[How to use modbus_tk.py with unitronics]

some help from friends and this forum - here is the last version of the controller side

first added the close every 3 minutes - did not do the trick but helped a bit so i keep it there

init the card socket and port and set tcp keep, link lost and connection gave a stable read even when power or cable momentarily removed

 

[How to use modbus_tk.py with unitronics]

python on pc side

[How to use modbus_tk.py with unitronics]

Im just a nube so it took me a while to figure it out.

on the unitronix side assign a slave to one of the ports like this

on the python side read data with something like this

import modbus_tk
import modbus_tk.defines as cst
import modbus_tk.modbus as modbus
import modbus_tk.modbus_tcp as modbus_tcp
import logging

logger = modbus_tk.utils.create_logger("console", level=logging.DEBUG)

master = modbus_tcp.TcpMaster(host='172.21.2.183', port=20257, timeout_in_sec=5.0)
master.open
actual_bits = master.execute(slave=1, function_code=cst.READ_COILS, starting_address=1, quantity_of_x=2)
print("actual_bits =", actual_bits)

master.close

remember the slave number!

Hope this helps someone

 

[Modbus TCP or Modbus RTU over TCP?]

could anyone supply a full example of using modbus on the plc side AND on the pc side? 

I would prefer a python example but a .NET is good too.