M307 S does not work

Frederik561 · 27 Nov 2020, 10:46

Hello

I have a problem using the M307 S command. I am using a peltier module to cool down the bed and it works fine when S1 is used. However, if I use for example S0.5, the heater (cooler) is just turned on at all times. Any idea why that is?

Thanks in advance
/Frederik

Veti · 27 Nov 2020, 11:21

disable Bang Bang to enable PWM.

B0 instead of B1

Veti · 27 Nov 2020, 11:22

also your thermistor setting is wrong. B4138 is the default. Look up the correct value in your thermistor documentation.

dc42 · 27 Nov 2020, 14:10

Peltier modules behave very poorly with PWM, unless you smooth the output of the PWM using a diode, inductor and capacitor.