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    Milling motor control - Duet3/PWM Converter

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    • jay_s_ukundefined
      jay_s_uk @Nightowl
      last edited by

      @Nightowl have you adjusted the variable resistor on the top? have you set the VFD up for PWM control? I had to change some of the registers on my VFD to use PWM rather than RS485

      Owns various duet boards and is the main wiki maintainer for the Teamgloomy LPC/STM32 port of RRF. Assume I'm running whatever the latest beta/stable build is

      Nightowlundefined 1 Reply Last reply Reply Quote 0
      • Nightowlundefined
        Nightowl @jay_s_uk
        last edited by

        @jay_s_uk

        If you mean this one (arrowed), no I haven't:

        Screenshot 2022-12-02 at 10.22.48.png

        I'm not using a VFD, though. Just following the instructions from the Ooznest website, the M950 guide and this document.

        I've just noticed point 2 indicates the "5V/24V PWM input signal level option" should be set to 5V, so I'll need to check that...

        Few things are more dangerous than taking the advice of someone who thinks he knows what he's doing.
        I'm still on my learning curve, so take everything I say with caution!

        RatRig 1075, Duet3 MB6HC, Sorotec SFM 1000 PV-ER milling motor, Hobbyist

        1 Reply Last reply Reply Quote 1
        • Nightowlundefined
          Nightowl
          last edited by Nightowl

          One thing I've checked - very carefully, is the voltage across the 12V and GND connectors, adjacent to the 5V PWM connectors, on the Duet control board, and they're only providing 6V.

          Also, the voltage across terminals GND and AO on the PWM board doesn't change when I adjust the motor speed (without the cable connected to the motor, so there's no load) from M3 S1000 to M3 S25000

          That can't be right, surely?

          Also, the jumper on the PWM board is set to 5V.

          Few things are more dangerous than taking the advice of someone who thinks he knows what he's doing.
          I'm still on my learning curve, so take everything I say with caution!

          RatRig 1075, Duet3 MB6HC, Sorotec SFM 1000 PV-ER milling motor, Hobbyist

          jay_s_ukundefined 1 Reply Last reply Reply Quote 0
          • jay_s_ukundefined
            jay_s_uk @Nightowl
            last edited by

            @Nightowl can you just confirm where the PWM is wired to on the duet board?

            Owns various duet boards and is the main wiki maintainer for the Teamgloomy LPC/STM32 port of RRF. Assume I'm running whatever the latest beta/stable build is

            Nightowlundefined 1 Reply Last reply Reply Quote 0
            • Nightowlundefined
              Nightowl @jay_s_uk
              last edited by Nightowl

              @jay_s_uk

              Certainly. The pins on the PWM board are connected to the Out9 VFD\Laser\Servo Drive header:

              Port 1 (PWM in -ve) to 5V_Ext
              Port 2 (PWM in +ve) to Out9
              Port 3 (Power Supply 12-30V) to 12V
              Port 4 (Power Supply GND) to GND
              Port 5 (Voltage Out GND) to GND
              Port 6 (Voltage Out +ve AO) to the motor plug

              There is a loop between Ports 4 and 5, and this is also connected to the GND wire on the motor plug.

              The third wire from the motor plug is connected to the PSU 24V +ve of the PSU.

              Few things are more dangerous than taking the advice of someone who thinks he knows what he's doing.
              I'm still on my learning curve, so take everything I say with caution!

              RatRig 1075, Duet3 MB6HC, Sorotec SFM 1000 PV-ER milling motor, Hobbyist

              jay_s_ukundefined 1 Reply Last reply Reply Quote 0
              • jay_s_ukundefined
                jay_s_uk @Nightowl
                last edited by

                @Nightowl thats where you'll be going wrong then as the header you're using is always on (i think). change numbers 3 and 4. it'll also probably explain why its always on at power up without that relay. i would just wire them to an out connector and switch your M950 accordingly.

                Owns various duet boards and is the main wiki maintainer for the Teamgloomy LPC/STM32 port of RRF. Assume I'm running whatever the latest beta/stable build is

                Nightowlundefined 1 Reply Last reply Reply Quote 0
                • Nightowlundefined
                  Nightowl @jay_s_uk
                  last edited by

                  @jay_s_uk
                  Forgive me, but aren't they 'just' the power supply to the converter? The switch operating the relay (to stop it the motor spinning) is on out7.

                  Also @dc42 posted earlier (I missed it, sorry) that I should connect PWM in -ve to GND (not 5V-Ext)

                  Few things are more dangerous than taking the advice of someone who thinks he knows what he's doing.
                  I'm still on my learning curve, so take everything I say with caution!

                  RatRig 1075, Duet3 MB6HC, Sorotec SFM 1000 PV-ER milling motor, Hobbyist

                  jay_s_ukundefined 1 Reply Last reply Reply Quote 1
                  • jay_s_ukundefined
                    jay_s_uk @Nightowl
                    last edited by

                    @Nightowl ah bugger, you're right. i looked at the diagram wrong

                    Owns various duet boards and is the main wiki maintainer for the Teamgloomy LPC/STM32 port of RRF. Assume I'm running whatever the latest beta/stable build is

                    1 Reply Last reply Reply Quote 0
                    • Nightowlundefined
                      Nightowl
                      last edited by Nightowl

                      All sorted, thank you gentlemen!

                      It was in fact down to way the PWM converter was connected to the Duet board.

                      I'll amend my diagram and publish it here (and delete the earlier one!

                      Few things are more dangerous than taking the advice of someone who thinks he knows what he's doing.
                      I'm still on my learning curve, so take everything I say with caution!

                      RatRig 1075, Duet3 MB6HC, Sorotec SFM 1000 PV-ER milling motor, Hobbyist

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                      • dc42undefined dc42 marked this topic as a question
                      • dc42undefined dc42 has marked this topic as solved
                      • Nightowlundefined
                        Nightowl
                        last edited by Nightowl

                        Here's the updated connection diagram:

                        Screenshot 2022-12-02 at 18.30.44.png

                        ...and this is the code from the config.g file:

                        ; Milling motor and relay configuration
                        M950 R0 C"vfd+out7" L4000:25000 Q1000	; enable router relay on out7
                        M563 P0 S"St George" R0 		; assign spindle 0 to tool 0 and name it St George
                        T0					; select tool 0
                        M5					; ensure motor is turned off
                        

                        Note: I have used this relay to provide mains power to the milling motor, which is activated from Out7 in this case. I guess any Out could be used, but the code would need to be changed accordingly.

                        Many thanks to @dc42 and @jay_s_uk for helping me resolve this, and I hope this diagram will be of use to others.

                        Few things are more dangerous than taking the advice of someone who thinks he knows what he's doing.
                        I'm still on my learning curve, so take everything I say with caution!

                        RatRig 1075, Duet3 MB6HC, Sorotec SFM 1000 PV-ER milling motor, Hobbyist

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