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https://github.com/yaacov/node-modbus-serial

A pure JavaScript implemetation of MODBUS-RTU (and TCP) for NodeJS
https://github.com/yaacov/node-modbus-serial

modbus-rtu modbus-serial modbus-tcp node-serialport

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A pure JavaScript implemetation of MODBUS-RTU (and TCP) for NodeJS

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# modbus-serial



A pure JavaScript implementation of MODBUS-RTU (Serial and TCP) for NodeJS.



[![NPM download](https://img.shields.io/npm/dm/modbus-serial.svg)](http://www.npm-stats.com/~packages/modbus-serial)

[![NPM version](https://badge.fury.io/js/modbus-serial.png)](http://badge.fury.io/js/modbus-serial)

![Build Status](https://github.com/yaacov/node-modbus-serial/workflows/ci/badge.svg)



Modbus is a serial communications protocol, first used in 1979.

Modbus is simple and robust, openly published, royalty-free and

easy to deploy and maintain.



**This package makes Modbus calls and serve fun and easy.**



----



- [What can I do with this module ?](#what-can-i-do-with-this-module-)

- [Compatibility](#compatibility)

- [Examples](#examples)

- [Methods](https://github.com/yaacov/node-modbus-serial/wiki/Methods)



----



#### Install



    npm install modbus-serial



try these options on npm install to build, if you have problems to install



    --unsafe-perm --build-from-source



#### What can I do with this module ?



This class makes it fun and easy to communicate with electronic

devices such as irrigation controllers, protocol droids and robots.

It talks with devices that use a serial line (e.g. RS485, RS232).

Many industrial electronic devices implement modbus.

Arduino can also talk modbus and you can control your projects and robots

using modbus.



Arduino libraries for modbus slave:

* https://github.com/yaacov/arduino-modbus-slave

* https://github.com/smarmengol/Modbus-Master-Slave-for-Arduino



Arduino sketch for irrigation timer with modbus support:

* https://github.com/yaacov/arduino-irrigation-timer



Node Modbus-WebSocket bridge:

* https://github.com/yaacov/node-modbus-ws



#### Compatibility



###### Version of NodeJS:

This module has not been tested on every single version of NodeJS. For best results you should stick to LTS versions, which are denoted by even major version numbers e.g. 4.x, 6.x, 8.x.



###### These classes are implemented:



| 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) ` |

| FC5 "Force Single Coil" | `writeCoil(coil, binary) //NOT setCoil` |

| FC6 "Preset Single Register" | `writeRegister(addr, value)` |

 | FC15 "Force Multiple Coil" | `writeCoils(addr, valueAry)` |

| FC16 "Preset Multiple Registers" | `writeRegisters(addr, valueAry)` |

| FC43/14 "Read Device Identification" (supported ports: TCP, RTU) | `readDeviceIdentification(id, obj)` |



###### Client Serial:



* modbus-RTU (SerialPort): Over serial line [require node serialport].

* modbus-RTU (RTUBufferedPort): Over buffered serial line [require node serialport].

* modbus-ASCII (AsciiPort): Over serial line [require node serialport].



###### Client TCP:



* modbus-TCP (TcpPort): Over TCP/IP line.

* modbus-RTU (UdpPort): Over C701 server, commercial UDP to serial bridge.

* modbus-RTU (TcpRTUBufferedPort): Over TCP/IP line, TCP/IP serial RTU buffered device.

* modbus-RTU (TelnetPort): Over Telnet server, TCP/IP serial bridge.



###### Server



* modbus-TCP (ServerTCP): Over TCP/IP line.



#### Examples



###### Read and Write

``` javascript

// create an empty modbus client

const ModbusRTU = require("modbus-serial");

const client = new ModbusRTU();



// open connection to a serial port

client.connectRTUBuffered("/dev/ttyUSB0", { baudRate: 9600 }, write);



function write() {

    client.setID(1);



    // write the values 0, 0xffff to registers starting at address 5

    // on device number 1.

    client.writeRegisters(5, [0 , 0xffff])

        .then(read);

}



function read() {

    // read the 2 registers starting at address 5

    // on device number 1.

    client.readHoldingRegisters(5, 2)

        .then(console.log);

}

```

----

###### Read on multiple slaves

``` javascript

const ModbusRTU = require("modbus-serial");

// create an empty modbus client

const client = new ModbusRTU();

// open connection to a serial port

client.connectRTUBuffered("/dev/ttyS0", { baudRate: 9600 });

// set timeout, if slave did not reply back

client.setTimeout(500);



// list of meter's id

const metersIdList = [10, 11, 12, 13, 14];



const getMetersValue = async (meters) => {

    try{

        // get value of all meters

        for(let meter of meters) {

            // output value to console

            console.log(await getMeterValue(meter));

            // wait 100ms before get another device

            await sleep(100);

	}

    } catch(e){

        // if error, handle them here (it should not)

        console.log(e)

    } finally {

        // after get all data from slave, repeat it again

        setImmediate(() => {

            getMetersValue(metersIdList);

        })

    }

}



const getMeterValue = async (id) => {

    try {

        // set ID of slave

        await client.setID(id);

        // read the 1 registers starting at address 0 (first register)

        let val =  await client.readInputRegisters(0, 1);

        // return the value

        return val.data[0];

    } catch(e){

        // if error return -1

        return -1

    }

}



const sleep = (ms) => new Promise(resolve => setTimeout(resolve, ms));



// start get value

getMetersValue(metersIdList);



```

----

###### Logger Serial

``` javascript

// create an empty modbus client

const ModbusRTU = require("modbus-serial");

const client = new ModbusRTU();



// open connection to a serial port

client.connectRTUBuffered("/dev/ttyUSB0", { baudRate: 9600 });

client.setID(1);



// read the values of 10 registers starting at address 0

// on device number 1. and log the values to the console.

setInterval(function() {

    client.readHoldingRegisters(0, 10, function(err, data) {

        console.log(data.data);

    });

}, 1000);

```

----

###### Logger TCP

``` javascript

// create an empty modbus client

const ModbusRTU = require("modbus-serial");

const client = new ModbusRTU();



// open connection to a tcp line

client.connectTCP("127.0.0.1", { port: 8502 });

client.setID(1);



// read the values of 10 registers starting at address 0

// on device number 1. and log the values to the console.

setInterval(function() {

    client.readHoldingRegisters(0, 10, function(err, data) {

        console.log(data.data);

    });

}, 1000);

```

----

###### Logger UDP

``` javascript

// create an empty modbus client

const ModbusRTU = require("modbus-serial");

const client = new ModbusRTU();



// open connection to a udp line

client.connectUDP("127.0.0.1", { port: 8502 });

client.setID(1);



// read the values of 10 registers starting at address 0

// on device number 1. and log the values to the console.

setInterval(function() {

    client.readHoldingRegisters(0, 10, function(err, data) {

        console.log(data.data);

    });

}, 1000);

```

----

###### ModbusTCP Server

``` javascript

// create an empty modbus client

const ModbusRTU = require("modbus-serial");

const vector = {

    getInputRegister: function(addr, unitID) {

        // Synchronous handling

        return addr;

    },

    getHoldingRegister: function(addr, unitID, callback) {

        // Asynchronous handling (with callback)

        setTimeout(function() {

            // callback = function(err, value)

            callback(null, addr + 8000);

        }, 10);

    },

    getCoil: function(addr, unitID) {

        // Asynchronous handling (with Promises, async/await supported)

        return new Promise(function(resolve) {

            setTimeout(function() {

                resolve((addr % 2) === 0);

            }, 10);

        });

    },

    setRegister: function(addr, value, unitID) {

        // Asynchronous handling supported also here

        console.log("set register", addr, value, unitID);

        return;

    },

    setCoil: function(addr, value, unitID) {

        // Asynchronous handling supported also here

        console.log("set coil", addr, value, unitID);

        return;

    },

    readDeviceIdentification: function(addr) {

        return {

            0x00: "MyVendorName",

            0x01: "MyProductCode",

            0x02: "MyMajorMinorRevision",

            0x05: "MyModelName",

            0x97: "MyExtendedObject1",

            0xAB: "MyExtendedObject2"

        };

    }

};



// set the server to answer for modbus requests

console.log("ModbusTCP listening on modbus://0.0.0.0:8502");

const serverTCP = new ModbusRTU.ServerTCP(vector, { host: "0.0.0.0", port: 8502, debug: true, unitID: 1 });



serverTCP.on("socketError", function(err){

    // Handle socket error if needed, can be ignored

    console.error(err);

});

```

----

###### Read and Write Modbus ASCII

``` javascript

// create an empty modbus client

const Modbus = require("modbus-serial");

const client = new Modbus();



// open connection to a serial port

client.connectAsciiSerial(

    "/dev/ttyUSB0", 

    {

        baudRate: 9600,

        startOfSlaveFrameChar: 0x3A  // optional: slave frame delimiter

    }, 

    write);



function write() {

    client.setID(1);



    // write the values 0, 0xffff to registers starting at address 5

    // on device number 1.

    client.writeRegisters(5, [0 , 0xffff])

        .then(read);

}



function read() {

    // read the 2 registers starting at address 5

    // on device number 1.

    client.readHoldingRegisters(5, 2)

        .then(console.log);

}

```

----

##### "modbusdb" is an elegant wrapper over the Modbus protocol



###### Check modbusdb github repo at https://github.com/yarosdev/modbusdb for more information, feedback is welcome!



Here is an example of using `modbusdb` wrapper over `modbus-serial`:



``` typescript

import Modbus from 'modbus-serial';

import { Modbusdb, ModbusSerialDriver, Datamap, createRegisterKey, TypeEnum, ScopeEnum } from "modbusdb";



// create an empty modbus client

const client = new Modbus();



client.connectTcpRTUBuffered("127.0.0.1", { port: 8502 }, app) // or use any other available connection methods



function app() {



  // First you need to define a schema for a database:

  // createRegisterKey(UNIT_ADDRESS, MODBUS_TABLE, REGISTER_ADDRESS, BIT_INDEX)

  const schema = [

    { key: createRegisterKey(1, ScopeEnum.InternalRegister, 10),    type: TypeEnum.Int16 },

    { key: createRegisterKey(1, ScopeEnum.InternalRegister, 11),    type: TypeEnum.Int32 },

    { key: createRegisterKey(1, ScopeEnum.PhysicalRegister, 99),    type: TypeEnum.UInt16 },

    { key: createRegisterKey(1, ScopeEnum.InternalRegister, 15, 2), type: TypeEnum.Bit },

  ];

  

  // Define unit-scoped config if needed:

  const units = [

    {

      address: 1, // This is unit address

      forceWriteMany: true, // Use 15(0x0f) and 16(0x10) functions for single register, default: false

      bigEndian: true, // You can use BigEndian for byte order, default: false

      swapWords: false, // This is applicable only for multi-registers types such as int32, float etc, default: false

      requestWithGaps: true, // If you are requesting addresses 10 and 13, allow to send one request to the device, default: true

      maxRequestSize: 32, // How many registers to be requested in one round-trip with device, default: 1

    }

  ];

  

  // Let`s create an instance of a database:

  const db = new Modbusdb({

    driver: new ModbusSerialDriver(client),

    datamap: new Datamap(schema, units)

  });



  // Now we can request three registers:

  // NOTICE: Modbusdb under the hood will make all needed requests for you in using an optimal plan

  //         If registers can be requested using a single request, be sure it will

  db.mget([

    createRegisterKey(1, ScopeEnum.InternalRegister, 10),

    createRegisterKey(1, ScopeEnum.InternalRegister, 11),

    createRegisterKey(1, ScopeEnum.PhysicalRegister, 99)

  ]).then(result => {

    console.log('mget', result)

  })



  // You can store register`s key to be used later:

  const speedSetPoint = createRegisterKey(1, ScopeEnum.InternalRegister, 10);

  const workingMode = createRegisterKey(1, ScopeEnum.InternalRegister, 11);

  

  // Write values directly into modbus device as easy as possible:

  // NOTICE: Modbusdb under the hood will make all needed requests for you

  //         Write operations have higher priority over the read operations

  db.mset([

    [speedSetPoint, 60],

    [workingMode, 10],

  ]).then(result => {

    console.log('mset', result)

  })

}

```

Enums:

```

ScopeEnum: (Modbus Table)

  1 = PhysicalState = Discrete Input

  2 = InternalState = Coil Status

  3 = PhysicalRegister = Input Register

  4 = InternalRegister = Holding Register

  

TypeEnum: (Available Data Types)

  1 = Bit,

  4 = Int16,

  5 = UInt16,

  6 = Int32,

  7 = UInt32,

  8 = Float

```



----



to get more see [Examples](https://github.com/yaacov/node-modbus-serial/wiki)



###### Serial connection



node-modbus-serial use node-serialport for serial communication, for serial port options settings

it passes to serial port the [openOptions](https://node-serialport.github.io/node-serialport/global.html#openOptions) object,

default serial port settings are 9600,8,n,1.



``` javascript

client.connectRTUBuffered("/dev/ttyUSB0", { baudRate: 9600, parity: 'even' });

```