No output for chamber heater



  • I'm probably screwing something up here but I'm trying to get a chamber heater to work on heater channel E2 on the Duex5. I have a PT100 daughter board plugged into the Duex5 and a PT100 4 wire sensor connected. I wired the input of an SSR to the E2 output on the Duex5, + to +, - to -. The SSR should switch on the AC to the heater/fan combo.

    I added this to the config.g

    M141 H2 ; heater 2 is the chamber heater
    M305 P2 S"CHAMBER" X204 ; heater 2 is monitored by a PT100 sensor on the first duex5 PT100 connector
    M307 H2 B1 ; use bang-bang control for the chamber heater

    At power on the web console does see the chamber heater and reports the correct temperature. I can hold the sensor and the temp will start to rise so the temp sensor is working.

    But when I then send an M141 S80 to it nothing happens, the SSR doesn't turn on and after a short time I get an error that it is not heating fast enough. What am I missing?



  • I just noticed I had the something plugged into the E2 PWM connector on the Duex so I moved to E6 heater and now it is working other than now I get the error about the temp not rising fast enough so I need to overcome that...



  • Hi,

    The numbering of things can get a bit confusing.

    The heater numbers on the Duet are 0,1,2. On the Duex5 they are 3,4,5,6,7.

    Frederick



  • @warpster said in No output for chamber heater:

    now it is working other than now I get the error about the temp not rising fast enough so I need to overcome that...

    see https://duet3d.dozuki.com/Wiki/Tuning_the_heater_temperature_control

    If auto tuning fails with a message that the temperature is not rising fast enough, this indicates that either you are using too low a P value in the M303 command, or the dead time in the existing model is much too low for your heater. You can increase the dead time using the M307 command. For example, sending M307 H0 D30 will increase the dead time to 30 seconds. The actual dead time will be known after a successful auto tuning.



  • I ran through PID tuning and that took care of the errors. The chamber heater is working as it should now. Takes about 30 Min to get to 60C by itself but with the bed heater it is much faster.


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