Parallel Motors G0 F50000 knocks em out

Charly3Charly3 Posts: 35🌟 Super Member 🌟
Any experiences in high speed operation of parallel motors driven by one driver component like on Z-Axis of A5 ?

My problem - two motors in parallel runs fine, but with higher speed rates I´m running into trouble.

On Z Axis all above default max feedrate Z 15 (M203 Z15) with original T8/L8 lead screws and all above default max feedrate Z7 with T8/L2 lead screws on MKS 1L board and minor higher values on SKS 1.3 board will block the motors.

On belt driven axis X/Y any move of two parallel motors about F50000 (G0 F50000 Y0) will cause that problem - even if parallel mode for higher speed is recommended instead of having them connected in serial mode...


  • Samuel PinchesSamuel Pinches Posts: 2,689Administrator
    Higher acceleration requires higher torque. You can get around this by either decreasing the acceleration (recommended), or by increasing the stepper driver current (you will reach the limit quickly). What acceleration values are you using?
  • Samuel PinchesSamuel Pinches Posts: 2,689Administrator
    edited September 2019
    The max speed may also be limited by the microstepping limit of the 8-bit processor on the A5 motherboard. I don't know what the limit is, but you could also test dropping down the microstepping from 16x to 4x (configure MS0, MS1, MS2 jumpers underneath the stepper drivers, and adjust firmware too) and see if that improves things too.
    Post edited by Samuel Pinches on
  • Charly3Charly3 Posts: 35🌟 Super Member 🌟
    Hi Samuel,

    I´m using SKR 1.3 with TMC5160. 4A max is more than both motors are layed out together for.  ~55°C shouldn´t be too much for the motors either.

    Here´re the moderate setting that keeps the printer alive for sure:
    M201 X300            ; Default Max Acceleration X
    M201 Y300            ;  Default Max Acceleration Y
    M201 Z100            ;  Default Max Acceleration Z
    M201 E1500          ;  Default Max Acceleration E

    M203 X300          ; DEFAULT_MAX_FEEDRATE X
    M203 Y300          ; Default max feedrate y
    M203 Z9              ;was 7 Default max feedrate Z
    M203 E150          ; Default max feedrate E

    M204 P800           ; was 800 X, Y, Z and E acceleration for printing
    M204 T800          ; X, Y, Z acceleration for travel moves
    M204 R1000          ; E acceleration for retracts

    M205 X100              ; Default Jerk
    M205 Y100            ;  Default Jerk
    M205 Z100             ; Default Jerk
    M205 E1.0             ;  Default Jerk

    M201 X500 Y500 will lead into trouble if i do large scaled geometric prints with long straight lines in x or y direction.

    Trouble will occur earlier in SpreadCycle than in StealthChop.
    Microstepping is set to 16 with auto microstepping enabled.

    24 V and 16 microsteps should be a good combination - if I can consider the 2208 torque measurements from here:  4 to 16 steps torque differs in first or second decimal place.

  • Samuel PinchesSamuel Pinches Posts: 2,689Administrator
    I would try halving the acceleration, and maybe reducing the jerk and see if that improves anything?

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