Expansion Header and Chamber Heater SSR
I am setting up my chamber heater and everything seems fine except I cannot get the SSR to turn on. I am using a Fotek SSR-25DA I can connect the device to +3.3 (pin3) and Gnd (pin2) and it turns on fine and the heater gets hot. When + terminal on SSR is connected to +3.3 (pin3) and SSR - terminal connected to Heater 7 (pin31). There seems to be no joy. The chamber temp sensor seems to be working fine.
Here is the code in the config file:
; Chamber Heater
M141 H7 ; heater 7 is the chamber heater
M305 P7 R4700 T100000 B3950 ; heater 7 is monitored by a 100K thermistor with B=3950 and a 4.7K series resistor
M301 H7 P-1 ; use bang-bang control for the chamber heater
Through the web interface M141 S55 to set the temp, the Chamber says "active", but no output comes on.
Assuming you are not using very old firmware, you should use M307 H7 B1 to select bang-bang control, not M301 H7 P-1.
Ok, I made that change, but still no luck getting the SSR to turn on
Sabagmn last edited by
I may be quite wrong here, but would heater 7 not be H6 in the config since numbering of the heaters starts at H0?
Whoops. The heat came on, but no light on the SSR. It faulted out after only a couple seconds being active. I'll need to run the tuning once I get the covers on the machine, but it looks like it's working.
Thanks for the help.
Glad it's working. You may need to configure a large dead time using M307 to get the tuning to work without faulting, depending on where the thermistor is in relation to the heater.