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/*
* TipThermoModel.cpp
*
* Created on: 7 Oct 2019
* Author: ralim
*/
#include "TipThermoModel.h"
#include "BSP.h"
#include "Settings.h"
#include "configuration.h"
#include "main.hpp"
#include "power.hpp"
/*
* The hardware is laid out as a non-inverting op-amp
* There is a pullup of 39k(TS100) from the +ve input to 3.9V (1M pulup on TS100)
*
* The simplest case to model this, is to ignore the pullup resistors influence, and assume that its influence is mostly constant
* -> Tip resistance *does* change with temp, but this should be much less than the rest of the system.
*
* When a thermocouple is equal temperature at both sides (hot and cold junction), then the output should be 0uV
* Therefore, by measuring the uV when both are equal, the measured reading is the offset value.
* This is a mix of the pull-up resistor, combined with tip manufacturing differences.
*
* All of the thermocouple readings are based on this expired patent
* - > https://patents.google.com/patent/US6087631A/en
*
* This was bought to my attention by <Kuba Sztandera>
*/
uint32_t TipThermoModel::convertTipRawADCTouV(uint16_t rawADC, bool skipCalOffset) {
// This takes the raw ADC samples, converts these to uV
// Then divides this down by the gain to convert to the uV on the input to the op-amp (A+B terminals)
// Then remove the calibration value that is stored as a tip offset
uint32_t vddRailmVX10 = 33000; // The vreg is +-2%, but we have no higher accuracy available
// 4096 * 8 readings for full scale
// Convert the input ADC reading back into mV times 10 format.
uint32_t rawInputmVX10 = (rawADC * vddRailmVX10) / (4096 * 8);
uint32_t valueuV = rawInputmVX10 * 100; // shift into uV
// Now to divide this down by the gain
valueuV /= OP_AMP_GAIN_STAGE;
if (systemSettings.CalibrationOffset && skipCalOffset == false) {
// Remove uV tipOffset
if (valueuV > systemSettings.CalibrationOffset)
valueuV -= systemSettings.CalibrationOffset;
else
valueuV = 0;
}
return valueuV;
}
uint32_t TipThermoModel::convertTipRawADCToDegC(uint16_t rawADC) { return convertuVToDegC(convertTipRawADCTouV(rawADC)); }
uint32_t TipThermoModel::convertTipRawADCToDegF(uint16_t rawADC) { return convertuVToDegF(convertTipRawADCTouV(rawADC)); }
// Table that is designed to be walked to find the best sample for the lookup
// Extrapolate between two points
// [x1, y1] = point 1
// [x2, y2] = point 2
// x = input value
// output is x's interpolated y value
int32_t LinearInterpolate(int32_t x1, int32_t y1, int32_t x2, int32_t y2, int32_t x) { return y1 + (((((x - x1) * 1000) / (x2 - x1)) * (y2 - y1))) / 1000; }
#ifdef TEMP_uV_LOOKUP_HAKKO
const uint16_t uVtoDegC[] = {
//
//
0, 0, //
266, 10, //
522, 20, //
770, 30, //
1010, 40, //
1244, 50, //
1473, 60, //
1697, 70, //
1917, 80, //
2135, 90, //
2351, 100, //
2566, 110, //
2780, 120, //
2994, 130, //
3209, 140, //
3426, 150, //
3644, 160, //
3865, 170, //
4088, 180, //
4314, 190, //
4544, 200, //
4777, 210, //
5014, 220, //
5255, 230, //
5500, 240, //
5750, 250, //
6003, 260, //
6261, 270, //
6523, 280, //
6789, 290, //
7059, 300, //
7332, 310, //
7609, 320, //
7889, 330, //
8171, 340, //
8456, 350, //
8742, 360, //
9030, 370, //
9319, 380, //
9607, 390, //
9896, 400, //
10183, 410, //
10468, 420, //
10750, 430, //
11029, 440, //
11304, 450, //
11573, 460, //
11835, 470, //
12091, 480, //
12337, 490, //
12575, 500, //
};
#endif
#ifdef TEMP_uV_LOOKUP_TS80
const uint16_t uVtoDegC[] = {
//
//
530, 0, //
1282, 10, //
2034, 20, //
2786, 30, //
3538, 40, //
4290, 50, //
5043, 60, //
5795, 70, //
6547, 80, //
7299, 90, //
8051, 100, //
8803, 110, //
9555, 120, //
10308, 130, //
11060, 140, //
11812, 150, //
12564, 160, //
13316, 170, //
14068, 180, //
14820, 190, //
15573, 200, //
16325, 210, //
17077, 220, //
17829, 230, //
18581, 240, //
19333, 250, //
20085, 260, //
20838, 270, //
21590, 280, //
22342, 290, //
23094, 300, //
23846, 310, //
24598, 320, //
25350, 330, //
26103, 340, //
26855, 350, //
27607, 360, //
28359, 370, //
29111, 380, //
29863, 390, //
30615, 400, //
31368, 410, //
32120, 420, //
32872, 430, //
33624, 440, //
34376, 450, //
35128, 460, //
35880, 470, //
36632, 480, //
37385, 490, //
38137, 500, //
};
#endif
uint32_t TipThermoModel::convertuVToDegC(uint32_t tipuVDelta) {
if (tipuVDelta) {
int noItems = sizeof(uVtoDegC) / (2 * sizeof(uint16_t));
for (int i = 1; i < (noItems - 1); i++) {
// If current tip temp is less than current lookup, then this current lookup is the higher point to interpolate
if (tipuVDelta < uVtoDegC[i * 2]) {
return LinearInterpolate(uVtoDegC[(i - 1) * 2], uVtoDegC[((i - 1) * 2) + 1], uVtoDegC[i * 2], uVtoDegC[(i * 2) + 1], tipuVDelta);
}
}
return LinearInterpolate(uVtoDegC[(noItems - 2) * 2], uVtoDegC[((noItems - 2) * 2) + 1], uVtoDegC[(noItems - 1) * 2], uVtoDegC[((noItems - 1) * 2) + 1], tipuVDelta);
}
return 0;
}
uint32_t TipThermoModel::convertuVToDegF(uint32_t tipuVDelta) { return convertCtoF(convertuVToDegC(tipuVDelta)); }
uint32_t TipThermoModel::convertCtoF(uint32_t degC) {
//(Y °C × 9/5) + 32 =Y°F
return (32 + ((degC * 9) / 5));
}
uint32_t TipThermoModel::convertFtoC(uint32_t degF) {
//(Y°F − 32) × 5/9 = Y°C
if (degF < 32) {
return 0;
}
return ((degF - 32) * 5) / 9;
}
uint32_t TipThermoModel::getTipInC(bool sampleNow) {
int32_t currentTipTempInC = TipThermoModel::convertTipRawADCToDegC(getTipRawTemp(sampleNow));
currentTipTempInC += getHandleTemperature() / 10; // Add handle offset
// Power usage indicates that our tip temp is lower than our thermocouple temp.
// I found a number that doesn't unbalance the existing PID, causing overshoot.
// This could be tuned in concert with PID parameters...
currentTipTempInC -= x10WattHistory.average() / 25;
if (currentTipTempInC < 0)
return 0;
return currentTipTempInC;
}
uint32_t TipThermoModel::getTipInF(bool sampleNow) {
uint32_t currentTipTempInF = getTipInC(sampleNow);
currentTipTempInF = convertCtoF(currentTipTempInF);
return currentTipTempInF;
}
uint32_t TipThermoModel::getTipMaxInC() {
uint32_t maximumTipTemp = TipThermoModel::convertTipRawADCToDegC(0x7FFF - (21 * 5)); // back off approx 5 deg c from ADC max
maximumTipTemp += getHandleTemperature() / 10; // Add handle offset
return maximumTipTemp - 1;
}
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