Modbus_server.py

#! /usr/bin/env python3

"""Asynchronous Modbus Server Build in Python3 using the pyModbus module."""

from pymodbus.server.asynchronous import StartTcpServer
from pymodbus.device import ModbusDeviceIdentification
from pymodbus.datastore import ModbusSequentialDataBlock
from pymodbus.datastore import ModbusSlaveContext, ModbusServerContext

# create a datastore and populate it with test data
store = ModbusSlaveContext(
    di=ModbusSequentialDataBlock(0, [17]*100),        # Discrete inputs initializer
    co=ModbusSequentialDataBlock(0, [17]*100),        # Coils initializer
    hr=ModbusSequentialDataBlock(0, [17]*100),        # Holding register initializer
    ir=ModbusSequentialDataBlock(0, [17]*100))        # Input register initializer

context = ModbusServerContext(slaves=store, single=True)

# Populate the Modbus server information fields, these gert returned as responses to identity queries
identity = ModbusDeviceIdentification()
identity.VendorName = 'Pymodbus'
identity.ProductCode = 'PM'
identity.VendorUrl = 'https://github.com/riptideio/pyModbus'
identity.ProductName = 'Modbus Server'
identity.MajorMinorRevision = '1.0'

# Start the listening server
print('Starting Modbus server...')
StartTcpServer(context, identity=identity, address=('0.0.0.0', 502))