The Technology Partnership / Heater_V2

Heater for threaded program

Dependents:   LEX_Threaded_Programming_V3

Heater.cpp@41:b1602c68abcd, 2019-10-14 (annotated)

Committer:
justinbuckland
Date:
Mon Oct 14 14:15:51 2019 +0000
Revision:
41:b1602c68abcd
Parent:
39:5dffedda7a0d
Child:
42:166d9bc7675e
Moved error calculation into Heater::update;

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 {
omatthews 30:055d856f05b5 15 drive->prescaler(1);
omatthews 30:055d856f05b5 16 guard->prescaler(1);
omatthews 30:055d856f05b5 17 drive->period_ticks(1000);
omatthews 30:055d856f05b5 18 guard->period_ticks(1000);
omatthews 30:055d856f05b5 19 }
omatthews 30:055d856f05b5 20
omatthews 2:7f15386fcc90 21 void Heater::read()
omatthews 0:4e33cc8171f4 22 {
omatthews 1:4435d407d827 23 //Reads R and then resets the drive back to its previous value
omatthews 30:055d856f05b5 24 int i = 0;
omatthews 17:0bfed0e96927 25 double drive_prev = drive->read(); //Store previous value of drive
justinbuckland 35:5acf01897ed6 26
justinbuckland 34:294adcc3e4b2 27 *drive = 1.0f; //Turn the driver on for the measurement
justinbuckland 34:294adcc3e4b2 28 wait_us(thermal.settling_time_us); //Wait for ADC to settle
justinbuckland 34:294adcc3e4b2 29 adc->start_conversion(ADC_CONV_ALL_CH);
justinbuckland 34:294adcc3e4b2 30
omatthews 18:f5d26d3d532f 31 //Incremental back off until ADC is free
omatthews 30:055d856f05b5 32 while(adc_busy == 1) {
omatthews 30:055d856f05b5 33 wait_us(1);
omatthews 30:055d856f05b5 34 i++;
omatthews 30:055d856f05b5 35 }
omatthews 25:09a315a59956 36
omatthews 20:2d34a03ae57e 37 drive->write(0); //Reset the duty cycle back to what it was
omatthews 18:f5d26d3d532f 38
omatthews 18:f5d26d3d532f 39 //Get voltage, current and R values from the ADC conversion
omatthews 31:7c6f05326c4d 40 adc->read_channels();
omatthews 31:7c6f05326c4d 41 curr = adc->read_channel_result(i_port);
omatthews 31:7c6f05326c4d 42 v = adc->read_channel_result(v_port);
omatthews 30:055d856f05b5 43
justinbuckland 35:5acf01897ed6 44 if (curr > 0) { //Avoid dividing by 0
justinbuckland 35:5acf01897ed6 45 R = (float)v/curr;
justinbuckland 35:5acf01897ed6 46 R = cal_a + cal_b*R; //Convert to Ohms
omatthews 30:055d856f05b5 47 }
justinbuckland 35:5acf01897ed6 48
omatthews 0:4e33cc8171f4 49 }
omatthews 0:4e33cc8171f4 50
omatthews 25:09a315a59956 51 void Heater::update()
omatthews 7:59ece353eea2 52 {
justinbuckland 41:b1602c68abcd 53
justinbuckland 41:b1602c68abcd 54 //Get error
justinbuckland 41:b1602c68abcd 55 error = R_ref - R;
justinbuckland 41:b1602c68abcd 56
omatthews 25:09a315a59956 57 //Update PWM from setpoint and resistance
paullj 39:5dffedda7a0d 58 double duty_cycle = thermal.pid_kp_mho * error;
justinbuckland 41:b1602c68abcd 59
justinbuckland 41:b1602c68abcd 60 //Get integrated error
paullj 39:5dffedda7a0d 61 if (thermal.pid_integral_time_ms > 0) // set integral time to zero to have no integral term
justinbuckland 41:b1602c68abcd 62 if (abs(error) > thermal.pid_wind_up_limit_ohm) error = error * thermal.pid_wind_up_limit_ohm / abs(error);
justinbuckland 41:b1602c68abcd 63 error_integrated += error * (float) thermal.thermal_control_loop_interval_ms;
paullj 39:5dffedda7a0d 64 duty_cycle += thermal.pid_kp_mho * error_integrated/thermal.pid_integral_time_ms;
justinbuckland 36:a8130bd29349 65
paullj 39:5dffedda7a0d 66 if (duty_cycle > thermal.pid_pwm_limit)
paullj 39:5dffedda7a0d 67 duty_cycle = thermal.pid_pwm_limit;
paullj 39:5dffedda7a0d 68 else if (duty_cycle < 0)
paullj 39:5dffedda7a0d 69 duty_cycle = 0;
justinbuckland 36:a8130bd29349 70
omatthews 31:7c6f05326c4d 71 drive->write(duty_cycle);
omatthews 31:7c6f05326c4d 72 guard->write(duty_cycle * thermal.guard_drive_ratio);
omatthews 7:59ece353eea2 73 }
omatthews 18:f5d26d3d532f 74
omatthews 30:055d856f05b5 75 void Heater::Set_ref(float R)
omatthews 19:fccdd7127f94 76 {
omatthews 19:fccdd7127f94 77 R_ref = R;
omatthews 19:fccdd7127f94 78 }
omatthews 30:055d856f05b5 79 void Heater::Set_D(float D)
omatthews 30:055d856f05b5 80 {
omatthews 25:09a315a59956 81 drive->write(D);
omatthews 26:f6c98b05ee85 82 guard->write(D*thermal.guard_drive_ratio);
omatthews 30:055d856f05b5 83 }
omatthews 0:4e33cc8171f4 84
omatthews 31:7c6f05326c4d 85 int Heater::Get_D() const
omatthews 31:7c6f05326c4d 86 {
omatthews 31:7c6f05326c4d 87 return drive->read();
omatthews 31:7c6f05326c4d 88 }
omatthews 31:7c6f05326c4d 89
omatthews 30:055d856f05b5 90 int Heater::Get_i() const
omatthews 30:055d856f05b5 91 {
omatthews 30:055d856f05b5 92 return curr;
omatthews 30:055d856f05b5 93 }
omatthews 30:055d856f05b5 94 int Heater::Get_v() const
omatthews 30:055d856f05b5 95 {
omatthews 30:055d856f05b5 96 return v;
omatthews 30:055d856f05b5 97 }
omatthews 2:7f15386fcc90 98
omatthews 30:055d856f05b5 99 float Heater::Get_R() const
omatthews 30:055d856f05b5 100 {
omatthews 30:055d856f05b5 101 return R;
omatthews 30:055d856f05b5 102 }
omatthews 0:4e33cc8171f4 103
omatthews 31:7c6f05326c4d 104 float Heater::Get_R_ref() const
omatthews 31:7c6f05326c4d 105 {
omatthews 31:7c6f05326c4d 106 return R_ref;
omatthews 31:7c6f05326c4d 107 }
omatthews 31:7c6f05326c4d 108
omatthews 31:7c6f05326c4d 109 float Heater::Get_error() const
omatthews 31:7c6f05326c4d 110 {
omatthews 31:7c6f05326c4d 111 return error;
omatthews 31:7c6f05326c4d 112 }
omatthews 31:7c6f05326c4d 113
omatthews 31:7c6f05326c4d 114 float Heater::Get_error_integrated() const
omatthews 31:7c6f05326c4d 115 {
omatthews 31:7c6f05326c4d 116 return error_integrated;
omatthews 31:7c6f05326c4d 117 }
omatthews 31:7c6f05326c4d 118
omatthews 30:055d856f05b5 119 void Heater::turn_on ()
omatthews 19:fccdd7127f94 120 {
omatthews 19:fccdd7127f94 121 *drive = 1;
omatthews 26:f6c98b05ee85 122 *guard = thermal.guard_drive_ratio;
omatthews 19:fccdd7127f94 123 }
omatthews 1:4435d407d827 124
omatthews 30:055d856f05b5 125 void Heater::turn_off ()
omatthews 19:fccdd7127f94 126 {
omatthews 19:fccdd7127f94 127 *drive = 0;
omatthews 19:fccdd7127f94 128 *guard = 0;
omatthews 19:fccdd7127f94 129 }