Extruder PWM

I am running my printer on a Mega/RAMPS. Currently I have my power supply set at 12V but I am finding that at high speeds the steppers are sometimes skipping. I want to set my power supply voltage higher (maybe 24V) but in order to avoid burning out the extruder heater I want to set the heater PWM to 50%. What setting in the config will allow me to do that? Is it the PDM_FOR_EXTRUDER? EXT0_PID_INTEGRAL_DRIVE_MAX? EXT0_PID_MAX?


  • No, you want it to limit to 25%. Voltage is sqared in power term so double voltage = 4 x power. You should reduce these

    /** \brief lower value for integral part
    The I state should converge to the exact heater output needed for the target temperature.
    To prevent a long deviation from the target zone, this value limits the lower value.
    A good start is 30 lower then the optimal value. You need to leave room for cooling.
     Overridden if EEPROM activated.
    /** P-gain.  Overridden if EEPROM activated. */
    #define EXT0_PID_PGAIN_OR_DEAD_TIME   24
    /** I-gain. Overridden if EEPROM activated.
    #define EXT0_PID_I   0.88
    /** Dgain.  Overridden if EEPROM activated.*/
    #define EXT0_PID_D 80
    // maximum time the heater is can be switched on. Max = 255.  Overridden if EEPROM activated.
    #define EXT0_PID_MAX 255

    And do not forget the heated bed and fans as well. Hope it works well as it still puts 24V into it just not all the time so it avereges to less.
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