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Really slow homing

Discussion in 'Controller Boards' started by Ankit Kumar, Jul 10, 2022.

  1. Ankit Kumar

    Builder

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    My stepper motor is homing at an incredibly slow rate, so slow that I can barely detect any movement. What could be the issue?

    Here is my GRBL configuration:

    >>> $$
    $0 = 28 (Step pulse time, microseconds)
    $1 = 25 (Step idle delay, milliseconds)
    $2 = 0 (Step pulse invert, mask)
    $3 = 1 (Step direction invert, mask)
    $4 = 0 (Invert step enable pin, boolean)
    $5 = 0 (Invert limit pins, boolean)
    $6 = 0 (Invert probe pin, boolean)
    $10 = 1 (Status report options, mask)
    $11 = 0.010 (Junction deviation, millimeters)
    $12 = 0.002 (Arc tolerance, millimeters)
    $13 = 0 (Report in inches, boolean)
    $20 = 0 (Soft limits enable, boolean)
    $21 = 1 (Hard limits enable, boolean)
    $22 = 1 (Homing cycle enable, boolean)
    $23 = 1 (Homing direction invert, mask)
    $24 = 100.000 (Homing locate feed rate, mm/min)
    $25 = 500.000 (Homing search seek rate, mm/min)
    $26 = 250 (Homing switch debounce delay, milliseconds)
    $27 = 1.000 (Homing switch pull-off distance, millimeters)
    $30 = 1000 (Maximum spindle speed, RPM)
    $31 = 0 (Minimum spindle speed, RPM)
    $32 = 0 (Laser-mode enable, boolean)
    $100 = 250.000 (X-axis travel resolution, step/mm)
    $101 = 250.000 (Y-axis travel resolution, step/mm)
    $102 = 250.000 (Z-axis travel resolution, step/mm)
    $110 = 500.000 (X-axis maximum rate, mm/min)
    $111 = 500.000 (Y-axis maximum rate, mm/min)
    $112 = 500.000 (Z-axis maximum rate, mm/min)
    $120 = 10.000 (X-axis acceleration, mm/sec^2)
    $121 = 10.000 (Y-axis acceleration, mm/sec^2)
    $122 = 10.000 (Z-axis acceleration, mm/sec^2)
    $130 = 200.000 (X-axis maximum travel, millimeters)
    $131 = 200.000 (Y-axis maximum travel, millimeters)
    $132 = 200.000 (Z-axis maximum travel, millimeters)
    ok
     
  2. Alex Chambers

    Alex Chambers Master
    Moderator Builder

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    Your maximum rates ($110, 111, 112) and your homing rates ($24, 25) are all rather low. $110 - 112 you should be able to increase to about 2500 (they are currently 500) and you should also be able to increase your homing search and locate rates. Try $25=1000 & $24=500.
    Alex.
     
  3. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
    Staff Member Moderator Builder Resident Builder

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    Acceleration is also very low. Compare your values to our Machine Profiles
     
  4. Ankit Kumar

    Builder

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    I'm still kinda struggling with this issue. The stepper moves perfectly fine with commands such as G1 X100 F400. However, it doesn't move at all while homing and just holds torque. Note that my application requires only a single axis, so ignore the Y and Z axes configurations. I would appreciate your help!

    Here is the most recent GRBL config:

    $$
    $0 = 10 (Step pulse time, microseconds)
    $1 = 25 (Step idle delay, milliseconds)
    $2 = 0 (Step pulse invert, mask)
    $3 = 1 (Step direction invert, mask)
    $4 = 0 (Invert step enable pin, boolean)
    $5 = 0 (Invert limit pins, boolean)
    $6 = 0 (Invert probe pin, boolean)
    $10 = 1 (Status report options, mask)
    $11 = 0.010 (Junction deviation, millimeters)
    $12 = 0.002 (Arc tolerance, millimeters)
    $13 = 0 (Report in inches, boolean)
    $20 = 0 (Soft limits enable, boolean)
    $21 = 1 (Hard limits enable, boolean)
    $22 = 1 (Homing cycle enable, boolean)
    $23 = 1 (Homing direction invert, mask)
    $24 = 500.000 (Homing locate feed rate, mm/min)
    $25 = 1000.000 (Homing search seek rate, mm/min)
    $26 = 250 (Homing switch debounce delay, milliseconds)
    $27 = 1.000 (Homing switch pull-off distance, millimeters)
    $30 = 1000 (Maximum spindle speed, RPM)
    $31 = 0 (Minimum spindle speed, RPM)
    $32 = 0 (Laser-mode enable, boolean)
    $100 = 100.000 (X-axis travel resolution, step/mm)
    $101 = 250.000 (Y-axis travel resolution, step/mm)
    $102 = 250.000 (Z-axis travel resolution, step/mm)
    $110 = 2500.000 (X-axis maximum rate, mm/min)
    $111 = 500.000 (Y-axis maximum rate, mm/min)
    $112 = 500.000 (Z-axis maximum rate, mm/min)
    $120 = 80.000 (X-axis acceleration, mm/sec^2)
    $121 = 10.000 (Y-axis acceleration, mm/sec^2)
    $122 = 10.000 (Z-axis acceleration, mm/sec^2)
    $130 = 200.000 (X-axis maximum travel, millimeters)
    $131 = 200.000 (Y-axis maximum travel, millimeters)
    $132 = 200.000 (Z-axis maximum travel, millimeters)
    ok
     
  5. Giarc

    Giarc OpenBuilds Team
    Staff Member Moderator Builder Resident Builder

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    You say ignore the Y and Z, so you are only using the X. The problem you may be having is that the machine is waiting for the Z to home first since Z always goes first. If Z never homes, then X and Y can't start. However, there is a 2 Axis version of firmware you can flash that removes the Z axis.
    upload_2022-7-17_11-42-16.png
     
    sharmstr likes this.
  6. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    And did you recompile Grbl to disable Z and Y homing? The precompiled image for 2 axes would still error out waiting on the 2nd
     
  7. Ankit Kumar

    Builder

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    That was it! I connected the stepper to Z-axis, and the homing started well. However, as expected, homing didn't finish because grbl is trying to also home the other two axes.

    Is there any easy fix for this issue? Something I could edit in the grbl library?
     
  8. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
    Staff Member Moderator Builder Resident Builder

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    Ankit Kumar likes this.
  9. Ankit Kumar

    Builder

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    #9 Ankit Kumar, Jul 17, 2022
    Last edited: Jul 17, 2022

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