Thermostatically Controlled Fan by Sensor# not Heater??

2K3M

Using RRFW 3.3

I am trying to configure a fan so that it is thermostatically controlled by a sensor that is associated with but not directly assigned to a heating element and having some trouble figuring how to go about this.

I have a large chamber with a powerful heating element where the surface of the heating element gets much hotter than actual chamber temps, that is until the chamber temps can rise and even out to set temps. In order to spread the heat from the element i have a blower fan mounted to the heating element. A soon as the heating element gets a little over 28-30c the fan needs to also kick on and remain on until surface temp of heating element drops back below 28-30c.

I have 2 thermistors associated with this chamber heater...one is actual surface temperature of the heating element itself and the other is to monitor actual air temps in the chamber, which at startup can vary drastically like nearly 180c difference. I currently have the heater configured in M950 to use the air temp probing thermistor as i want to maintain chamber air temps accurately....so surface temps initially get much much hotter than chamber temps...instead of just having the blower fan on at all times i want to configure it to be thermostatically controlled by the sensor mounted to the chamber heaters surface which is not the sensor assigned to this heater...and thermostatically controlled configuration requires a heater # to control.....I have attempted to just configure the fan using Chamber Heater w/ Air probing thermistor but seeing as the fan doesn't kick on to spread the heated air until the chamber temps reach specified temps the actual heating element itself gets to something like 200-220c before the fan kicks on to spread heated air throughout the chamber.

Should i be looking into setting up virtual heaters? Or a virtual tool? Or conditional g-code?

Phaedrux

Show us your config.g with what you have now.

2K3M

@phaedrux

if you want me to post the entire thing i can....but this is what i have with what pertains to the chamber heater.

;Chamber
M308 S3 P"temp2" Y"thermistor" A"Chamber_Air_Temp" T100000 B3799 H0 L0 ;chamber air temp
M950 H3 C"0.out2" T3 ;Chamber Heater
M307 H3 B0 R0.157 C326.5 D11.10 S1.00 V0 ;Chamber Heater Configuration
M141 H3 ;Define Chamber Heater
M143 H3 S135 ;Set max CHAMBER temperature

;Other Thermistors/Sensor
M308 S5 P"0.temp3" Y"thermistor" A"Chamber_Heater_Surface_Temp" T100000 B4240 H0 L0

; Fans
M950 F4 C"0.out7" ;Chamber Fan on "out7" connector
M106 P4 S255 H3 T30 C"Chamber_Fan" ;Chamber Fan enable thermostatic mode for chamber heater

Phaedrux

@2k3m said in Thermostatically Controlled Fan by Sensor# not Heater??:

post the entire thing

yes please. gives me a better idea of all that's going on.

You should be able to create a thermostatic fan that runs based on the thermistor. I'll get back to you after I've had some sleep.

dc42

@2k3m yes you can do that. Just change H3 to H5 in your M106 command. In RRF3 the H parameter in M106 is a sensor number, not a heater number as it was in RRF2.

2K3M

@dc42 @Phaedrux

Changing M106 H3 to H5 did work! Wow thank you both so much for the help! You guys at Duet are awesome! Have a great weekend!