 PMy printer ; Set machine name
    M540 PBE:EF:DE:AD:FE:ED ; Set MAC address
    M552 P192.168.1.20 S1 ; Enable network and set IP address
    M553 P255.255.255.0 ; Set netmask
    M554 P192.168.1.1 ; Set gateway
    M586 P0 S1 ; Enable HTTP
    M586 P1 S0 ; Disable FTP
    M586 P2 S0 ; Disable Telnet

    ; Fans
    M106 P0 S0.3 I0 F500 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
    M106 P1 S1 I0 F500 H1 T45 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned on
    M106 P2 S1 I0 F500 H1 T45 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned on

    ; Custom settings are not configured

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  • Also, when changing config file on the web interface, the board reboots. but is all changes active or do i have to power off also?

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  • administrators

    Possible causes of Z motor stuttering include:

    • Z acceleration or speed set too high. Try reducing them to low values. [Edit: you have already done that.]

    • Insufficient motor current. Try 1000mA. If the motors get hot, reduce it. If they are stone cold, you could increase it.

    • Excessive friction or binding of the Z mechanics. Do the leadscrews etc. turn freely by hand?

    • Faulty Z driver. Connect the Z motor to the E1 motor output, use M584 Z4 E3 to remap Z to the E1 motor output, use M906 after that to set the current, then see if it works any better.

    @msn85:

    Also, when changing config file on the web interface, the board reboots. but is all changes active or do i have to power off also?

    That is sufficient to activate the changes. You do not need to power off.

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  • administrators

    PS the 1504 bit of the part number suggests a rating of 1.5A per phase.

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  • ok, thank you for the answer. i have set the current to 1500mA in the config. I have two z motors. First i tried running them in series, did not get desired result, so now i am trying running one of the z motors on E1. Sometimes the motors seem fine for a couple of seconds when jogging, then they start again.

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  • When running two Z motors on different drivers, the acc and current settings apply to both motors if they are mapped as Z?

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  • administrators

    @msn85:

    When running two Z motors on different drivers, the acc and current settings apply to both motors if they are mapped as Z?

    Yes, as long as you use M906 to set the current after using M584 to set the mapping.

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  • Hi, I have a similar issue with my noisy dual Z motors , remaped on E1 stepper make the motors quiet but also using only 1 motor on Z solved it..
    All the motors on my printer are the same (42BYGH4812AA), can handle 1,2A and are set to 800mA on XY and are quiet. On dual Z, I try from 800 to 2600mA and nothing change and in single Z it's nice from 800 to 1200mA.
    I don't know if I clear, but do you have an idea why it's like this ?
    Thanks

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  • administrators

    Those motors are relatively low current and high inductance. So if you are using only a 12V supply then there may be insufficient drive voltage to move 2 of them in series other than at low speeds. See the motor calculator at reprapfirmware.org. For those motors, connecting them in parallel may work better than connecting them in series.

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  • Couple things jump out at me with your config.

    M350 X8 Y8 Z8 E8 I1 ; Configure microstepping with interpolation
    Interpolation only works if you set the microstepping to 16X, your running a coarse 8x atm.

    M566 X17 Y17 Z0.4 E4 ; Set maximum instantaneous speed changes (mm/min)
    The XY values look a bit strange here, try setting them to a more normal 200-500 range perhaps? Maybe 100 for Z?

    M203 X1000 Y1000 Z4 E17 ; Set maximum speeds (mm/min)
    A bit slow for the X and Y (16.6mm/s) perhaps? Z is crazy slow at 0.06mm/s not sure how well its going to behave that slow. E is also slow, with direct drive your going to want it much much faster at least the 1500 range.

    Perhaps your config looks like that because your troubleshooting but if not a more normal baseline might rule out the easy stuff.

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