1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
|
/*
* PIDThread.cpp
*
* Created on: 29 May 2020
* Author: Ralim
*/
#include "BSP.h"
#include "FreeRTOS.h"
#include "Settings.h"
#include "TipThermoModel.h"
#include "cmsis_os.h"
#include "history.hpp"
#include "main.hpp"
#include "power.hpp"
#include "task.h"
static TickType_t powerPulseRate = 10000;
static TickType_t powerPulseDuration = 250;
TaskHandle_t pidTaskNotification = NULL;
uint32_t currentTempTargetDegC = 0; // Current temperature target in C
/* StartPIDTask function */
void startPIDTask(void const *argument __unused) {
/*
* We take the current tip temperature & evaluate the next step for the tip
* control PWM.
*/
setTipX10Watts(0); // disable the output driver if the output is set to be off
TickType_t lastPowerPulseStart = 0;
TickType_t lastPowerPulseEnd = 0;
history<int32_t, PID_TIM_HZ> tempError = {{0}, 0, 0};
currentTempTargetDegC = 0; // Force start with no output (off). If in sleep / soldering this will
// be over-ridden rapidly
pidTaskNotification = xTaskGetCurrentTaskHandle();
uint32_t PIDTempTarget = 0;
for (;;) {
if (ulTaskNotifyTake(pdTRUE, 2000)) {
// This is a call to block this thread until the ADC does its samples
int32_t x10WattsOut = 0;
// Do the reading here to keep the temp calculations churning along
uint32_t currentTipTempInC = TipThermoModel::getTipInC(true);
PIDTempTarget = currentTempTargetDegC;
if (PIDTempTarget) {
// Cap the max set point to 450C
if (PIDTempTarget > (450)) {
// Maximum allowed output
PIDTempTarget = (450);
}
// Safety check that not aiming higher than current tip can measure
if (PIDTempTarget > TipThermoModel::getTipMaxInC()) {
PIDTempTarget = TipThermoModel::getTipMaxInC();
}
// Convert the current tip to degree's C
// As we get close to our target, temp noise causes the system
// to be unstable. Use a rolling average to dampen it.
// We overshoot by roughly 1 degree C.
// This helps stabilize the display.
int32_t tError = PIDTempTarget - currentTipTempInC + 1;
tError = tError > INT16_MAX ? INT16_MAX : tError;
tError = tError < INT16_MIN ? INT16_MIN : tError;
tempError.update(tError);
// Now for the PID!
// P term - total power needed to hit target temp next cycle.
// thermal mass = 1690 milliJ/*C for my tip.
// = Watts*Seconds to raise Temp from room temp to +100*C, divided by 100*C.
// we divide milliWattsNeeded by 20 to let the I term dominate near the set point.
// This is necessary because of the temp noise and thermal lag in the system.
// Once we have feed-forward temp estimation we should be able to better tune this.
int32_t x10WattsNeeded = tempToX10Watts(tError);
// tempError.average());
// note that milliWattsNeeded is sometimes negative, this counters overshoot
// from I term's inertia.
x10WattsOut += x10WattsNeeded;
// I term - energy needed to compensate for heat loss.
// We track energy put into the system over some window.
// Assuming the temp is stable, energy in = energy transfered.
// (If it isn't, P will dominate).
x10WattsOut += x10WattHistory.average();
// D term - use sudden temp change to counter fast cooling/heating.
// In practice, this provides an early boost if temp is dropping
// and counters extra power if the iron is no longer losing temp.
// basically: temp - lastTemp
// Unfortunately, our temp signal is too noisy to really help.
}
// If the user turns on the option of using an occasional pulse to keep the power bank on
if (systemSettings.KeepAwakePulse) {
if (xTaskGetTickCount() - lastPowerPulseStart > powerPulseRate) {
lastPowerPulseStart = xTaskGetTickCount();
lastPowerPulseEnd = lastPowerPulseStart + powerPulseDuration;
}
// If current PID is less than the pulse level, check if we want to constrain to the pulse as the floor
if (x10WattsOut < systemSettings.KeepAwakePulse && xTaskGetTickCount() < lastPowerPulseEnd) {
x10WattsOut = systemSettings.KeepAwakePulse;
}
}
// Secondary safety check to forcefully disable header when within ADC noise of top of ADC
if (getTipRawTemp(0) > (0x7FFF - 150)) {
x10WattsOut = 0;
}
if (systemSettings.powerLimit && x10WattsOut > (systemSettings.powerLimit * 10)) {
setTipX10Watts(systemSettings.powerLimit * 10);
} else {
setTipX10Watts(x10WattsOut);
}
resetWatchdog();
} else {
// ADC interrupt timeout
setTipPWM(0);
}
}
}
|
