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127 lines
6.4 KiB
Markdown
127 lines
6.4 KiB
Markdown
# Monitoring of Electrical and Thermal Parameters in a Metal Part
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# Introduction
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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.
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# Methodology
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## Representative drawing
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The image shows the parts that make up the experiment.
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## Equipment
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| Equipment | Model | Description | Pickture |
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|---------|-------------|-------------|----------|
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| Digit Multimeter PICOTEST | M3500A | Multimeter used to measure voltage | 
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| Programmable DC Power Supply 0-30 V | PWS4305 | DC supply for powering the Pyrometer | 
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| System DC Power Supply 150 V / 10 A | N5770A | DC source to heat the metal part | 
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| Pyrometer CTLaser LT | OPTCTLLTSF | Pyrometer, temperature sensor | 
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| Hot plate | IKA C-MAG HS7 | Heated bed with temperature control | 
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| Digit Multimeter Tektronix | DMM4040 | Multimeter used to measure current | 
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## Communication
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### Communication with `Digit Multimeter M3500A` and `System DC Power Supply 150 V / 10 A`
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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.
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<br>It is installed `pyvisa`:
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```bash
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pip install pyvisa
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```
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To find out if Pyvisa detects the instruments, run the following code in Python:
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```python
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import pyvisa
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rm = pyvisa.ResourceManager()
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print(rm.list_resources())
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```
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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:
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```Terminal
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'USB0::0x164E::0x0DAD::TW00013644::INSTR'
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```
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### Communication with the Optris CTlaser pyrometer `OPTCTLLTSF`
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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).
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<br>The sensor protocol consists of sending single-byte binary commands and receiving two-byte encoded responses, representing data such as temperature in `uint16` format.
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<br>Libraries used:
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```python
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import serial
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import time
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```
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|communication parameters| |
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---------------------------|----|
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|Baudrate |115200 bps|
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|Bits de datos |8|
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|Paridad |Ninguna|
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|Bits de parada |1|
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|Timeout |1 segundo|
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### Command to get temperature
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```python
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COMANDO_TEMPERATURA = bytes([0x01])
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```
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This command requests the process temperature (Tprocess). The sensor's response is 2 bytes, which must be interpreted using the following formula:
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```python
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temperatura = ((byte1 * 256 + byte2) - 1000) / 10
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```
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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)
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#### Minimum code for pyrometer reading
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```python
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import serial
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import time
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sensor = serial.Serial('COM9', baudrate=9600, timeout=1)
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time.sleep(2)
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sensor.write(bytes([0x01])) #Comando para solicitar la temperatura
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time.sleep(0.2)
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respuesta = sensor.read(2)
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if len(respuesta) == 2:
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byte1, byte2 = respuesta[0], respuesta[1]
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temperatura = ((byte1 * 256 + byte2) - 1000) / 10
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print(f"Temperatura: {temperatura:.1f} °C")
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else:
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print("No se recibió respuesta válida.")
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sensor.close()
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```
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### Communication with `Digit Multimeter Tektronix DMM4040`
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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.
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<br>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`.
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#### Código de ejemplo para conectar el multimetro DMM4040 con pyhton
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```python
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import pyvisa
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import time
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# Crear administrador VISA
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rm = pyvisa.ResourceManager()
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puerto = 'ASRL16::INSTR' # Asegurarse que este valor coincida con NI MAX
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try:
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multimetro = rm.open_resource(puerto)
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# Configuración de la interfaz RS-232
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multimetro.baud_rate = 9600
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multimetro.data_bits = 8
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multimetro.parity = pyvisa.constants.Parity.none
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multimetro.stop_bits = pyvisa.constants.StopBits.one
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multimetro.flow_control = pyvisa.constants.ControlFlow.none
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multimetro.timeout = 5000
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multimetro.write_termination = '\r\n'
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multimetro.read_termination = '\r\n'
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# Configurar medición de corriente DC (puedes usar VOLT:DC para voltaje)
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multimetro.write("*CLS")
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multimetro.write("CONF:CURR:DC")
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multimetro.write("VOLT:DC:NPLC 1")
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multimetro.write("TRIG:SOUR IMM")
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multimetro.write("TRIG:DEL 0")
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multimetro.write("SAMP:COUN 1")
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# Iniciar y obtener la lectura
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multimetro.write("INIT")
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lectura = multimetro.query("FETCH?")
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primera_lectura = lectura.strip().split(',')[0]
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print("Corriente medida (DC):", primera_lectura, "A")
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except Exception as e:
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print("Error en la comunicación con el multímetro:", str(e))
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```
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## Code |