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    Stall detection with 2 motors

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    • Phaedruxundefined
      Phaedrux Moderator
      last edited by

      You're missing an H value from your M915. Did you calculate it?

      https://duet3d.dozuki.com/Wiki/Stall_detection_and_sensorless_homing#Section_Minimum_recommended_speed_for_stall_detection

      @noisettetbou said in Stall detection with 2 motors:

      M574 X1 S3 ; configure sensorless endstop for low end on X
      M574 Y1 S3 ; configure sensorless endstop for low end on Y

      You say you're using 3.1.1 but your config is using syntax for RRF2.

      Please send M115 and confirm what firmware you're actually using.

      Z-Bot CoreXY Build | Thingiverse Profile

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      • noisettetbouundefined
        noisettetbou @Phaedrux
        last edited by

        @Phaedrux
        09/09/2020 à 21:53:09 M115
        FIRMWARE_NAME: RepRapFirmware for Duet 2 WiFi/Ethernet FIRMWARE_VERSION: 3.1.1 ELECTRONICS: Duet WiFi 1.02 or later FIRMWARE_DATE: 2020-05-19b2

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        • noisettetbouundefined
          noisettetbou @Phaedrux
          last edited by

          @Phaedrux
          And I've tryed M574 Y1 S4 and indicate some differents M915 H parameters but no change. Force on endstop or false detection.

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          • Phaedruxundefined
            Phaedrux Moderator
            last edited by

            Well what behaviour do you want when a stall is detected? stop both motors or stop each individually?

            https://duet3d.dozuki.com/Wiki/Gcode#Section_M574_RepRapFirmware_Num_3

            New endstop type S4 means use motor stall detection (like S3) but if there are multiple motors, stop each one individually as it stalls. S3 means use motor stall detection but as in RRF 2: stop all relevant motors when the first one stalls.

            What did you calculate for the H value?

            Can you send M98 P"config.g" in the gcode console and report the results?

            Z-Bot CoreXY Build | Thingiverse Profile

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            • noisettetbouundefined
              noisettetbou @Phaedrux
              last edited by noisettetbou

              @Phaedrux
              And I'm not sure of my calculation of the H parameter and speed. This is my Y motors (2 in series) of my Y axis specifications :
              Spécification électrique
              Numéro de pièce du fabricant: 17HS24-2104D
              Type de moteur: Bipolar Stepper
              Angle de pas: 1.8 deg
              Couple de maintien: 65Ncm(92.3oz.in)
              Courant/phase: 2.10A
              Tension: 3.360V
              Résistance/phase: 1.60ohms
              Inductance: 3.00mH ± 20%(1KHz)

              I've found more than 1000 mm/s. It's crazy !

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              • noisettetbouundefined
                noisettetbou @Phaedrux
                last edited by

                @Phaedrux said in Stall detection with 2 motors:

                Well what behaviour do you want when a stall is detected? stop both motors or stop each individually?

                I want to stop both motors. No choice, they're in series on the same driver.
                This is the results of my M98 P"config.g" :
                09/09/2020 à 22:16:49 M98 P"config.g"
                HTTP is enabled on port 80
                FTP is disabled
                TELNET is disabled
                Warning: Heater 0 appears to be over-powered. If left on at full power, its temperature is predicted to reach 365C
                Warning: Heater 0 appears to be over-powered. If left on at full power, its temperature is predicted to reach 269C

                Note my My PID aren't done for heaters errors.

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                • Phaedruxundefined
                  Phaedrux Moderator @noisettetbou
                  last edited by Phaedrux

                  @noisettetbou said in Stall detection with 2 motors:

                  I've found more than 1000 mm/s. It's crazy !

                  That seems wrong based on your motor specs. My calculation gives 145mm/s

                  b06c2710-6e30-4399-b172-89ab830a5ef1-image.png

                  Stall detection H value			
                  Hmin = full_steps_per_rev * rated_current * actual_current/(sqrt(2) * pi * rated_holding_torque)			
                  Full_steps_per_rev	200		
                  Rated_current (A)	2.100		
                  Actual_Current (A)	1.000		
                  Rated_holding_torque (Nm)	0.650		
                  Squareroot(2)	1.414		
                  Pi	3.142		
                  Hmin	145.436
                  

                  You may be able to reduce that speed further if you reduce the motor current further. You should try reducing it as much as possible such that you still have reliable movement. Right now you're using 50%, try 30%.

                  Z-Bot CoreXY Build | Thingiverse Profile

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                  • noisettetbouundefined
                    noisettetbou @Phaedrux
                    last edited by

                    @Phaedrux
                    Thanks for the calculation. I've confused the units of torque.

                    I've tried speeds up to 300 mm/s and differents current between 20 and 100% but nothing.

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                    • Phaedruxundefined
                      Phaedrux Moderator
                      last edited by

                      When you say the motors rotate in opposite directions, what do you mean?

                      Can you post a photo of the printer?

                      Z-Bot CoreXY Build | Thingiverse Profile

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                      • noisettetbouundefined
                        noisettetbou @Phaedrux
                        last edited by noisettetbou

                        @Phaedrux
                        That's a link to a photo of Y axis :
                        https://photos.app.goo.gl/oeFLBnE1iaKtcJMNA
                        The motors are biaxials and synchonysed by a shaft

                        oliofundefined 1 Reply Last reply Reply Quote 0
                        • oliofundefined
                          oliof @noisettetbou
                          last edited by oliof

                          @noisettetbou possibly crazy talk but could you disable one stepper for homing only? As they're synchronized by a shaft you should be able to live with that.

                          <>RatRig V-Minion Fly Super5Pro RRF<> V-Core 3.1 IDEX k*****r <> RatRig V-Minion SKR 2 Marlin<>

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                          • noisettetbouundefined
                            noisettetbou @oliof
                            last edited by

                            @oliof
                            It's a good idea. I've tried and it is the same problem.
                            So 2 motors on same driver and the series wiring aren't the source of the problem.
                            I'm trying to invert drivers.

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                            • noisettetbouundefined
                              noisettetbou @noisettetbou
                              last edited by

                              I've tried to invert driver with X and always the problem. As if my Y motors aren't compatibles with the stall detection.
                              Is it possible ? Crazy, no ?

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                              • oliofundefined
                                oliof
                                last edited by

                                Oh two steppers on a single driver? I can see how that will be bothersome/impossible. Maybe if you drive each motor independently ...

                                <>RatRig V-Minion Fly Super5Pro RRF<> V-Core 3.1 IDEX k*****r <> RatRig V-Minion SKR 2 Marlin<>

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                                • noisettetbouundefined
                                  noisettetbou @oliof
                                  last edited by

                                  @oliof
                                  It's no a problem if current is respected. I use two motors on same driver in X axis and no problem. And I done as you said for trying, so there is only one motor right now, and no good stall detection...

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                                  • Phaedruxundefined
                                    Phaedrux Moderator
                                    last edited by

                                    I think an endstop switch might be in your future.

                                    Z-Bot CoreXY Build | Thingiverse Profile

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                                    • noisettetbouundefined
                                      noisettetbou @Phaedrux
                                      last edited by

                                      @Phaedrux
                                      I think too... 😢 but I would like to understand

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                                      • dc42undefined
                                        dc42 administrators
                                        last edited by

                                        Have you used the motor EMF calculator at reprapfirmware.org to verify that you have enough VIN voltage to drive 2 motors in series without loss of torque?

                                        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

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                                        • oliofundefined
                                          oliof
                                          last edited by

                                          Difference between X and Y is often that Y moves more mass and there for needs better tuning. But I agree that an endstop likely will give you reliable results faster.

                                          <>RatRig V-Minion Fly Super5Pro RRF<> V-Core 3.1 IDEX k*****r <> RatRig V-Minion SKR 2 Marlin<>

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                                          • noisettetbouundefined
                                            noisettetbou @dc42
                                            last edited by

                                            @dc42 @Phaedrux @oliof
                                            dc42 has reason. My voltage is enough for each axis but limit for all axis in the same time.
                                            So i've decided to installing a Duex5.

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