modbus-mqtt

Modbus-Mqtt

This module sends Modbus data to MQTT protocol

Supported Modbus Functions

Class	Function
FC1 "Read Coil Status"	readCoils(coil, len)
FC2 "Read Input Status"	readDiscreteInputs(addr, arg)
FC3 "Read Holding Registers"	readHoldingRegisters(addr, len)
FC4 "Read Input Registers"	readInputRegisters(addr, len)
FC43/14 "Read Device Identification" (supported ports: TCP, RTU)	readDeviceIdentification(id, obj)

MQTT Subscribe Topic Structure

modbus-iot/{modbusId}/{functionName}

Example; modbus-iot/12/readInputRegisters

Example

const ModbusMqtt = require('./index')

const options = {
  mqttOptions: {
    brokerUrl: 'mqtt://broker.mqttdashboard.com'
  },
  modbusOptions: {
    type: 'TCP',
    tcp: {
      ip: '127.0.0.1',
      port: 802
    },
    id: 1
  }
}

const modbusMqtt = new ModbusMqtt(options)

modbusMqtt.on('modbus-connect', () => {
  setInterval(() => {
    modbusMqtt.modbusClient.readInputRegisters(0, 10, (err, response) => {
      if (err) return console.log('Err ', err.message)
      console.log('READ INPUT REGISTERS ', response)
    })
  }, 1000)

  setInterval(() => {
    modbusMqtt.modbusClient.readInputRegisters(20, 10)
  }, 2000)
})