The Technology Partnership / Heater_V2

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Dependents:   LEX_Threaded_Programming_V3

Heater.cpp@34:294adcc3e4b2, 2019-09-20 (annotated)

Committer:
justinbuckland
Date:
Fri Sep 20 14:53:54 2019 +0000
Revision:
34:294adcc3e4b2
Parent:
33:52ab0641f2e6
Child:
35:5acf01897ed6
Added board UID, ADC->Ohms resistance cal table; Added pressure control

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
omatthews 31:7c6f05326c4d 12 Heater::Heater(const int i_port, const int v_port, FastPWM * drive, FastPWM * guard, ADS8568_ADC * adc, DigitalIn adc_busy, const memspcr_ThermalConfiguration & thermal)
omatthews 31:7c6f05326c4d 13 :thermal(thermal), i_port(i_port), v_port(v_port), 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;
justinbuckland 34:294adcc3e4b2 25 float drive_cal[2] = {0.0, 10.0}; // replace with drive cal passed via Heater class
omatthews 17:0bfed0e96927 26 double drive_prev = drive->read(); //Store previous value of drive
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
omatthews 30:055d856f05b5 44 if (curr > 0) {
justinbuckland 34:294adcc3e4b2 45 R = (float)v/curr; //Avoid dividing by 0
justinbuckland 34:294adcc3e4b2 46 R = drive_cal[0] + drive_cal[1]*R; //Convert to Ohms
omatthews 30:055d856f05b5 47 }
omatthews 12:8a048f111140 48
omatthews 18:f5d26d3d532f 49 //Get error values
omatthews 17:0bfed0e96927 50 error = R_ref - R;
omatthews 30:055d856f05b5 51
omatthews 25:09a315a59956 52 //Only allow positive integrated errors and limit change in integrated error
omatthews 30:055d856f05b5 53 //to help avoid integral windup
omatthews 30:055d856f05b5 54
justinbuckland 34:294adcc3e4b2 55 if (abs(error) > thermal.pid_wind_up_limit_ohm) {error = error * thermal.pid_wind_up_limit_ohm / abs(error);}
omatthews 25:09a315a59956 56
omatthews 30:055d856f05b5 57 error_integrated += error;
omatthews 30:055d856f05b5 58
omatthews 30:055d856f05b5 59 if (error_integrated < 0.0) {
omatthews 30:055d856f05b5 60 error_integrated = 0.0;
omatthews 30:055d856f05b5 61 }
omatthews 0:4e33cc8171f4 62 }
omatthews 0:4e33cc8171f4 63
omatthews 25:09a315a59956 64 void Heater::update()
omatthews 7:59ece353eea2 65 {
omatthews 25:09a315a59956 66 //Update PWM from setpoint and resistance
paullj 33:52ab0641f2e6 67 double duty_cycle = (double) thermal.pid_kp_mho * (error + error_integrated/thermal.pid_integral_time_ms);
justinbuckland 34:294adcc3e4b2 68 if (duty_cycle > thermal.pid_pwm_limit) duty_cycle = thermal.pid_pwm_limit;
omatthews 31:7c6f05326c4d 69 drive->write(duty_cycle);
omatthews 31:7c6f05326c4d 70 guard->write(duty_cycle * thermal.guard_drive_ratio);
omatthews 7:59ece353eea2 71 }
omatthews 18:f5d26d3d532f 72
omatthews 30:055d856f05b5 73 void Heater::Set_ref(float R)
omatthews 19:fccdd7127f94 74 {
omatthews 19:fccdd7127f94 75 R_ref = R;
omatthews 19:fccdd7127f94 76 }
omatthews 30:055d856f05b5 77 void Heater::Set_D(float D)
omatthews 30:055d856f05b5 78 {
omatthews 25:09a315a59956 79 drive->write(D);
omatthews 26:f6c98b05ee85 80 guard->write(D*thermal.guard_drive_ratio);
omatthews 30:055d856f05b5 81 }
omatthews 0:4e33cc8171f4 82
omatthews 31:7c6f05326c4d 83 int Heater::Get_D() const
omatthews 31:7c6f05326c4d 84 {
omatthews 31:7c6f05326c4d 85 return drive->read();
omatthews 31:7c6f05326c4d 86 }
omatthews 31:7c6f05326c4d 87
omatthews 30:055d856f05b5 88 int Heater::Get_i() const
omatthews 30:055d856f05b5 89 {
omatthews 30:055d856f05b5 90 return curr;
omatthews 30:055d856f05b5 91 }
omatthews 30:055d856f05b5 92 int Heater::Get_v() const
omatthews 30:055d856f05b5 93 {
omatthews 30:055d856f05b5 94 return v;
omatthews 30:055d856f05b5 95 }
omatthews 2:7f15386fcc90 96
omatthews 30:055d856f05b5 97 float Heater::Get_R() const
omatthews 30:055d856f05b5 98 {
omatthews 30:055d856f05b5 99 return R;
omatthews 30:055d856f05b5 100 }
omatthews 0:4e33cc8171f4 101
omatthews 31:7c6f05326c4d 102 float Heater::Get_R_ref() const
omatthews 31:7c6f05326c4d 103 {
omatthews 31:7c6f05326c4d 104 return R_ref;
omatthews 31:7c6f05326c4d 105 }
omatthews 31:7c6f05326c4d 106
omatthews 31:7c6f05326c4d 107 float Heater::Get_error() const
omatthews 31:7c6f05326c4d 108 {
omatthews 31:7c6f05326c4d 109 return error;
omatthews 31:7c6f05326c4d 110 }
omatthews 31:7c6f05326c4d 111
omatthews 31:7c6f05326c4d 112 float Heater::Get_error_integrated() const
omatthews 31:7c6f05326c4d 113 {
omatthews 31:7c6f05326c4d 114 return error_integrated;
omatthews 31:7c6f05326c4d 115 }
omatthews 31:7c6f05326c4d 116
omatthews 30:055d856f05b5 117 void Heater::turn_on ()
omatthews 19:fccdd7127f94 118 {
omatthews 19:fccdd7127f94 119 *drive = 1;
omatthews 26:f6c98b05ee85 120 *guard = thermal.guard_drive_ratio;
omatthews 19:fccdd7127f94 121 }
omatthews 1:4435d407d827 122
omatthews 30:055d856f05b5 123 void Heater::turn_off ()
omatthews 19:fccdd7127f94 124 {
omatthews 19:fccdd7127f94 125 *drive = 0;
omatthews 19:fccdd7127f94 126 *guard = 0;
omatthews 19:fccdd7127f94 127 }