read_p1_telegram.py

# DSMR P1 uitlezen
# (c) 10-2012 - GJ - gratis te kopieren en te plakken
# update Arne Kaas 10-08-2017

version = "2.0"
import sys
import serial
import signal, os

##############################################################################
#Main program
##############################################################################
print ("USB DSMR P1 telegram reader, version "+  version)
print ("Control-C to exit")

#Set COM port config
ser = serial.Serial()
ser.baudrate = 9600
ser.bytesize=serial.SEVENBITS
ser.parity=serial.PARITY_EVEN
ser.stopbits=serial.STOPBITS_ONE
ser.xonxoff=0
ser.rtscts=0
ser.timeout=20
ser.port="/dev/ttyUSB0" #use on raspberrypi ser.port="/dev/tty.usbserial-P11KXDOA"  # use for testing on macs


#Initialize empty telegram
telegram = ''

#set timeonut
def handler(signum, frame):
    ser.close()
    print("Error handler called with errornum: ", signum)
    raise OSError("No proper DSMR P1 telegram recieved.")

def read_DSMR_telegram():
    #Open COM port
    try:
        ser.open()
    except:
        sys.exit ("Coul not open serial '%s'. Aaaaarch."  % ser.name)
    
	# Set the signal handler and a 15-second alarm
    signal.signal(signal.SIGALRM, handler)
    signal.alarm(5)
    
    while True:
        #proces serial line to string
        p1_raw = ser.readline()
        p1_str=str(p1_raw)
        p1_line=p1_str.strip()
    
        #print for debugging purpose
        print (p1_line) 
    
        #add line to telegram
        telegram += str(p1_line) + '\n'
    
        # stop reading if '!' was found (DSMR telegram ends with it.)
        if p1_line == '!':
    	    #Close port and show status
    	    try:
    	        ser.close()
    	    except:	
    	        sys.exit ("Oops %s. Program aborted. Could not close serial port" % ser.name )
    	    break

    signal.alarm(0)          # Disable the alarm

try:
	read_DSMR_telegram()
except:
    print ("Increased baudrate to 19200, retrying serial")    
    try:
        ser.baudrate = 19200
        read_DSMR_telegram()
    except:
        print("19200 also failed")

text_file = open("logs/lastP1read.txt", "w")
text_file.write(telegram)
text_file.close()