# Monitoring of Electrical and Thermal Parameters in a Metal Part
# Introduction
This project aims to implement a data acquisition system for measuring temperature, voltage, and current in a metal part subjected to constant current, with the purpose of analyzing its electrical and thermal behavior in real time.
# Methodology
## Representative drawing
The image shows the parts that make up the experiment.
## Equipment
| Equipment | Model | Description | Pickture |
|---------|-------------|-------------|----------|
| Digit Multimeter PICOTEST | M3500A | Multimeter used to measure voltage | 
| Programmable DC Power Supply 0-30 V | PWS4305 | DC supply for powering the Pyrometer | 
| System DC Power Supply 150 V / 10 A | N5770A | DC source to heat the metal part | 
| Pyrometer CTLaser LT | OPTCTLLTSF | Pyrometer, temperature sensor | 
| Hot plate | IKA C-MAG HS7 | Heated bed with temperature control | 
| Digit Multimeter Tektronix | DMM4040 | Multimeter used to measure current | 
## Communication
### Communication with `Digit Multimeter M3500A` and `System DC Power Supply 150 V / 10 A`
To communicate the `Digit Multimeter M3500A` and the `System DC Power Supply 150 V / 10 A` a USB cable was used through the VISA protocol (Virtual Instrument Software Architecture) which is a standard for configuring, programming and debugging instrumentation systems that include GPIB interfaces. To do this, you first have to download the NI-VISA software on the computer you intend to use since Python is used to communicate through the Python wrapper `pyvisa` which requires the real VISA installation on the system. Otherwise an error will be thrown.
It is installed `pyvisa`:
```bash
pip install pyvisa
```
To find out if Pyvisa detects the instruments, run the following code in Python:
```python
import pyvisa
rm = pyvisa.ResourceManager()
print(rm.list_resources())
```
If a series of codes are displayed in the Terminal, it means the instruments have indeed been detected and are responding with their data. Something like this:
```Terminal
'USB0::0x164E::0x0DAD::TW00013644::INSTR'
```
### Communication with the Optris CTlaser pyrometer `OPTCTLLTSF`
Communication with the Optris CTlaser pyrometer was performed using the sensor's native binary protocol, using the Python programming language and the standard `pyserial` library for access to the COM port (virtual USB RS-232).
The sensor protocol consists of sending single-byte binary commands and receiving two-byte encoded responses, representing data such as temperature in `uint16` format.
Libraries used:
```python
import serial
import time
```
|communication parameters| |
---------------------------|----|
|Baudrate |115200 bps|
|Bits de datos |8|
|Paridad |Ninguna|
|Bits de parada |1|
|Timeout |1 segundo|
### Command to get temperature
```python
COMANDO_TEMPERATURA = bytes([0x01])
```
This command requests the process temperature (Tprocess). The sensor's response is 2 bytes, which must be interpreted using the following formula:
```python
temperatura = ((byte1 * 256 + byte2) - 1000) / 10
```
All this information was obtained from the manufacturer's manuals which are attached to this repository. [CTR-commands](https://gitea.itmorelia.com/delfin-25a/Experimento-de-Laboratorio-temperatura/src/branch/main/CTlaser-manual.pdf) and [CTlaser-manual](https://gitea.itmorelia.com/delfin-25a/Experimento-de-Laboratorio-temperatura/src/branch/main/CTlaser-manual.pdf)
#### Minimum code for pyrometer reading
```python
import serial
import time
sensor = serial.Serial('COM9', baudrate=9600, timeout=1)
time.sleep(2)
sensor.write(bytes([0x01])) #Comando para solicitar la temperatura
time.sleep(0.2)
respuesta = sensor.read(2)
if len(respuesta) == 2:
byte1, byte2 = respuesta[0], respuesta[1]
temperatura = ((byte1 * 256 + byte2) - 1000) / 10
print(f"Temperatura: {temperatura:.1f} °C")
else:
print("No se recibió respuesta válida.")
sensor.close()
```
### Communication with `Digit Multimeter Tektronix DMM4040`
Para poder establecer comunicación entre el multímetro digital **Tektronix DMM4040** y la computadora mediante una interfaz **RS-232**, utilizando Python y la librería **Pyvisa**. La comunicación se realiza por comandos **SCPI** (Standar Commands for Programmable Instruments), ampliamente utilizados en istrumentación electrónica.
Para poder comunicarnos con el multimetro es necesario tener un cable serial RS-232 a USB (adaptador compatible, ejemplo: PL2303, CH340, FTDI) y conectarlo tanto a la salida de datos serial del multimetro digital DMM4040 como a un puerto USB disponible en el computador, también, es necesario tener instalado el software de NI_VISA (Controlador requerido para comunicación serial por PyVISA), Python e instalar la librería `pyvisa`.
#### Código de ejemplo para conectar el multimetro DMM4040 con pyhton
```python
import pyvisa
import time
# Crear administrador VISA
rm = pyvisa.ResourceManager()
puerto = 'ASRL16::INSTR' # Asegurarse que este valor coincida con NI MAX
try:
multimetro = rm.open_resource(puerto)
# Configuración de la interfaz RS-232
multimetro.baud_rate = 9600
multimetro.data_bits = 8
multimetro.parity = pyvisa.constants.Parity.none
multimetro.stop_bits = pyvisa.constants.StopBits.one
multimetro.flow_control = pyvisa.constants.ControlFlow.none
multimetro.timeout = 5000
multimetro.write_termination = '\r\n'
multimetro.read_termination = '\r\n'
# Configurar medición de corriente DC (puedes usar VOLT:DC para voltaje)
multimetro.write("*CLS")
multimetro.write("CONF:CURR:DC")
multimetro.write("VOLT:DC:NPLC 1")
multimetro.write("TRIG:SOUR IMM")
multimetro.write("TRIG:DEL 0")
multimetro.write("SAMP:COUN 1")
# Iniciar y obtener la lectura
multimetro.write("INIT")
lectura = multimetro.query("FETCH?")
primera_lectura = lectura.strip().split(',')[0]
print("Corriente medida (DC):", primera_lectura, "A")
except Exception as e:
print("Error en la comunicación con el multímetro:", str(e))
```
## Code