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    SSR stuck on???

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    Duet Hardware and wiring
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    • gnydickundefined
      gnydick
      last edited by

      I just built my RailCore II ZLT kit and the bed turns on and stays on. The red light on the SSR is on as well. If I disconnect the positive from the SSR it turns off.

      What I don't understand is, I'd assume the duet is not sending any signal with the bed off, so what would trigger the SSR to switch?

      It's all wired correctly.

      dc42undefined 1 Reply Last reply Reply Quote 0
      • A Former User?
        A Former User
        last edited by

        As usual we'll take your word for everything being correct. That leaves the SSR to be faulty and the common failure mode is always on.

        If you wan't someone to review the rest you'll need to add some pictures and configs.

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        • DocTruckerundefined
          DocTrucker
          last edited by

          Some one recently accidentally inverted the heater control in the config leaving the heater to be on, when duet thought it was off.

          Other things to check is if there is signal going to the ssr board calling for heat. If you can disconnect the signal wires and there is still heat on the bed double check you haven't inverted the polarity by mistake if it's a DC bed. The body diodes on the mosfets will conduct in reverse polarity.

          Finally, adding a PS_ON triggered mechanical relay to isolate power to your heaters can really safe you some significant nastyness in combination with a maximum temp gcode setting.

          Running 3 P3Steel with Duet 2. Duet 3 on the shelf looking for a suitable machine. One first generation Duet in a Logo/Turtle style robot!

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

            @gnydick said in SSR stuck on???:

            It's all wired correctly.

            How exactly have you wires the SSR to the Duet? Photo please.

            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

            gnydickundefined 1 Reply Last reply Reply Quote 0
            • gnydickundefined
              gnydick @dc42
              last edited by

              @dc42 IMG_20191230_104512.jpg

              #1 to black wago
              #2 to bed loop eventually to white wago
              #3 bed pos
              #4 bed neg

              Behavior

              • Connected as is: bed turns on and stays on with heater off or on
              • #3 disconnected: bed stays off with heater off or on
              • #3 & #4 reversed: bed stays off with heater off or on
              1 Reply Last reply Reply Quote 0
              • gnydickundefined
                gnydick @DocTrucker
                last edited by

                @DocTrucker as soon as I disconnect the signal wires, the bed turns off.

                With them connected, the bed is always on, even if I turn the heater on, which would turn it off if my config was inverted, if I understand that correctly.

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                • Phaedruxundefined
                  Phaedrux Moderator
                  last edited by

                  Can you pull the SD card entirely, disconnect the bed connector on the Duet, power on, and carefully check if there is VIN across the bed terminals?

                  If yes, then that would indicate that the bed heater mosfet has failed on.

                  If not, Insert the SD card and check again, if there is now VIN across the terminals, then that would indicate a configuration issue.

                  Z-Bot CoreXY Build | Thingiverse Profile

                  gnydickundefined 1 Reply Last reply Reply Quote 0
                  • gnydickundefined
                    gnydick @Phaedrux
                    last edited by

                    @Phaedrux do I just set my meter to low voltage and touch to both terminals directly?

                    Phaedruxundefined 1 Reply Last reply Reply Quote 0
                    • Phaedruxundefined
                      Phaedrux Moderator @gnydick
                      last edited by

                      @gnydick I'm not familiar with your particular meter, but yes you'd set it to DC voltage in the range that would register 24v accurately. Touch + to + and - to -. Careful not to short anything else.

                      Z-Bot CoreXY Build | Thingiverse Profile

                      gnydickundefined 2 Replies Last reply Reply Quote 0
                      • gnydickundefined
                        gnydick @Phaedrux
                        last edited by

                        @Phaedrux yep, 24.1v 😞

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                        • gnydickundefined
                          gnydick @Phaedrux
                          last edited by

                          @Phaedrux can I use a different connection to trigger the SSR while I wait for the replacement?

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                          • A Former User?
                            A Former User
                            last edited by A Former User

                            If its not covered by warranty and you want to use the SSR anyway you might get away with soldering a wire from the gate on the bed FET and run that to the SSR input. (you may have to invert the output if you do)

                            Edit: sure, can def use any of the fan outputs instead.

                            gnydickundefined 1 Reply Last reply Reply Quote 0
                            • gnydickundefined
                              gnydick @A Former User
                              last edited by

                              @bearer any pointers on how to set that up? Would I just wire two of the pwm pins to the SSR and map the bed heater to that pwm?

                              A Former User? 1 Reply Last reply Reply Quote 0
                              • Phaedruxundefined
                                Phaedrux Moderator
                                last edited by

                                Since the bed heater is being powered via SSR and the SSR input will accept lower voltage than VIN, you could use any other open heater or fan output with a little configuration.

                                If the Duet came with the RailCore kit I'd seek a warranty claim.

                                Z-Bot CoreXY Build | Thingiverse Profile

                                gnydickundefined 1 Reply Last reply Reply Quote 0
                                • A Former User?
                                  A Former User @gnydick
                                  last edited by

                                  @gnydick said in SSR stuck on???:

                                  @bearer any pointers on how to set that up? Would I just wire two of the pwm pins to the SSR and map the bed heater to that pwm?

                                  i'd use the "ground" from a fan, that ground is pwm controlled by the duet and you can use any supply voltage, the one on the fan output is convenient though. then unmap the fan if needed and map the heater. I'm sure some of the wizzards can help with the config if needed

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                                  • gnydickundefined
                                    gnydick @Phaedrux
                                    last edited by

                                    @Phaedrux I am, but it will take time. I'd like to get everything else tested out while I wait.

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

                                      You can also use a spare heater output on the Duet or the DueX5.

                                      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

                                      gnydickundefined 1 Reply Last reply Reply Quote 0
                                      • Phaedruxundefined
                                        Phaedrux Moderator
                                        last edited by

                                        Here's the directions for using a chamber heater. It's the same principal. Using an alternate pin for controlling an extra heater. The only difference for you is that instead of defining a new heater 3, you'd be altering the configuration for heater 0 (the bed on duet 2)

                                        https://duet3d.dozuki.com/Wiki/Connecting_and_configuring_a_chamber_heater

                                        Z-Bot CoreXY Build | Thingiverse Profile

                                        gnydickundefined 1 Reply Last reply Reply Quote 0
                                        • gnydickundefined
                                          gnydick @Phaedrux
                                          last edited by

                                          @Phaedrux thanks

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

                                            It is highly unlikely that the SSR has failed since it is not stuck in the 'on' position. It is way more likely that there is a wiring error.
                                            Are you aware that the positive line will always be high no matter if the heater is on or off?
                                            Simply wiring the negative to ground will cause all these issues.
                                            Verify the ruting of the two control lines.

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