Geckodrive external



  • Due to us using a large stepper motor for our z axis (a 4A nema 34), we are going to use an external driver, a gecko G203V.
    Just need a little help of connecting it.
    The connectors on the driver are as follows:
    1- power gnd, 2 - 18to80vdc, 3-6 are for the motor, 7 - disable, 8 - DIR, 9 - Step, 10 - Common, 11 & 12 current set

    The wires from the driver to the motor is fine, the 2 current set connectors on the drive is done using a resistor.
    But its the wiring from the expansion board to the driver that we need help with.

    Looking at the Using external drivers page, I guess that pin 5 goes to no 9 on the driver, pin 6 connects to no 8 on the dirver.
    That is as far as we have got


  • administrators

    Connect Common to ground on the Duet, and disable/dir/step to a set of enable/dir/step pins on the Duet expansion connector.



  • is the disable pin on the driver used?
    I have seen on web that people with CNC machines not using this pin
    When I use the pin, the motor free wheels and the error light come on, and when I don't use it, it doesn't, and there is current going to the motor (so it isn't free wheeling)

    Gecko say this terminal will force the winding currents to zero when tied to the step and direction


  • administrators

    You don't have to use the disable pin, it just allows you to disable the motor with M84 which might be useful, or might not, depends on your setup.

    Most stepper drivers have an enable pin (rather than disable) so the polarity is probably the other way around. You can set this polarity using:

    https://duet3d.com/wiki/G-code#M569:_Set_axis_direction_and_enable_values

    It looks like yours is active high.



  • With the microsteps, does it come from the geckodrive which is 10microsteps, or the onboard driver on the wifi?

    We are struggling with steps per mm with our z axis with a 20mm pitch leadscrew.

    Wondering if it is the pulse? at the moment the command is M569 P5 S0 R1 T2 not sure if that looks right or not. There aren't many examples online with a T value


  • administrators

    The microstepping is determined by your external driver.

    If the amount of Z movement is not consistent then you may have the Z acceleration or jerk set too high.



  • we might of cracked it, but the paneldue screen is now just a blank screen. Is there some kind of way to do like a factory reset (like hold down the reset button for x seconds)?


  • administrators

    If PanelDue is showing a black screen, either there is a hardware fault (most likely a blown backlight inverter on the panel) or you have erased the firmware.

    You can check whether the PanelDue controller is commanding the backlight on by measuring the voltage on the LED_A pin of the TFT panel. It should be +3.3V for full on, and 0V for off.

    If you have erased the PanelDue firmware, then if you connect its USB port to a PC you should see the "Bossa Port" in the Ports section of Windows Device Manager (others can translate that to what you see under Linux or OSX).

    HTH David


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