Temperature Control Fine Tuning

This page provides tips for fine-tuning temperature control settings in Smoothie.

Common Scenarios

Using a 12V Heater on a 24V System

If you are using a 12V heater on a 24V system, you need to limit the PWM duty cycle to prevent damage.

You need to set max_pwm to 64:

temperature_control.hotend.max_pwm 64

Fixing Temperature Overshoot (10°C or More)

If you are getting 10°C or more initial overshoot of temperature, you can set i_max to a lower value (default is max_pwm).

128 seems to be a good value, but it can be tuned with M301 S0 Xnnn where nnn is a number less than or equal to max_pwm:

temperature_control.hotend.i_max 128

Setting Maximum Safe Temperature

To avoid accidental setting of too high a temperature, you can set max_temp to the maximum temp that is safe for the target heater.

This will ignore any setting of temperatures that are higher than this and instead set the temp to max_temp.

It will also trigger a shutdown if this temperature is exceeded.

temperature_control.hotend.max_temp 230

For more information on temperature control, see: