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    Problem with Magnetic Sensor

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    Filament Monitor
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    • dc42undefined
      dc42 administrators @DarylMcM
      last edited by dc42

      @DarylMcM said in Problem with Magnetic Sensor:

      Note the agc has climbed to 70 while the mag has continued to fluctuate from 130 to 132. AGC usually stands for automatic gain control and my assumption of the mag number has to do with magnetic strength, but I'm just guessing.

      That's correct. The 'mag' value is after agc is applied, so will always be around the same value until the gain runs out (indicated by agc=128 which is its maximum value). So it is the agc value that gives a better indication of magnetic field strength, lower values = higher strength.

      To get good readings, it is critical that when the extruder retracts filament, the filament gets pushed back through the filament monitor and turns it backwards. This is best achieved by keeping the filament path between the filament monitor and extruder drive very short and straight, and constraining the filament in that region in PTFE tubing which is only just large enough for the filament,

      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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      • DarylMcMundefined
        DarylMcM
        last edited by

        dc42, I do have a minimal distance between the monitor and the extruder entrance. About 3mm. I do not have PTFE in that small area. I do have PTFE restraining the filament from the reel to the entrance of the monitor keeping it straight.
        Does the 'A' parameter of the M591 entry need to be set in order for the retractions to be Taken into account?

        dc42undefined 1 Reply Last reply Reply Quote 0
        • dc42undefined
          dc42 administrators @DarylMcM
          last edited by

          @DarylMcM said in Problem with Magnetic Sensor:

          Does the 'A' parameter of the M591 entry need to be set in order for the retractions to be Taken into account?

          No. The default is A0 which means that actual/commanded movement will only be compared during normal printing moves, not retraction or re-prime moves. You can try A1 if you like, but it will probably give worse results.

          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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          • RandyLundefined
            RandyL
            last edited by

            I seem to be having a simmer issue. I installed the mag sensor about a week ago recently purchased from Filastruder as well. It was working okfor a couple of prints then all of a sudden it started overrunning the set parameters of R60:130 L24.8 E3.0. When I swapped out the filament to Ninja Flex ( a very soft TPU) I stated seeing under runs of ~ 30 to 35%. I adjusted the "R" value accordingly and the remainder of the TPU prints finished off ok. I then swapped out my .04 nozzle for a .8mm nozzle with PLA+ and things went south. I'm now seeing under runs down to 10% and over runs up to 330% My last print was like so:

            Duet3D rotating magnet filament monitor v2 on input 3, enabled, sensitivity 25.05mm/rev, allow 10% to 370%, check every 3.0mm, current pos 259.8, measured sensitivity 25.27mm/rev, min 94% max 179% over 9348.6mm

            I replaced the the cable between the sensor the E1 stop input with a twister trio to cancel out any interference but this did not make any difference.

            My diag output:

            === Diagnostics ===
            RepRapFirmware for Duet 2 WiFi/Ethernet version 2.03 running on Duet WiFi 1.02 or later
            Board ID: 08DGM-917DA-G4MSJ-6JTF0-3S86M-T9NMA
            Used output buffers: 1 of 24 (12 max)
            === RTOS ===
            Static ram: 25680
            Dynamic ram: 94232 of which 16 recycled
            Exception stack ram used: 540
            Never used ram: 10604
            Tasks: NETWORK(ready,524) HEAT(blocked,1236) MAIN(running,1668) IDLE(ready,160)
            Owned mutexes:
            === Platform ===
            Last reset 01:22:56 ago, cause: software
            Last software reset at 2019-11-18 13:58, reason: User, spinning module GCodes, available RAM 10652 bytes (slot 1)
            Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x0441f000 BFAR 0xe000ed38 SP 0xffffffff Task 0x4e49414d
            Error status: 0
            Free file entries: 10
            SD card 0 detected, interface speed: 20.0MBytes/sec
            SD card longest block write time: 12.1ms, max retries 0
            MCU temperature: min 28.5, current 29.3, max 31.9
            Supply voltage: min 23.9, current 24.3, max 24.6, under voltage events: 0, over voltage events: 0, power good: yes
            Driver 0: standstill, SG min/max 0/1023
            Driver 1: standstill, SG min/max 0/1023
            Driver 2: standstill, SG min/max 0/117
            Driver 3: standstill, SG min/max 0/1023
            Driver 4: standstill, SG min/max 0/107
            Date/time: 2019-11-18 15:21:31
            Cache data hit count 4294967295
            Slowest loop: 59.42ms; fastest: 0.07ms
            I2C nak errors 0, send timeouts 0, receive timeouts 0, finishTimeouts 0, resets 0
            === Move ===
            Hiccups: 0, FreeDm: 169, MinFreeDm: 121, MaxWait: 1366776ms
            Bed compensation in use: mesh, comp offset 0.373
            === DDARing ===
            Scheduled moves: 0, completed moves: 0, StepErrors: 0, LaErrors: 0, Underruns: 0, 0
            === Heat ===
            Bed heaters = 0 -1 -1 -1, chamberHeaters = -1 -1
            Heater 0 is on, I-accum = 0.1
            Heater 1 is on, I-accum = 0.6
            === GCodes ===
            Segments left: 0
            Stack records: 3 allocated, 0 in use
            Movement lock held by null
            http is idle in state(s) 0
            telnet is idle in state(s) 0
            file is idle in state(s) 0
            serial is idle in state(s) 0
            aux is idle in state(s) 0
            daemon is idle in state(s) 0
            queue is idle in state(s) 0
            autopause is idle in state(s) 0
            Code queue is empty.
            === Network ===
            Slowest loop: 25.93ms; fastest: 0.00ms
            Responder states: HTTP(0) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0) Telnet(0)
            HTTP sessions: 1 of 8

            • WiFi -
              Network state is running
              WiFi module is connected to access point
              Failed messages: pending 0, notready 0, noresp 0
              WiFi firmware version 1.23
              WiFi MAC address ec:fa:bc:01:e0:39
              WiFi Vcc 3.32, reset reason Turned on by main processor
              WiFi flash size 4194304, free heap 25464
              WiFi IP address 192.168.1.19
              WiFi signal strength -53dBm, reconnections 0, sleep mode modem
              Socket states: 0 0 0 0 0 0 0 0
              === Filament sensors ===
              Extruder 0: pos 250.31, ok, measured sens 25.28mm/rev min 94% max 179% over 10057.0mm, errs: frame 0 parity 0 ovrun 0 pol 0 ovdue 0
              3:06:28 PMFinished printing file 0:/gcodes/rEX.gcode, print time was 0h 46m
            dc42undefined 1 Reply Last reply Reply Quote 0
            • ciaossuundefined
              ciaossu
              last edited by

              I just purchased a filament sensor from Filastruder and set it up. My mount is not ideal according to the directions because I do not want to mount the sensor on top of the bondtech extruder that is set up as a direct drive on a Railcore. This would add a lot of moving weight. So the sensor is mounted outside the printer and there is a long ptfe tube between the sensor output and the bondtech. I was able to run 3-4 12 hour prints without issue. Now though the sensor stops and says not enough movement was detected.

              Is there a way to configure the sensor to simply detect any movement over x amount of time and not try to exactly sync the movements to the print? Should I be using the switch and the magnet sensor? I tried opening up the tolerance to work over a wide range but that did not help.

              Settings:
              Duet3D magnetic filament monitor on input 3, enabled, sensitivity 24.70mm/rev, allow 20% to 250%, check every 3.0mm, version 2, measured sensitivity 24.82mm/rev, min 91% max 105% over 160.8mm

              If you need additional information please let me know.

              dc42undefined 1 Reply Last reply Reply Quote 0
              • dc42undefined
                dc42 administrators @RandyL
                last edited by dc42

                @RandyL said in Problem with Magnetic Sensor:

                I then swapped out my .04 nozzle for a .8mm nozzle with PLA+ and things went south. I'm now seeing under runs down to 10% and over runs up to 330% My last print was like so:
                Duet3D rotating magnet filament monitor v2 on input 3, enabled, sensitivity 25.05mm/rev, allow 10% to 370%, check every 3.0mm, current pos 259.8, measured sensitivity 25.27mm/rev, min 94% max 179% over 9348.6mm

                1. How close to the extruder drive inlet is the filament monitor? It needs to be very close, especially for soft filaments such as TPU. Otherwise, when the extruder retracts filament, the filament will try to bunch up in the space between the extruder inlet and the filament monitor, instead of retracting through the filament monitor.

                2. A 0.8mm nozzle has four times the filament flow of a 0.4mm nozzle. To get comparable performance from the filament monitor, you should increase the measurement length in proportion. So try 12mm instead of 3mm.

                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
                • dc42undefined
                  dc42 administrators @ciaossu
                  last edited by

                  @ciaossu said in Problem with Magnetic Sensor:

                  I just purchased a filament sensor from Filastruder and set it up. My mount is not ideal according to the directions because I do not want to mount the sensor on top of the bondtech extruder that is set up as a direct drive on a Railcore. This would add a lot of moving weight. So the sensor is mounted outside the printer and there is a long ptfe tube between the sensor output and the bondtech.

                  That is not going to work well, because filament will bunch up in the tube when retraction occurs..

                  Is there a way to configure the sensor to simply detect any movement over x amount of time and not try to exactly sync the movements to the print? Should I be using the switch and the magnet sensor? I tried opening up the tolerance to work over a wide range but that did not help.

                  You still have the measurement distance set to 3.0mm. Try a larger amount.

                  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

                  RandyLundefined 1 Reply Last reply Reply Quote 0
                  • tagliaundefined
                    taglia
                    last edited by

                    Hi, a quick update from me. Duet replaced my sensor (kudos to @Roland, the swap was quick and flawless, even if I live in Singapore).

                    I have been using the new sensor for several weeks now, and it has saved many prints, and potentially more disastrous situations. The sensor never paused the printer without a valid reason: clogged nozzle, empty spool, and once the spool even fell to the floor.

                    Great tool, highly recommended.

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                    • T3P3Tonyundefined
                      T3P3Tony administrators
                      last edited by

                      @taglia thanks for the update

                      www.duet3d.com

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                      • RandyLundefined
                        RandyL @dc42
                        last edited by

                        @dc42,

                        Thanks for the advice. I will try increasing the measurement length as you suggest. My sensor is mounted ~20mm above a direct drive extruder and was flexing around a lot. I added a brace which helped a lot but am still having issue. I will try increasing the measurement length as you suggest.

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