micropython-modbus

Modbus Client and Server library for MicroPython STM32 devices. Based on pycom-modbus from pycom: https://github.com/pycom/pycom-modbus/

Usage

For client usage, simply put uModBusConst.py and uModBusFunctions.py, as well as one or both of uModBusSerial.py and uModBusTCP.py in the same directory as your main.py file.

For server usage, put uModBusConst.py and uModBusServer.py as well as one or both of uModBusSerialServer.py and uModBusSocketServer.py (once complete) in the same directory as the main.py file.

Examples

Serial Client

For this STM32 port, a UART (machine or pyb) object is passed in as the first argument. This helps facilitate the use of classes that build on the UART class, such as an RS485 class.

from uModBusSerial import uModBusSerial
from machine import UART

uart = UART(2, 9600)
modbus = uModbusSerial(uart, baudrate=9600)

regs = modbus.read_holding_registers(0, 0, 10)
print(regs)

(17, 17, 17, 17, 17, 17, 17, 17, 17, 17)

Serial Client with RS485 Class

from uModBusSerial import uModBusSerial
from rs485 import RS485

uart = RS485('E2', 'F11', 3, 9600)
modbus = uModbusSerial(uart, baudrate=9600)

regs = modbus.read_holding_registers(0, 0, 10)
print(regs)

(17, 17, 17, 17, 17, 17, 17, 17, 17, 17)

Serial Server

from uModBusSerialServer import uModBusSerialServer
from uModBusServer import uModBusSequentialDataBank
import pyb

uart = pyb.UART(2, 9600)
modbus = uModBusSerialServer(uart, 9600, 0,
                             di=uModBusSequentialDataBank(0, [0]*10),
                             co=uModBusSequentialDataBank(100, [1, 0, 1, 0, 1, 0, 1, 0, 1, 0]),
                             hr=uModBusSequentialDataBank(200, [42]*100),
                             ir=uModBusSequentialDataBank(1000, [1]*10))
while True:
    try:
        modbus.update()
        pyb.delay(250)
    except KeyboardInterrupt:
        break

Socket Server

import network
import pyb
from uModBusSocketServer import uModBusSocketServer
from uModBusServer import uModBusSequentialDataBank

### Initialize chosen nic.
### This example uses the EMAC, Inc. CutiPy with RS9116
### A network interface must be registerd for the socket module to work

nic = network.RS9116()
nic.init()
print("Connecting...")
nic.connect(ssid, psk)
print("Connected.")
host = nic.ifconfig()[0]
port = 502

###
###

modbus = uModBusSocketServer(host, port, 0,
                             di=uModBusSequentialDataBank(0, [0]*10),
                             co=uModBusSequentialDataBank(100, [1, 0, 1, 0, 1, 0, 1, 0, 1, 0]),
                             hr=uModBusSequentialDataBank(200, [42]*100),
                             ir=uModBusSequentialDataBank(1000, [1]*10))
while True:
    try:
        modbus.update()
        pyb.delay(250)
    except KeyboardInterrupt:
        break