The Technology Partnership / Heater_V2

Heater for threaded program

Dependents:   LEX_Threaded_Programming_V3

Heater.cpp@44:e358867319f6, 2019-11-15 (annotated)

Committer:
justinbuckland
Date:
Fri Nov 15 15:59:32 2019 +0000
Revision:
44:e358867319f6
Parent:
43:d34ac9d8648c
Child:
45:5f588512529b
undo accidentally committed guard heater ratio variation with duty cycle

Who changed what in which revision?

UserRevisionLine numberNew contents of line
omatthews 0:4e33cc8171f4 1 /*------------------------------------------------------------------------------
omatthews 0:4e33cc8171f4 2 Library code file for interface to Heater
omatthews 0:4e33cc8171f4 3 Date: 16/07/2018
omatthews 0:4e33cc8171f4 4
omatthews 0:4e33cc8171f4 5
omatthews 0:4e33cc8171f4 6 ------------------------------------------------------------------------------*/
omatthews 1:4435d407d827 7 #include "mbed.h"
omatthews 1:4435d407d827 8 #include "MODSERIAL.h"
omatthews 0:4e33cc8171f4 9 #include "Heater.h"
omatthews 0:4e33cc8171f4 10 #include "ADS8568_ADC.h"
omatthews 0:4e33cc8171f4 11
justinbuckland 35:5acf01897ed6 12 Heater::Heater(const int i_port, const int v_port, const float cal_a, const float cal_b, FastPWM * drive, FastPWM * guard, ADS8568_ADC * adc, DigitalIn adc_busy, const memspcr_ThermalConfiguration & thermal)
justinbuckland 35:5acf01897ed6 13 :thermal(thermal), i_port(i_port), v_port(v_port), cal_a(cal_a), cal_b(cal_b), drive(drive), guard(guard), adc(adc), adc_busy(adc_busy)
omatthews 30:055d856f05b5 14 {
justinbuckland 42:166d9bc7675e 15 //Set up PWM
omatthews 30:055d856f05b5 16 drive->prescaler(1);
omatthews 30:055d856f05b5 17 guard->prescaler(1);
omatthews 30:055d856f05b5 18 drive->period_ticks(1000);
omatthews 30:055d856f05b5 19 guard->period_ticks(1000);
justinbuckland 42:166d9bc7675e 20
justinbuckland 42:166d9bc7675e 21 //Initialise values for averaging resistance
justinbuckland 42:166d9bc7675e 22 n_acc = 0;
justinbuckland 42:166d9bc7675e 23 R_acc = 0;
omatthews 30:055d856f05b5 24 }
omatthews 30:055d856f05b5 25
omatthews 2:7f15386fcc90 26 void Heater::read()
omatthews 0:4e33cc8171f4 27 {
omatthews 1:4435d407d827 28 //Reads R and then resets the drive back to its previous value
omatthews 30:055d856f05b5 29 int i = 0;
omatthews 17:0bfed0e96927 30 double drive_prev = drive->read(); //Store previous value of drive
justinbuckland 35:5acf01897ed6 31
justinbuckland 44:e358867319f6 32 *drive = 1.0f; //Turn the driver on for the measurement
justinbuckland 44:e358867319f6 33 wait_us(thermal.settling_time_us); //Wait for ADC to settle
justinbuckland 34:294adcc3e4b2 34 adc->start_conversion(ADC_CONV_ALL_CH);
justinbuckland 34:294adcc3e4b2 35
omatthews 18:f5d26d3d532f 36 //Incremental back off until ADC is free
omatthews 30:055d856f05b5 37 while(adc_busy == 1) {
omatthews 30:055d856f05b5 38 wait_us(1);
omatthews 30:055d856f05b5 39 i++;
omatthews 30:055d856f05b5 40 }
omatthews 25:09a315a59956 41
justinbuckland 44:e358867319f6 42 drive->write(0); //Reset the duty cycle back to what it was
omatthews 18:f5d26d3d532f 43
omatthews 18:f5d26d3d532f 44 //Get voltage, current and R values from the ADC conversion
omatthews 31:7c6f05326c4d 45 adc->read_channels();
omatthews 31:7c6f05326c4d 46 curr = adc->read_channel_result(i_port);
omatthews 31:7c6f05326c4d 47 v = adc->read_channel_result(v_port);
omatthews 30:055d856f05b5 48
justinbuckland 35:5acf01897ed6 49 if (curr > 0) { //Avoid dividing by 0
justinbuckland 35:5acf01897ed6 50 R = (float)v/curr;
justinbuckland 35:5acf01897ed6 51 R = cal_a + cal_b*R; //Convert to Ohms
omatthews 30:055d856f05b5 52 }
justinbuckland 42:166d9bc7675e 53
justinbuckland 42:166d9bc7675e 54 // Calcualate accumulated resistance values for R_avg output
justinbuckland 42:166d9bc7675e 55 R_acc = R_acc + R;
justinbuckland 42:166d9bc7675e 56 n_acc ++;
justinbuckland 35:5acf01897ed6 57
omatthews 0:4e33cc8171f4 58 }
omatthews 0:4e33cc8171f4 59
omatthews 25:09a315a59956 60 void Heater::update()
omatthews 7:59ece353eea2 61 {
justinbuckland 44:e358867319f6 62
justinbuckland 41:b1602c68abcd 63 //Get error
justinbuckland 41:b1602c68abcd 64 error = R_ref - R;
justinbuckland 41:b1602c68abcd 65
omatthews 25:09a315a59956 66 //Update PWM from setpoint and resistance
paullj 39:5dffedda7a0d 67 double duty_cycle = thermal.pid_kp_mho * error;
justinbuckland 41:b1602c68abcd 68
justinbuckland 41:b1602c68abcd 69 //Get integrated error
paullj 39:5dffedda7a0d 70 if (thermal.pid_integral_time_ms > 0) // set integral time to zero to have no integral term
justinbuckland 41:b1602c68abcd 71 if (abs(error) > thermal.pid_wind_up_limit_ohm) error = error * thermal.pid_wind_up_limit_ohm / abs(error);
justinbuckland 41:b1602c68abcd 72 error_integrated += error * (float) thermal.thermal_control_loop_interval_ms;
paullj 39:5dffedda7a0d 73 duty_cycle += thermal.pid_kp_mho * error_integrated/thermal.pid_integral_time_ms;
justinbuckland 44:e358867319f6 74
paullj 39:5dffedda7a0d 75 if (duty_cycle > thermal.pid_pwm_limit)
paullj 39:5dffedda7a0d 76 duty_cycle = thermal.pid_pwm_limit;
paullj 39:5dffedda7a0d 77 else if (duty_cycle < 0)
paullj 39:5dffedda7a0d 78 duty_cycle = 0;
justinbuckland 36:a8130bd29349 79
omatthews 31:7c6f05326c4d 80 drive->write(duty_cycle);
justinbuckland 44:e358867319f6 81 guard->write(duty_cycle * thermal.guard_drive_ratio);
omatthews 7:59ece353eea2 82 }
omatthews 18:f5d26d3d532f 83
omatthews 30:055d856f05b5 84 void Heater::Set_ref(float R)
omatthews 19:fccdd7127f94 85 {
omatthews 19:fccdd7127f94 86 R_ref = R;
omatthews 19:fccdd7127f94 87 }
omatthews 30:055d856f05b5 88 void Heater::Set_D(float D)
omatthews 30:055d856f05b5 89 {
omatthews 25:09a315a59956 90 drive->write(D);
omatthews 26:f6c98b05ee85 91 guard->write(D*thermal.guard_drive_ratio);
omatthews 30:055d856f05b5 92 }
omatthews 0:4e33cc8171f4 93
justinbuckland 42:166d9bc7675e 94 float Heater::Get_D() const
omatthews 31:7c6f05326c4d 95 {
omatthews 31:7c6f05326c4d 96 return drive->read();
omatthews 31:7c6f05326c4d 97 }
omatthews 31:7c6f05326c4d 98
omatthews 30:055d856f05b5 99 int Heater::Get_i() const
omatthews 30:055d856f05b5 100 {
omatthews 30:055d856f05b5 101 return curr;
omatthews 30:055d856f05b5 102 }
omatthews 30:055d856f05b5 103 int Heater::Get_v() const
omatthews 30:055d856f05b5 104 {
omatthews 30:055d856f05b5 105 return v;
omatthews 30:055d856f05b5 106 }
omatthews 2:7f15386fcc90 107
omatthews 30:055d856f05b5 108 float Heater::Get_R() const
omatthews 30:055d856f05b5 109 {
omatthews 30:055d856f05b5 110 return R;
omatthews 30:055d856f05b5 111 }
omatthews 0:4e33cc8171f4 112
justinbuckland 42:166d9bc7675e 113 float Heater::Get_R_avg()
justinbuckland 42:166d9bc7675e 114 {
justinbuckland 42:166d9bc7675e 115 R_avg = R_acc / (float) n_acc;
justinbuckland 42:166d9bc7675e 116 R_acc = 0;
justinbuckland 42:166d9bc7675e 117 n_acc = 0;
justinbuckland 42:166d9bc7675e 118 return R_avg;
justinbuckland 42:166d9bc7675e 119 }
justinbuckland 42:166d9bc7675e 120
omatthews 31:7c6f05326c4d 121 float Heater::Get_R_ref() const
omatthews 31:7c6f05326c4d 122 {
omatthews 31:7c6f05326c4d 123 return R_ref;
omatthews 31:7c6f05326c4d 124 }
omatthews 31:7c6f05326c4d 125
omatthews 31:7c6f05326c4d 126 float Heater::Get_error() const
omatthews 31:7c6f05326c4d 127 {
omatthews 31:7c6f05326c4d 128 return error;
omatthews 31:7c6f05326c4d 129 }
omatthews 31:7c6f05326c4d 130
omatthews 31:7c6f05326c4d 131 float Heater::Get_error_integrated() const
omatthews 31:7c6f05326c4d 132 {
omatthews 31:7c6f05326c4d 133 return error_integrated;
omatthews 31:7c6f05326c4d 134 }
omatthews 31:7c6f05326c4d 135
omatthews 30:055d856f05b5 136 void Heater::turn_on ()
omatthews 19:fccdd7127f94 137 {
omatthews 19:fccdd7127f94 138 *drive = 1;
omatthews 26:f6c98b05ee85 139 *guard = thermal.guard_drive_ratio;
omatthews 19:fccdd7127f94 140 }
omatthews 1:4435d407d827 141
omatthews 30:055d856f05b5 142 void Heater::turn_off ()
omatthews 19:fccdd7127f94 143 {
omatthews 19:fccdd7127f94 144 *drive = 0;
omatthews 19:fccdd7127f94 145 *guard = 0;
omatthews 19:fccdd7127f94 146 }