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/** \file
\brief Manage heaters, including PID and PWM.
Code for heater_init() and heater_set() is in the platform dependant include
file and should pass six test cases when operating the heater via M106, temp
sensors disabled:
- PWM used on PWM-able pin, not inverted.
- PWM pin used as on/off pin, not inverted.
- Non-PWM-able pin, not inverted.
- The three above, but inverted.
In each test it should pass these tests:
- Heater full on with M106 S255.
- Heater full off with M106 S0.
- Heater 10% on with M106 S25 on PWM pins.
- Heater full off after reset, power supply turned on by other means.
- For testing the inverted cases it's OK to check for behaving the opposite
of the M106 command.
*/
#include "heater.h"
#define TEACUP_C_INCLUDE
#include "heater-avr.c"
#include "heater-arm.c"
#undef TEACUP_C_INCLUDE
#include <stdlib.h>
#include "arduino.h"
#include "debug.h"
#include "crc.h"
#ifndef EXTRUDER
#include "sersendf.h"
#endif
#ifdef EECONFIG
#include <avr/eeprom.h>
#endif
/**
\var heaters_pid
\brief this struct holds the heater PID factors
PID is a fascinating way to control any closed loop control, combining the error (P), cumulative error (I) and rate at which we're approacing the setpoint (D) in such a way that when correctly tuned, the system will achieve target temperature quickly and with little to no overshoot
At every sample, we calculate \f$OUT = k_P (S - T) + k_I \int (S - T) + k_D \frac{dT}{dt}\f$ where S is setpoint and T is temperature.
The three factors kP, kI, kD are chosen to give the desired behaviour given the dynamics of the system.
See http://www.embedded.com/design/prototyping-and-development/4211211/PID-without-a-PhD for the full story
*/
struct {
int32_t p_factor; ///< scaled P factor: mibicounts/qc
int32_t i_factor; ///< scaled I factor: mibicounts/(qC*qs)
int32_t d_factor; ///< scaled D factor: mibicounts/(qc/(TH_COUNT*qs))
int16_t i_limit; ///< scaled I limit, such that \f$-i_{limit} < i_{factor} < i_{limit}\f$
} heaters_pid[NUM_HEATERS];
#ifdef EECONFIG
/// this lives in the eeprom so we can save our PID settings for each heater
typedef struct {
int32_t EE_p_factor;
int32_t EE_i_factor;
int32_t EE_d_factor;
int16_t EE_i_limit;
uint16_t crc; ///< crc so we can use defaults if eeprom data is invalid
} EE_factor;
EE_factor EEMEM EE_factors[NUM_HEATERS];
#endif /* EECONFIG */
heater_runtime_t heaters_runtime[NUM_HEATERS];
/** Inititalise PID data structures.
\param i Index of the heater to initialise by Teacup numbering.
*/
void pid_init() {
uint8_t i;
for (i = 0; i < NUM_HEATERS; i++) {
#ifdef HEATER_SANITY_CHECK
// 0 is a "sane" temperature when we're trying to cool down.
heaters_runtime[i].sane_temperature = 0;
#endif
#ifndef BANG_BANG
#ifdef EECONFIG
// Read factors from EEPROM.
heaters_pid[i].p_factor =
eeprom_read_dword((uint32_t *)&EE_factors[i].EE_p_factor);
heaters_pid[i].i_factor =
eeprom_read_dword((uint32_t *)&EE_factors[i].EE_i_factor);
heaters_pid[i].d_factor =
eeprom_read_dword((uint32_t *)&EE_factors[i].EE_d_factor);
heaters_pid[i].i_limit =
eeprom_read_word((uint16_t *)&EE_factors[i].EE_i_limit);
if (crc_block(&heaters_pid[i].p_factor, 14) !=
eeprom_read_word((uint16_t *)&EE_factors[i].crc))
#endif /* EECONFIG */
{
heaters_pid[i].p_factor = DEFAULT_P;
heaters_pid[i].i_factor = DEFAULT_I;
heaters_pid[i].d_factor = DEFAULT_D;
heaters_pid[i].i_limit = DEFAULT_I_LIMIT;
}
#endif /* BANG_BANG */
}
}
/** \brief run heater PID algorithm
\param h which heater we're running the loop for
\param type which temp sensor type this heater is attached to
\param current_temp the temperature that the associated temp sensor is reporting
\param target_temp the temperature we're trying to achieve
*/
void heater_tick(heater_t h, temp_type_t type, uint16_t current_temp, uint16_t target_temp) {
// Static, so it's not mandatory to calculate a new value, see BANG_BANG.
static uint8_t pid_output;
#ifndef BANG_BANG
int16_t heater_p;
int16_t heater_d;
int16_t t_error = target_temp - current_temp;
#endif /* BANG_BANG */
if (h >= NUM_HEATERS)
return;
if (target_temp == 0) {
heater_set(h, 0);
return;
}
#ifndef BANG_BANG
heaters_runtime[h].temp_history[heaters_runtime[h].temp_history_pointer++] = current_temp;
heaters_runtime[h].temp_history_pointer &= (TH_COUNT - 1);
// PID stuff
// proportional
heater_p = t_error; // Units: qC where 4qC=1C
// integral
heaters_runtime[h].heater_i += t_error; // Units: qC*qs where 16qC*qs=1C*s
// prevent integrator wind-up
if (heaters_runtime[h].heater_i > heaters_pid[h].i_limit)
heaters_runtime[h].heater_i = heaters_pid[h].i_limit;
else if (heaters_runtime[h].heater_i < -heaters_pid[h].i_limit)
heaters_runtime[h].heater_i = -heaters_pid[h].i_limit;
// derivative. Units: qC/(TH_COUNT*qs) where 1C/s=TH_COUNT*4qC/4qs=8qC/qs)
// note: D follows temp rather than error so there's no large derivative when the target changes
heater_d = heaters_runtime[h].temp_history[heaters_runtime[h].temp_history_pointer] - current_temp;
// combine factors
int32_t pid_output_intermed = ( // Units: counts
(
(((int32_t) heater_p) * heaters_pid[h].p_factor) +
(((int32_t) heaters_runtime[h].heater_i) * heaters_pid[h].i_factor) +
(((int32_t) heater_d) * heaters_pid[h].d_factor)
) / PID_SCALE
);
// rebase and limit factors
if (pid_output_intermed > 255) {
if (t_error > 0)
heaters_runtime[h].heater_i -= t_error; // un-integrate
pid_output = 255;
}
else if (pid_output_intermed < 0) {
if (t_error < 0)
heaters_runtime[h].heater_i -= t_error; // un-integrate
pid_output = 0;
}
else
pid_output = pid_output_intermed & 0xFF;
if (DEBUG_PID && (debug_flags & DEBUG_PID))
sersendf_P(PSTR("T{E:%d, P:%d * %ld = %ld / I:%d * %ld = %ld / D:%d * %ld = %ld # O: %ld = %u}\n"), t_error, heater_p, heaters_pid[h].p_factor, (int32_t) heater_p * heaters_pid[h].p_factor / PID_SCALE, heaters_runtime[h].heater_i, heaters_pid[h].i_factor, (int32_t) heaters_runtime[h].heater_i * heaters_pid[h].i_factor / PID_SCALE, heater_d, heaters_pid[h].d_factor, (int32_t) heater_d * heaters_pid[h].d_factor / PID_SCALE, pid_output_intermed, pid_output);
#else
if (current_temp >= target_temp + (TEMP_HYSTERESIS))
pid_output = BANG_BANG_OFF;
else if (current_temp <= target_temp - (TEMP_HYSTERESIS))
pid_output = BANG_BANG_ON;
// else keep pid_output
#endif
#ifdef HEATER_SANITY_CHECK
// check heater sanity
// implementation is a moving window with some slow-down to compensate for thermal mass
if (target_temp > (current_temp + (TEMP_HYSTERESIS*4))) {
// heating
if (current_temp > heaters_runtime[h].sane_temperature)
// hotter than sane- good since we're heating unless too hot
heaters_runtime[h].sane_temperature = current_temp;
else {
if (heaters_runtime[h].sanity_counter < 40)
heaters_runtime[h].sanity_counter++;
else {
heaters_runtime[h].sanity_counter = 0;
// ratchet up expected temp
heaters_runtime[h].sane_temperature++;
}
}
// limit to target, so if we overshoot by too much for too long an error is flagged
if (heaters_runtime[h].sane_temperature > target_temp)
heaters_runtime[h].sane_temperature = target_temp;
}
else if (target_temp < (current_temp - (TEMP_HYSTERESIS*4))) {
// cooling
if (current_temp < heaters_runtime[h].sane_temperature)
// cooler than sane- good since we're cooling
heaters_runtime[h].sane_temperature = current_temp;
else {
if (heaters_runtime[h].sanity_counter < 125)
heaters_runtime[h].sanity_counter++;
else {
heaters_runtime[h].sanity_counter = 0;
// ratchet down expected temp
heaters_runtime[h].sane_temperature--;
}
}
// if we're at or below 60 celsius, don't freak out if we can't drop any more.
if (current_temp <= 240)
heaters_runtime[h].sane_temperature = current_temp;
// limit to target, so if we don't cool down for too long an error is flagged
else if (heaters_runtime[h].sane_temperature < target_temp)
heaters_runtime[h].sane_temperature = target_temp;
}
// we're within HYSTERESIS of our target
else {
heaters_runtime[h].sane_temperature = current_temp;
heaters_runtime[h].sanity_counter = 0;
}
// compare where we're at to where we should be
if (labs((int16_t)(current_temp - heaters_runtime[h].sane_temperature)) > (TEMP_HYSTERESIS*4)) {
// no change, or change in wrong direction for a long time- heater is broken!
pid_output = 0;
sersendf_P(PSTR("!! heater %d or its temp sensor broken - temp is %d.%dC, target is %d.%dC, didn't reach %d.%dC in %d0 milliseconds\n"), h, current_temp >> 2, (current_temp & 3) * 25, target_temp >> 2, (target_temp & 3) * 25, heaters_runtime[h].sane_temperature >> 2, (heaters_runtime[h].sane_temperature & 3) * 25, heaters_runtime[h].sanity_counter);
}
#endif /* HEATER_SANITY_CHECK */
heater_set(h, pid_output);
}
/** \brief check whether all heaters are off
*/
uint8_t heaters_all_zero() {
uint8_t i;
for (i = 0; i < NUM_HEATERS; i++) {
if (heaters_runtime[i].heater_output)
return 0;
}
return 255;
}
#ifdef EECONFIG
/** \brief set heater P factor
\param index heater to change factor for
\param p scaled P factor
*/
void pid_set_p(heater_t index, int32_t p) {
#ifndef BANG_BANG
if (index >= NUM_HEATERS)
return;
heaters_pid[index].p_factor = p;
#endif /* BANG_BANG */
}
/** \brief set heater I factor
\param index heater to change I factor for
\param i scaled I factor
*/
void pid_set_i(heater_t index, int32_t i) {
#ifndef BANG_BANG
if (index >= NUM_HEATERS)
return;
heaters_pid[index].i_factor = i;
#endif /* BANG_BANG */
}
/** \brief set heater D factor
\param index heater to change D factor for
\param d scaled D factor
*/
void pid_set_d(heater_t index, int32_t d) {
#ifndef BANG_BANG
if (index >= NUM_HEATERS)
return;
heaters_pid[index].d_factor = d;
#endif /* BANG_BANG */
}
/** \brief set heater I limit
\param index heater to set I limit for
\param i_limit scaled I limit
*/
void pid_set_i_limit(heater_t index, int32_t i_limit) {
#ifndef BANG_BANG
if (index >= NUM_HEATERS)
return;
heaters_pid[index].i_limit = i_limit;
#endif /* BANG_BANG */
}
/// \brief Write PID factors to eeprom
void heater_save_settings() {
#ifndef BANG_BANG
heater_t i;
for (i = 0; i < NUM_HEATERS; i++) {
eeprom_write_dword((uint32_t *) &EE_factors[i].EE_p_factor, heaters_pid[i].p_factor);
eeprom_write_dword((uint32_t *) &EE_factors[i].EE_i_factor, heaters_pid[i].i_factor);
eeprom_write_dword((uint32_t *) &EE_factors[i].EE_d_factor, heaters_pid[i].d_factor);
eeprom_write_word((uint16_t *) &EE_factors[i].EE_i_limit, heaters_pid[i].i_limit);
eeprom_write_word((uint16_t *) &EE_factors[i].crc, crc_block(&heaters_pid[i].p_factor, 14));
}
#endif /* BANG_BANG */
}
#endif /* EECONFIG */
#ifndef EXTRUDER
/** \brief send heater debug info to host
\param i index of heater to send info for
*/
void heater_print(uint16_t i) {
sersendf_P(PSTR("P:%ld I:%ld D:%ld Ilim:%u crc:%u\n"), heaters_pid[i].p_factor, heaters_pid[i].i_factor, heaters_pid[i].d_factor, heaters_pid[i].i_limit, crc_block(&heaters_pid[i].p_factor, 14));
}
#endif