Temperature Measurement - owntech-foundation/Tutorials GitHub Wiki
The goal of this tutorial is to trigger temperature measurements with the TWIST board.
Required Hardware
- TWIST v_1_3 or later
- PC 64-bits (windows or linux)
- DC power supply (48 V, 2 A)
- Resistive load
- Oscilloscope or multimeter
Required Software
- Git
- Visual code studio
- Ownplot
Step-by-step implementation
0 - Owntech.ini
First, go to the platformio.ini file on the root, near the LICENSE file and uncomment line 45. As shown in the image below. It will automatically download the pid library that will be used in this tutorial.
lib_deps=
control_pid = https://gitlab.laas.fr/owntech/power-api/opalib-control-pid.git
control_library = https://github.com/owntech-foundation/control_library.git
owntech_examples = https://github.com/owntech-foundation/examples.git#0.0.8
- Use the following main.cpp code to deploy your closed loop voltage source.
/*
* Copyright (c) 2021-2024 LAAS-CNRS
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 2.1 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
* SPDX-License-Identifier: LGLPV2.1
*/
/**
* @brief This file it the main entry point of the
* OwnTech Power API. Please check the OwnTech
* documentation for detailed information on
* how to use Power API: https://docs.owntech.org/
*
* @author Clément Foucher <[email protected]>
* @author Luiz Villa <[email protected]>
* @author Ayoub Farah Hassan <[email protected]>
*/
//--------------OWNTECH APIs----------------------------------
#include "DataAPI.h"
#include "TaskAPI.h"
#include "TwistAPI.h"
#include "SpinAPI.h"
#include "opalib_control_pid.h"
#include "filters.h"
#include "zephyr/console/console.h"
#include "math.h"
/* ADC parameter */
#define TEMP_LEG1 EXTRA_MEAS
#define TEMP_LEG2 TEMP_SENSOR
/* Temperature computing parameter */
#define VREF 2.048f // voltage reference from ADC
#define QUANTUM_MAX 4096.0f // ADC resolution
#define R_DIVIDOR 20000.0f // Resistor in the voltage divider
#define Vin_dividor 3.3f // Input voltage in the voltage divider
#define R0_temp_sensor 10000.0f // R0 parameter of the termistor
#define T0_temp_sensor 298.15f // 25°C = 298.15K
#define B_temp_sensor 3450.0f // B parameter of the termistor
//--------------SETUP FUNCTIONS DECLARATION-------------------
void setup_routine(); // Setups the hardware and software of the system
//--------------LOOP FUNCTIONS DECLARATION--------------------
void loop_communication_task(); // code to be executed in the slow communication task
void loop_application_task(); // Code to be executed in the background task
void loop_critical_task(); // Code to be executed in real time in the critical task
//--------------USER VARIABLES DECLARATIONS-------------------
static uint32_t control_task_period = 100; //[us] period of the control task
static bool pwm_enable = false; //[bool] state of the PWM (ctrl task)
uint8_t received_serial_char;
/* Measure variables */
static float32_t V1_low_value;
static float32_t V2_low_value;
static float32_t I1_low_value;
static float32_t I2_low_value;
static float32_t I_high;
static float32_t V_high;
static float32_t temp_meas1;
static float32_t temp_meas2;
static float meas_data; // temp storage meas value (ctrl task)
float32_t duty_cycle = 0.3;
static float32_t voltage_reference = 25; //voltage reference
/* PID coefficient for a 8.6ms step response*/
static float32_t kp = 0.000215;
static float32_t ki = 2.86;
static float32_t kd = 0.0;
LowPassFirstOrderFilter filter_temp1(100e-3, 10); // filter for temp1 measure
LowPassFirstOrderFilter filter_temp2(100e-3, 10); // filter for temp2 measure
//---------------------------------------------------------------
enum serial_interface_menu_mode // LIST OF POSSIBLE MODES FOR THE OWNTECH CONVERTER
{
IDLEMODE = 0,
POWERMODE
};
uint8_t mode = IDLEMODE;
//--------------SETUP FUNCTIONS-------------------------------
float32_t temp_degree(float32_t voltage_quantum)
{
float32_t V_adc = (voltage_quantum/QUANTUM_MAX)*VREF;
float32_t R_t = ((V_adc/Vin_dividor)/(1 - V_adc/Vin_dividor))*R_DIVIDOR;
float32_t T = T0_temp_sensor/(1 + log(R_t/R0_temp_sensor)*(T0_temp_sensor/B_temp_sensor));
return T - 273.15f; // return value in degree
}
/**
* This is the setup routine.
* It is used to call functions that will initialize your spin, twist, data and/or tasks.
* In this example, we setup the version of the spin board and a background task.
* The critical task is defined but not started.
*/
void setup_routine()
{
// Setup the hardware first
spin.version.setBoardVersion(TWIST_v_1_1_2);
twist.setVersion(shield_TWIST_V1_3);
/* buck voltage mode */
twist.initAllBuck();
data.enableTwistDefaultChannels();
data.enableShieldChannel(4, TEMP_LEG1);
data.enableShieldChannel(3, TEMP_LEG2);
opalib_control_init_interleaved_pid(kp, ki, kd, control_task_period);
// Then declare tasks
uint32_t app_task_number = task.createBackground(loop_application_task);
uint32_t com_task_number = task.createBackground(loop_communication_task);
task.createCritical(loop_critical_task, 100); // Uncomment if you use the critical task
// Finally, start tasks
task.startBackground(app_task_number);
task.startBackground(com_task_number);
task.startCritical(); // Uncomment if you use the critical task
}
//--------------LOOP FUNCTIONS--------------------------------
void loop_communication_task()
{
while (1)
{
received_serial_char = console_getchar();
switch (received_serial_char)
{
case 'h':
//----------SERIAL INTERFACE MENU-----------------------
printk(" ________________________________________\n");
printk("| ------- MENU --------- |\n");
printk("| press i : idle mode |\n");
printk("| press s : serial mode |\n");
printk("| press p : power mode |\n");
printk("| press u : duty cycle UP |\n");
printk("| press d : duty cycle DOWN |\n");
printk("|________________________________________|\n\n");
//------------------------------------------------------
break;
case 'i':
printk("idle mode\n");
mode = IDLEMODE;
break;
case 'p':
printk("power mode\n");
mode = POWERMODE;
break;
case 'u':
voltage_reference += 0.5;
break;
case 'd':
voltage_reference -= 0.5;
break;
default:
break;
}
}
}
/**
* This is the code loop of the background task
* It is executed second as defined by it suspend task in its last line.
* You can use it to execute slow code such as state-machines.
*/
void loop_application_task()
{
data.triggerAcquisition(3);
meas_data = data.getLatest(TEMP_LEG2);
if (meas_data != NO_VALUE){
float32_t meas_filter = filter_temp1.calculateWithReturn(meas_data);
temp_meas2 = temp_degree(meas_filter);
}
data.triggerAcquisition(4);
meas_data = data.getLatest(TEMP_LEG1);
if (meas_data != NO_VALUE)
{
float32_t meas_filter = filter_temp2.calculateWithReturn(meas_data);
temp_meas1 = temp_degree(meas_filter);
}
if (mode == IDLEMODE)
{
spin.led.turnOff();
}
else if (mode == POWERMODE)
{
spin.led.turnOn();
printk("%f:", temp_meas1);
printk("%f:", temp_meas2);
printk("%f:", I1_low_value);
printk("%f:", V1_low_value);
printk("%f:", I2_low_value);
printk("%f:", V2_low_value);
printk("%f:", I_high);
printk("%f\n", V_high);
}
task.suspendBackgroundMs(100);
}
/**
* This is the code loop of the critical task
* It is executed every 500 micro-seconds defined in the setup_software function.
* You can use it to execute an ultra-fast code with the highest priority which cannot be interruped.
* It is from it that you will control your power flow.
*/
void loop_critical_task()
{
meas_data = data.getLatest(I1_LOW);
if (meas_data < 10000 && meas_data > -10000)
I1_low_value = meas_data;
meas_data = data.getLatest(V1_LOW);
if (meas_data != -10000)
V1_low_value = meas_data;
meas_data = data.getLatest(V2_LOW);
if (meas_data != -10000)
V2_low_value = meas_data;
meas_data = data.getLatest(I2_LOW);
if (meas_data < 10000 && meas_data > -10000)
I2_low_value = meas_data;
meas_data = data.getLatest(I_HIGH);
if (meas_data < 10000 && meas_data > -10000)
I_high = meas_data;
meas_data = data.getLatest(V_HIGH);
if (meas_data != -10000)
V_high = meas_data;
if (mode == IDLEMODE)
{
if (pwm_enable == true)
{
twist.stopAll();
}
pwm_enable = false;
}
else if (mode == POWERMODE)
{
duty_cycle = opalib_control_interleaved_pid_calculation(voltage_reference, V1_low_value); // to work with LEG1
// duty_cycle = opalib_control_interleaved_pid_calculation(voltage_reference, V2_low_value); // to work with LEG2
twist.setAllDutyCycle(duty_cycle);
/* Set POWER ON */
if (!pwm_enable)
{
pwm_enable = true;
twist.startLeg(LEG1); // to work with lEG1
// twist.startLeg(LEG2); // to work with LEG2
}
}
}
/**
* This is the main function of this example
* This function is generic and does not need editing.
*/
int main(void)
{
setup_routine();
return 0;
}
Convert your power
- Now we will connect your TWIST board to the power supply and to the PC via the USBC.
- Connect the pins Vhigh and GND of the TWIST to the DC power supply (set its current limitation at 1 A).
- Connect the pins VLow1, Vlow2 and GND of the TWIST to a resistive load.
- Connect the USB-C connector of the SPIN to the PC thanks via an USB cable.
- Switch ON the DC power supply. Choose a voltage between 0 and 48 V.
-
Build
and Upload 
-
Use OwnPlot or Serial Monitor to visualize the data and control your power.