Method PID_autotune

Marlin/src/module/temperature.cpp:813–1066

* PID Autotuning (M303) * * Alternately heat and cool the nozzle, observing its behavior to * determine the best PID values to achieve a stable temperature. * Needs sufficient heater power to make some overshoot at target * temperature to succeed. */

   * temperature to succeed.
   */
  void Temperature::PID_autotune(const celsius_t target, const heater_id_t heater_id, const int8_t ncycles, const bool set_result/*=false*/) {
    celsius_float_t current_temp = 0.0;
    int cycles = 0;
    bool heating = true;

    millis_t next_temp_ms = millis(), t1 = next_temp_ms, t2 = next_temp_ms;
    long t_high = 0, t_low = 0;

    raw_pid_t tune_pid = { 0, 0, 0 };
    celsius_float_t maxT = 0, minT = 10000;

    const bool isbed = (heater_id == H_BED),
           ischamber = (heater_id == H_CHAMBER);

    #if ENABLED(PIDTEMPCHAMBER)
      #define C_TERN(T,A,B) ((T) ? (A) : (B))
    #else
      #define C_TERN(T,A,B) (B)
    #endif
    #if ENABLED(PIDTEMPBED)
      #define B_TERN(T,A,B) ((T) ? (A) : (B))
    #else
      #define B_TERN(T,A,B) (B)
    #endif
    #define GHV(C,B,H) C_TERN(ischamber, C, B_TERN(isbed, B, H))
    #define SHV(V) C_TERN(ischamber, temp_chamber.soft_pwm_amount = V, B_TERN(isbed, temp_bed.soft_pwm_amount = V, temp_hotend[heater_id].soft_pwm_amount = V))
    #define ONHEATINGSTART() C_TERN(ischamber, printerEventLEDs.onChamberHeatingStart(), B_TERN(isbed, printerEventLEDs.onBedHeatingStart(), printerEventLEDs.onHotendHeatingStart()))
    #define ONHEATING(S,C,T) C_TERN(ischamber, printerEventLEDs.onChamberHeating(S,C,T), B_TERN(isbed, printerEventLEDs.onBedHeating(S,C,T), printerEventLEDs.onHotendHeating(S,C,T)))

    #define WATCH_PID DISABLED(NO_WATCH_PID_TUNING) && (ALL(WATCH_CHAMBER, PIDTEMPCHAMBER) || ALL(WATCH_BED, PIDTEMPBED) || ALL(WATCH_HOTENDS, PIDTEMP))

    #if WATCH_PID
      #if ALL(THERMAL_PROTECTION_CHAMBER, PIDTEMPCHAMBER)
        #define C_GTV(T,A,B) ((T) ? (A) : (B))
      #else
        #define C_GTV(T,A,B) (B)
      #endif
      #if ALL(THERMAL_PROTECTION_BED, PIDTEMPBED)
        #define B_GTV(T,A,B) ((T) ? (A) : (B))
      #else
        #define B_GTV(T,A,B) (B)
      #endif
      #define GTV(C,B,H) C_GTV(ischamber, C, B_GTV(isbed, B, H))
      const uint16_t watch_temp_period = GTV(WATCH_CHAMBER_TEMP_PERIOD, WATCH_BED_TEMP_PERIOD, WATCH_TEMP_PERIOD);
      const uint8_t watch_temp_increase = GTV(WATCH_CHAMBER_TEMP_INCREASE, WATCH_BED_TEMP_INCREASE, WATCH_TEMP_INCREASE);
      const celsius_float_t watch_temp_target = celsius_float_t(target - (watch_temp_increase + GTV(TEMP_CHAMBER_HYSTERESIS, TEMP_BED_HYSTERESIS, TEMP_HYSTERESIS) + 1));
      millis_t temp_change_ms = next_temp_ms + SEC_TO_MS(watch_temp_period);
      celsius_float_t next_watch_temp = 0.0;
      bool heated = false;
    #endif

    TERN_(HAS_FAN_LOGIC, fan_update_ms = next_temp_ms + fan_update_interval_ms);

    TERN_(EXTENSIBLE_UI, ExtUI::onPIDTuning(ischamber ? ExtUI::pidresult_t::PID_CHAMBER_STARTED : isbed ? ExtUI::pidresult_t::PID_BED_STARTED : ExtUI::pidresult_t::PID_STARTED));

    if (target > GHV(CHAMBER_MAX_TARGET, BED_MAX_TARGET, hotend_max_target(heater_id))) {
      SERIAL_ECHOPGM(STR_PID_AUTOTUNE); SERIAL_ECHOLNPGM(STR_PID_TEMP_TOO_HIGH);
      TERN_(EXTENSIBLE_UI, ExtUI::onPIDTuning(ExtUI::pidresult_t::PID_TEMP_TOO_HIGH));