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    Turn on a fan automatically when a heater is activated?

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    • pro3dundefined
      pro3d @fcwilt
      last edited by

      @fcwilt said in Turn on a fan automatically when a heater is activated?:

      @pro3d

      Does it have to come on immediately or could it be tied to temperature?

      You could have a temp sensor placed where appropriate and set up the fan to be tied to a threshold temp, like you would with a extruder fan.

      Frederick

      It has to come immediately yes. As the Temp sensor is in the box, not on the heater

      Valkyrie DIY High Temp 3D Printer

      R&D - Engineering Designer - Viking 3D Printers
      https://vkingprinter.com/

      fcwiltundefined 1 Reply Last reply Reply Quote 0
      • fcwiltundefined
        fcwilt @pro3d
        last edited by

        @pro3d

        I was thinking of putting the temp sensor in the box.

        So what bad things would happen if it didn't come on until the temp sensor read some threshold temp?

        Thanks.

        Frederick

        Printers: a small Utilmaker style, a small CoreXY and a E3D MS/TC setup. Various hotends. Using Duet 3 hardware running 3.4.6

        pro3dundefined 1 Reply Last reply Reply Quote 0
        • pro3dundefined
          pro3d @fcwilt
          last edited by

          @fcwilt said in Turn on a fan automatically when a heater is activated?:

          @pro3d

          I was thinking of putting the temp sensor in the box.

          So what bad things would happen if it didn't come on until the temp sensor read some threshold temp?

          Thanks.

          Frederick

          The sensor will not read more than ambient for a while and the heater will go wild and the fan shroud will creep/melt

          Valkyrie DIY High Temp 3D Printer

          R&D - Engineering Designer - Viking 3D Printers
          https://vkingprinter.com/

          fcwiltundefined 1 Reply Last reply Reply Quote 0
          • fcwiltundefined
            fcwilt @pro3d
            last edited by

            @pro3d

            Well if you put the sensor where the heat is an issue and set the threshold to 30 it should turn on quite soon after the heat turns on.

            Frederick

            Printers: a small Utilmaker style, a small CoreXY and a E3D MS/TC setup. Various hotends. Using Duet 3 hardware running 3.4.6

            pro3dundefined 1 Reply Last reply Reply Quote 0
            • jens55undefined
              jens55
              last edited by

              I have a similar issue that is still waiting for me to implement a solution. What I will be doing is to set up a time delay relay of some kind. Either a commercial relay or a standard relay with a simple 555 timer circuit (ie home-brew).
              The fan turns on with the heater. The heater turning on sets/activates a relay that also provides power to the fan (so the fan is powered by the heater as well as through this relay). When the heater turns off, a timer starts while the secondary relay stays activated (and thus provides power to the fan). After a given time period (say 30 seconds) the timer drops out, the secondary relay releases and the cooling fan has no more power and stops.
              Depending on how the fan is powered (high side switched or low side switched), the relay might be in the high side circuit or the low side circuit.
              I have not yet looked to see if an off-the-shelf time delay relay can be had for cheap or if I should implement the timer function myself .... I would expect a commercial solution would be available from AliExpress at a reasonable cost.

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              • pro3dundefined
                pro3d @fcwilt
                last edited by

                @fcwilt said in Turn on a fan automatically when a heater is activated?:

                @pro3d

                Well if you put the sensor where the heat is an issue and set the threshold to 30 it should turn on quite soon after the heat turns on.

                Frederick

                This would not report box temp as being close to the heater temperature would be higher than chamber temp

                Valkyrie DIY High Temp 3D Printer

                R&D - Engineering Designer - Viking 3D Printers
                https://vkingprinter.com/

                fcwiltundefined 1 Reply Last reply Reply Quote 0
                • fcwiltundefined
                  fcwilt @pro3d
                  last edited by

                  @pro3d said in Turn on a fan automatically when a heater is activated?:

                  This would not report box temp as being close to the heater temperature would be higher than chamber temp

                  I've gotten confused.

                  I thought the goal was to turn on the fan to protect the fan shroud.

                  So if the sensor is near the shroud would it not serve to protect the shroud by turning on the fan before the temp was high enough to be a problem?

                  Frederick

                  Printers: a small Utilmaker style, a small CoreXY and a E3D MS/TC setup. Various hotends. Using Duet 3 hardware running 3.4.6

                  pro3dundefined 1 Reply Last reply Reply Quote 0
                  • pro3dundefined
                    pro3d @fcwilt
                    last edited by

                    @fcwilt said in Turn on a fan automatically when a heater is activated?:

                    @pro3d said in Turn on a fan automatically when a heater is activated?:

                    This would not report box temp as being close to the heater temperature would be higher than chamber temp

                    I've gotten confused.

                    I thought the goal was to turn on the fan to protect the fan shroud.

                    So if the sensor is near the shroud would it not serve to protect the shroud by turning on the fan before the temp was high enough to be a problem?

                    Frederick

                    Yes but the sensor is supposed to monitor the chamber/box temp. Not the heater temperature, so the sensor need to be away from the heater....

                    Valkyrie DIY High Temp 3D Printer

                    R&D - Engineering Designer - Viking 3D Printers
                    https://vkingprinter.com/

                    engikeneerundefined 1 Reply Last reply Reply Quote 0
                    • engikeneerundefined
                      engikeneer @pro3d
                      last edited by

                      @pro3d he's meaning add a second sensor. The advantage of this method is that you actively know if the shroud is getting too hot, and you could even set up over temperature warning if it still got too hot with the fan on (or the fan fails!). It also gives you the delayed turn off in on, as itll stay on til the heater has cooled (which may be differentlengths depending on how longs its been on). To me, this is the 'safe' way to monitor this issue, though generally I prefer to avoid designing in potential thermal runaway events where possible.

                      The Daemon.g option is the firmware only approach you want. It is a script that repeatedly runs in the background, so you can use metacommands (I.e. the RRF built in programming language) to put whatever if/else/while/whatever blocks in to control your fan based off accessing machine data in the object model. You'll need to be on RRF3 and do some reading up on the meta commands which is all on the wiki.

                      E3D TC with D3Mini and Toolboards.
                      Home-built CoreXY, Duet Wifi, Chimera direct drive, 2x BMG, 300x300x300 build volume
                      i3 clone with a bunch of mods

                      1 Reply Last reply Reply Quote 3
                      • pro3dundefined
                        pro3d
                        last edited by

                        @moth4017 managed to get this sorted out with the daemon.g file and some if, elif commands

                        Now the fan activate when heater turns on, and off when temp is below 35c

                        Valkyrie DIY High Temp 3D Printer

                        R&D - Engineering Designer - Viking 3D Printers
                        https://vkingprinter.com/

                        Exerqtorundefined 1 Reply Last reply Reply Quote 1
                        • Exerqtorundefined
                          Exerqtor @pro3d
                          last edited by

                          @pro3d Totally beside the point and off subject, but what heater is it you're using?

                          1 Reply Last reply Reply Quote 0
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