M42 not Recognizing I1 to Invert Behavior

  • Hello,

    I am controlling a MOSFET circuit using the HEATER 3 pin on the GPIO header on the Duet Wifi PCB. Everything works electronically, except the behavior is reversed.

    M307 H3 A-1 C-1 D-1 is set in the config file to make the pin available.

    M42 P3 S255 F500 turns off the circuit and M42 P3 S0 F500 turns on the circuit.

    Adding the I1 has NO effect with the M42 command

    M42 P3 I1 S255 F500 still turns off the circuit and M42 P3 I1 S0 F500 turns on the circuit.

    My firmware is 2.03beta3 (2019-03-25b6)

    Any insight why the I1 has no effect would be appreciated.

  • Should work. Are you sure your I1 is capital i, not lowercase L ?
    Also i reccomend to upgrade to firmware 2.05.1

  • Yes using capital i - i'll try updating to 2.05 - not ready for 3.1.1 yet.

  • updated to 2.05.1 firmware and the same behavior.

    Is there any other file or setting that may be causing this reversed behavior?

  • What MOSFET circuit it is? How is it connected?

  • I am using a 4 channel IRF540 MOSFET Opto Isolated DC Switch.

    From the Duet WiFi 1.03 PCB Expansion header

    PIN 1: +5 VDC to Module + Terminal (VCC +5)
    PIN 2: GND to Module - Terminal (GND)
    PIN 8: HEATER3 to Module Signal (S)

    12 VDC 5A Power Supply to Module POWER (VPP/GND)



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