Run Modbus Tests with Server using pymodbus

description.md

Install requirements

sudo apt-get install python3-pymodbus (maybe python2 also works, but I didn't check)

Run

Server Code

(see modbus_server.py)

Client code

(see modbus_client.py)

modbus_client.py

#!/usr/bin/env python

from pymodbus.client.sync import ModbusTcpClient as ModbusClient

client = ModbusClient('localhost', port=5020)
client.connect()

res = client.read_holding_registers(1, 10, unit=1)
print(res.registers)

modbus_server.py

#!/usr/bin/env python
from pymodbus.server.sync import StartTcpServer

from pymodbus.datastore import ModbusSequentialDataBlock
from pymodbus.datastore import ModbusSlaveContext, ModbusServerContext


store = ModbusSlaveContext(
    di = ModbusSequentialDataBlock(0, [15]*100),
    co = ModbusSequentialDataBlock(0, [17]*100),
    hr = ModbusSequentialDataBlock(0, [18]*100),
    ir = ModbusSequentialDataBlock(0, [19]*100))
context = ModbusServerContext(slaves=store, single=True)

#‘di’ - Discrete Inputs initializer
#‘co’ - Coils initializer
#‘hr’ - Holding Register initializer
#‘ir’ - Input Registers iniatializer

StartTcpServer(context, identity=None, address=("localhost", 5020))