RS232 Python Communication

[lemmi25]

Hi,

I am using the TinkerForge RS232 V2 Module and want to read sensor data.

This is my code

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# For this example connect the RX1 and TX pin to receive the send message

HOST = "localhost"
PORT = 4223
UID = "XXXX" # Change XYZ to the UID of your RS232 Bricklet 2.0

from tinkerforge.ip_connection import IPConnection
from tinkerforge.bricklet_rs232_v2 import BrickletRS232V2

import time

# Callback function for read callback
def rs232_data_received(data):

    test = ''.join(data)
    print(test)

if __name__ == "__main__":
    ipcon = IPConnection() # Create IP connection
    rs232 = BrickletRS232V2(UID, ipcon) # Create device object
    ipcon.connect(HOST, PORT) # Connect to brickd

    rs232.set_configuration(baudrate=9600,
                            parity=BrickletRS232V2.PARITY_NONE,
                            stopbits=BrickletRS232V2.STOPBITS_1,
                            wordlength=BrickletRS232V2.WORDLENGTH_8,
                            flowcontrol=BrickletRS232V2.FLOWCONTROL_OFF)

    # Don't use device before ipcon is connected

    print(rs232.get_chip_temperature())

    # Register read callback to function cb_read
    
    rs232.register_callback(rs232.CALLBACK_READ, rs232_data_received)

    # Enable read callback
    rs232.enable_read_callback()

    input("Press key to exit\n") # Use raw_input() in Python 2
    ipcon.disconnect()

 

The problem is, when I get the data output I only see unusual characters like this:

 

[
ý


¿

¿


å
ë
[
ý


å
ë

[
ý

 

When I use a FTDI Chip I can read the correct output (using pyserial). I also attached a LogicAnalyzer and the data shows fine. So I think it is a problem of converting the Data (Baudrate is correct).

Since I do not now what in the middle "layer" of TinkerForge is happening with the data, can someone please help me how to convert the data into correct ascii Numbers?

Many thanks

[photron]

Try replacing this

test = ''.join(data)

with this

test = [hex(ord(x)) for x in data]

This will give you a list of hex numbers.

[lemmi25]

Hey,

thanks for the fast reply. Getting the hex numbers is not my Problem. The character (when I convert the hex numbers) just make no sense. They should be numbers and or normal characters. Here is the datasheet from the sensor.

https://www.digikey.de/de/products/detail/gas-sensing-solutions-ltd/EXPLORIR-M-20/9952879

 

 

[photron]

How did you conect the sensor to the Bricklet? You have to connect it to the pin header which expects 3.3V TTL signals. You cannot connect it to the D-Sub 9 connector nor the terminal block, both expect RS232 voltage levels. I think you also need to power the sensor with 3.3V to make it output 3.3V TTL signals.

[lemmi25]

okay many thanks, that solved it ;)