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    Milling motor control - Duet3/PWM Converter

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    • Nightowlundefined
      Nightowl
      last edited by

      Just out of curiosity, how do I find out what the Q setting should be?

      Is this information relative to the PWM controller, which is advertised as being 1kHz to 3kHz?

      Thanks

      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 dc42undefined 2 Replies Last reply Reply Quote 0
      • jay_s_ukundefined
        jay_s_uk @Nightowl
        last edited by

        @Nightowl its more relative to VFD

        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

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        • dc42undefined
          dc42 administrators @Nightowl
          last edited by

          @Nightowl said in Milling motor control - Duet3/PWM Converter:

          Just out of curiosity, how do I find out what the Q setting should be?
          Is this information relative to the PWM controller, which is advertised as being 1kHz to 3kHz?

          Yes, use between 1000 and 3000.

          Duet WiFi hardware designer and firmware engineer
          Please do not ask me for Duet support via PM or email, use the forum
          http://www.escher3d.com, https://miscsolutions.wordpress.com

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

            Some progress!

            Using the code below, I can now start/stop the motor with M3 Sn and M5 respectively, but I can't change the speed: it is constant at 4,000RPM, which suggests to me that the voltage required to change the speed isn't there. Possibly a fault with the PWM converter?

            Here's the code:

            ; Milling motor and relay configuration
            M950 R0 C"vfd+out7" L0:25000 Q1000	; enable router relay on out7
            M563 P0 S"Sorotec" R0 			; assign spindle 0 to tool 0 and name it Sorotec
            T0					; select tool 0
            M5					; ensure motor is turned off
            

            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 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

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                            • 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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