Print 'received from COM1: %s' % p1.stdout.readline() # print output from ReadCOM.py for COM1 print 'received from COM2: %s' % p2.stdout.readline() # print output from ReadCOM.The source code of all examples can be downloaded from here.Īlthough Bluetooth, Ethernet, or USB interfaces are commonly used for communication between a computer and peripherals (and I 2C, SPI and 1-Wire for microcontroller systems), the communication over the serial interface (RS-232C) is still widespread. Ser = serial.Serial(port=sys.argv,baudrate= int(sys.argv))Īnd after pass it in main.py: from subprocess import Popen, PIPE (output) # write output to stdoutįirst change ReadCOM.py to receive arguments import sys Ser.write( 'serial command here ') # send command to serial port Print 'received from COM1: %s' % p1.stdout.readline() # print output from ReadCOM.py for COM1 print 'received from COM2: %s' % p2.stdout.readline() # print output from ReadCOM.py for COM2 ReadCOM.py (taken from related post and edited) import sys P2 = Popen(, stdin=PIPE, stdout=PIPE, stderr=PIPE) # read COM2 permanently for i in range( 10): P1 = Popen(, stdin=PIPE, stdout=PIPE, stderr=PIPE) # read COM1 permanently # call subprocess # pass the serial object to subprocess # read out serial port # HOW TO PASS SERIAL OBJECT HERE to stdin main.py import serial # serial communication from subprocess import Popen, PIPE # now you have to wait at least 100ms for device 2 to respondĪnother approch is to parallelize the serial readings in subprocesses. Ser2.write( 'command for reading out device 2') Ser1.write( 'command for reading out device 1') Ser2 = serial.Serial(port= 'COM2',baudrate= 9600) The following approach ser1 = serial.Serial(port= 'COM1',baudrate= 9600) Because of timeout and readout times it isn't possible to read them out at the same time in one process. I want to read out 2 or more serial ports at the same time. I think I wasn't totally clear what i want to achieve. (Maybe this: How do I apply twisted serial ports to my problem?) EDIT The big problem is: how do I pass the serial port object to the subprocess?ĭoes another (and maybe better) solution exist to this? I want to read each serial port data in one subprocess for parallelization.in the main program I get all open serial ports, open them and append the serial object to serialobjects.I'm trying to read out multiple serial ports at the same time with Python 2.7 and PySerial.

Python serial port