Heater for threaded program
Dependents: LEX_Threaded_Programming_V3
Heater.cpp@48:cd2a9b799e89, 2019-12-17 (annotated)
- Committer:
- justinbuckland
- Date:
- Tue Dec 17 13:28:23 2019 +0000
- Revision:
- 48:cd2a9b799e89
- Parent:
- 47:06a9691d0a7b
- Child:
- 49:35fd40559960
Added R_SMOOTH = 0.9 (resistance value smoothed over 10 readings); enables proportional-only control, high gain, no oscillation
Who changed what in which revision?
User | Revision | Line number | New 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; |
justinbuckland | 46:47c394467c66 | 24 | R_smooth = 0; |
justinbuckland | 45:5f588512529b | 25 | R2_acc = 0; |
omatthews | 30:055d856f05b5 | 26 | } |
omatthews | 30:055d856f05b5 | 27 | |
omatthews | 2:7f15386fcc90 | 28 | void Heater::read() |
omatthews | 0:4e33cc8171f4 | 29 | { |
omatthews | 1:4435d407d827 | 30 | //Reads R and then resets the drive back to its previous value |
omatthews | 30:055d856f05b5 | 31 | int i = 0; |
omatthews | 17:0bfed0e96927 | 32 | double drive_prev = drive->read(); //Store previous value of drive |
justinbuckland | 35:5acf01897ed6 | 33 | |
justinbuckland | 44:e358867319f6 | 34 | *drive = 1.0f; //Turn the driver on for the measurement |
justinbuckland | 44:e358867319f6 | 35 | wait_us(thermal.settling_time_us); //Wait for ADC to settle |
justinbuckland | 34:294adcc3e4b2 | 36 | adc->start_conversion(ADC_CONV_ALL_CH); |
justinbuckland | 34:294adcc3e4b2 | 37 | |
omatthews | 18:f5d26d3d532f | 38 | //Incremental back off until ADC is free |
omatthews | 30:055d856f05b5 | 39 | while(adc_busy == 1) { |
omatthews | 30:055d856f05b5 | 40 | wait_us(1); |
omatthews | 30:055d856f05b5 | 41 | i++; |
omatthews | 30:055d856f05b5 | 42 | } |
omatthews | 25:09a315a59956 | 43 | |
justinbuckland | 44:e358867319f6 | 44 | drive->write(0); //Reset the duty cycle back to what it was |
omatthews | 18:f5d26d3d532f | 45 | |
omatthews | 18:f5d26d3d532f | 46 | //Get voltage, current and R values from the ADC conversion |
omatthews | 31:7c6f05326c4d | 47 | adc->read_channels(); |
omatthews | 31:7c6f05326c4d | 48 | curr = adc->read_channel_result(i_port); |
omatthews | 31:7c6f05326c4d | 49 | v = adc->read_channel_result(v_port); |
omatthews | 30:055d856f05b5 | 50 | |
justinbuckland | 35:5acf01897ed6 | 51 | if (curr > 0) { //Avoid dividing by 0 |
justinbuckland | 35:5acf01897ed6 | 52 | R = (float)v/curr; |
justinbuckland | 35:5acf01897ed6 | 53 | R = cal_a + cal_b*R; //Convert to Ohms |
omatthews | 30:055d856f05b5 | 54 | } |
justinbuckland | 42:166d9bc7675e | 55 | |
justinbuckland | 45:5f588512529b | 56 | // Calculate accumulated resistance values for R_avg and R_var output |
justinbuckland | 46:47c394467c66 | 57 | R_smooth = R_SMOOTH_FACTOR*R_smooth + (1-R_SMOOTH_FACTOR)*R; |
justinbuckland | 42:166d9bc7675e | 58 | R_acc = R_acc + R; |
justinbuckland | 46:47c394467c66 | 59 | R2_acc = R2_acc + R*R; |
justinbuckland | 42:166d9bc7675e | 60 | n_acc ++; |
justinbuckland | 35:5acf01897ed6 | 61 | |
omatthews | 0:4e33cc8171f4 | 62 | } |
omatthews | 0:4e33cc8171f4 | 63 | |
omatthews | 25:09a315a59956 | 64 | void Heater::update() |
omatthews | 7:59ece353eea2 | 65 | { |
justinbuckland | 44:e358867319f6 | 66 | |
justinbuckland | 41:b1602c68abcd | 67 | //Get error |
justinbuckland | 48:cd2a9b799e89 | 68 | //error = R_ref - R; // use single reading R values |
justinbuckland | 48:cd2a9b799e89 | 69 | error = R_ref - R_smooth; // use smoothed R values |
justinbuckland | 41:b1602c68abcd | 70 | |
omatthews | 25:09a315a59956 | 71 | //Update PWM from setpoint and resistance |
paullj | 39:5dffedda7a0d | 72 | double duty_cycle = thermal.pid_kp_mho * error; |
justinbuckland | 41:b1602c68abcd | 73 | |
justinbuckland | 48:cd2a9b799e89 | 74 | //Integral term (if used) |
justinbuckland | 48:cd2a9b799e89 | 75 | if (thermal.pid_integral_time_ms > 0) { // set integral time to zero to have no integral term |
justinbuckland | 41:b1602c68abcd | 76 | if (abs(error) > thermal.pid_wind_up_limit_ohm) error = error * thermal.pid_wind_up_limit_ohm / abs(error); |
justinbuckland | 41:b1602c68abcd | 77 | error_integrated += error * (float) thermal.thermal_control_loop_interval_ms; |
paullj | 39:5dffedda7a0d | 78 | duty_cycle += thermal.pid_kp_mho * error_integrated/thermal.pid_integral_time_ms; |
justinbuckland | 48:cd2a9b799e89 | 79 | } |
justinbuckland | 44:e358867319f6 | 80 | |
paullj | 39:5dffedda7a0d | 81 | if (duty_cycle > thermal.pid_pwm_limit) |
paullj | 39:5dffedda7a0d | 82 | duty_cycle = thermal.pid_pwm_limit; |
paullj | 39:5dffedda7a0d | 83 | else if (duty_cycle < 0) |
paullj | 39:5dffedda7a0d | 84 | duty_cycle = 0; |
justinbuckland | 36:a8130bd29349 | 85 | |
omatthews | 31:7c6f05326c4d | 86 | drive->write(duty_cycle); |
justinbuckland | 44:e358867319f6 | 87 | guard->write(duty_cycle * thermal.guard_drive_ratio); |
omatthews | 7:59ece353eea2 | 88 | } |
omatthews | 18:f5d26d3d532f | 89 | |
omatthews | 30:055d856f05b5 | 90 | void Heater::Set_ref(float R) |
omatthews | 19:fccdd7127f94 | 91 | { |
omatthews | 19:fccdd7127f94 | 92 | R_ref = R; |
omatthews | 19:fccdd7127f94 | 93 | } |
omatthews | 30:055d856f05b5 | 94 | void Heater::Set_D(float D) |
omatthews | 30:055d856f05b5 | 95 | { |
omatthews | 25:09a315a59956 | 96 | drive->write(D); |
omatthews | 26:f6c98b05ee85 | 97 | guard->write(D*thermal.guard_drive_ratio); |
omatthews | 30:055d856f05b5 | 98 | } |
omatthews | 0:4e33cc8171f4 | 99 | |
justinbuckland | 42:166d9bc7675e | 100 | float Heater::Get_D() const |
omatthews | 31:7c6f05326c4d | 101 | { |
omatthews | 31:7c6f05326c4d | 102 | return drive->read(); |
omatthews | 31:7c6f05326c4d | 103 | } |
omatthews | 31:7c6f05326c4d | 104 | |
omatthews | 30:055d856f05b5 | 105 | int Heater::Get_i() const |
omatthews | 30:055d856f05b5 | 106 | { |
omatthews | 30:055d856f05b5 | 107 | return curr; |
omatthews | 30:055d856f05b5 | 108 | } |
omatthews | 30:055d856f05b5 | 109 | int Heater::Get_v() const |
omatthews | 30:055d856f05b5 | 110 | { |
omatthews | 30:055d856f05b5 | 111 | return v; |
omatthews | 30:055d856f05b5 | 112 | } |
omatthews | 2:7f15386fcc90 | 113 | |
omatthews | 30:055d856f05b5 | 114 | float Heater::Get_R() const |
omatthews | 30:055d856f05b5 | 115 | { |
omatthews | 30:055d856f05b5 | 116 | return R; |
omatthews | 30:055d856f05b5 | 117 | } |
omatthews | 0:4e33cc8171f4 | 118 | |
justinbuckland | 42:166d9bc7675e | 119 | float Heater::Get_R_avg() |
justinbuckland | 42:166d9bc7675e | 120 | { |
justinbuckland | 42:166d9bc7675e | 121 | R_avg = R_acc / (float) n_acc; |
justinbuckland | 42:166d9bc7675e | 122 | return R_avg; |
justinbuckland | 42:166d9bc7675e | 123 | } |
justinbuckland | 42:166d9bc7675e | 124 | |
justinbuckland | 45:5f588512529b | 125 | float Heater::Get_R_var() // need to call Get_R_avg to calculate R_var before calling this function |
justinbuckland | 45:5f588512529b | 126 | { |
justinbuckland | 47:06a9691d0a7b | 127 | R_var = R2_acc / (float) n_acc - R_avg * R_avg; |
justinbuckland | 47:06a9691d0a7b | 128 | R_acc = 0; |
justinbuckland | 47:06a9691d0a7b | 129 | R2_acc = 0; |
justinbuckland | 47:06a9691d0a7b | 130 | n_acc = 0; |
justinbuckland | 45:5f588512529b | 131 | return R_var; |
justinbuckland | 45:5f588512529b | 132 | } |
justinbuckland | 45:5f588512529b | 133 | |
omatthews | 31:7c6f05326c4d | 134 | float Heater::Get_R_ref() const |
omatthews | 31:7c6f05326c4d | 135 | { |
omatthews | 31:7c6f05326c4d | 136 | return R_ref; |
omatthews | 31:7c6f05326c4d | 137 | } |
omatthews | 31:7c6f05326c4d | 138 | |
omatthews | 31:7c6f05326c4d | 139 | float Heater::Get_error() const |
omatthews | 31:7c6f05326c4d | 140 | { |
omatthews | 31:7c6f05326c4d | 141 | return error; |
omatthews | 31:7c6f05326c4d | 142 | } |
omatthews | 31:7c6f05326c4d | 143 | |
omatthews | 31:7c6f05326c4d | 144 | float Heater::Get_error_integrated() const |
omatthews | 31:7c6f05326c4d | 145 | { |
omatthews | 31:7c6f05326c4d | 146 | return error_integrated; |
omatthews | 31:7c6f05326c4d | 147 | } |
omatthews | 31:7c6f05326c4d | 148 | |
omatthews | 30:055d856f05b5 | 149 | void Heater::turn_on () |
omatthews | 19:fccdd7127f94 | 150 | { |
omatthews | 19:fccdd7127f94 | 151 | *drive = 1; |
omatthews | 26:f6c98b05ee85 | 152 | *guard = thermal.guard_drive_ratio; |
omatthews | 19:fccdd7127f94 | 153 | } |
omatthews | 1:4435d407d827 | 154 | |
omatthews | 30:055d856f05b5 | 155 | void Heater::turn_off () |
omatthews | 19:fccdd7127f94 | 156 | { |
omatthews | 19:fccdd7127f94 | 157 | *drive = 0; |
omatthews | 19:fccdd7127f94 | 158 | *guard = 0; |
omatthews | 19:fccdd7127f94 | 159 | } |