Chamber Heat and Cooling from the same setpoint?
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I have a machine with a Duet3 CH6 board.
I will be adding a heater in the enclosure. My machines live in the garage so ambient can be pretty cool in winter, and toasty in the summer.
I am rigging up an external 110VAC blower draw air from the top of the heated chamber when the temperature exceeds the set point by more than maybe 2 degrees.I have the chamber heater configured. Don't know if I've done everything right yet as I don't have the heaters in hand. I know how to set fans to be thermostatically controlled, but I don't know how to reference the chamber temp for that.
The chamber heater will be controlled by an SSR connected to OUT2.
The exhaust fan for the chamber will be on an SSR off of OUT3.Is it possible to have the setpoint for the chamber temperature also be the setpoint for the exhaust blower, plus an offset value? Chamber temp at 60C. If it reaches 62C, turn on the blower. If chamber temp is set to 45C, exhaust blower starts at 47C.
Thanks!
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If you already have a chamber temp sensor setup to control the heater I think you can use it for the thermostatic fan control without issue. Just define the fan with M106 and reference the chamber temp for the thermostatic control.
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@Phaedrux Thanks. I haven't played with variables in GCODE yet. Could you post a simple example of interrogating the chamber temp value and using that in a subsequent command?
Feels like that would be a start-script thing and not a live relationship between the cooling and the chamber temp. IOW, if I change the chamber temp manually during a print, the cooling temp would not be updated automatically - I'd need to re-run the commands to read the chamber temp and write that to the cooling set point. That's OK - just wanting to understand things.
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No variables needed. Just a M106 command to setup the fan as thermostatic. Just like the hotend or chamber heater fan you already have.
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@Phaedrux Maybe I'm missing something ...
The existing fans with thermostatic control are at a set temperature using the T parameter.If I set the chamber temperature to 60C on the DWC page, I need the chamber cooling fan to be set at 62C. If I set the chamber temp to 30C, the cooling fan needs to trigger at 32C.
So for the M106 command, I need to read the chamber temperature setting, add an offset value, and make that the set point for the thermostatic control.
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@zemlin - It will be something like the following where P1 is the value for your exhaust fan and heaters[3] is the value of your chamber heater. One caveat is you will have to run this command each time the chamber temp is modified with the stock firmware.
M106 P1 T{heat.heaters[3].active + 2} H1 -
@zemlin Ah sorry, I misunderstood your request.
oozebot has your answer though.
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@oozeBot - Thank you!
