first succesfull sdm120 module communication

pull.py

#!/usr/bin/env python3

# http://www.eastrongroup.com/data/uploads/Eastron_SDM120-Modbus_user_manual_2016_V2_6.pdf
# http://www.eastroneurope.com/media/_system/tech_specs/3914/SDM120%20PROTOCOL.pdf

from serial import *
from time import sleep


PORT_NAME = "/dev/ttyUSB0"
BAUD_RATE = 2400
PARITY = PARITY_NONE
PERIOD = 5


if __name__ == "__main__":

    while True:

        with Serial(PORT_NAME, BAUD_RATE, parity=PARITY, timeout=0.5) as port:
            #msg = b'\x01\x08\x00\x00\xAA\x55\x5E\x94'  # diagnostics (doesn't work - not implemented probably)
            msg = b'\x01\x03\x00\x00\x00\x02\xC4\x0B'  # read holding registers (answers)
            port.write(msg)
            answ = port.readlines()
            print(msg, answ)

        sleep(PERIOD)