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jsmodbus

Implementation for the Serial/TCP Modbus protocol.

A simple an easy to use Modbus TCP client/server implementation.

Modbus

Modbus is a simple Modbus TCP Client with a simple API.

Just type npm install jsmodbus and you are ready to go.

The test files are implemented using mocha and sinon.

Simply npm install -g mocha and npm install -g sinon. To run the tests type from the projects root folder mocha test/*.

Please feel free to fork and add your own tests.

var modbus = require('jsmodbus');
 
// create a modbus client 
var client = modbus.client.tcp.complete({ 
        'host'              : host, 
        'port'              : port,
        'autoReconnect'     : true,
        'reconnectTimeout'  : 1000,
        'timeout'           : 5000,
        'unitId'            : 0
    });
 
client.connect();
 
// reconnect with client.reconnect() 
 
client.on('connect', function () {
 
    // make some calls 
 
    client.readCoils(0, 13).then(function (resp) {
 
        // resp will look like { fc: 1, byteCount: 20, coils: [ values 0 - 13 ], payload: <Buffer> }  
        console.log(resp);
 
    }, console.error);
 
    client.readDiscreteInputs(0, 13).then(function (resp) {
 
        // resp will look like { fc: 2, byteCount: 20, coils: [ values 0 - 13 ], payload: <Buffer> }  
        console.log(resp);
 
    }, console.error);
 
    client.readHoldingRegisters(0, 10).then(function (resp) {
 
        // resp will look like { fc: 3, byteCount: 20, register: [ values 0 - 10 ], payload: <Buffer> } 
        console.log(resp); 
 
    }, console.error);
 
    client.readInputRegisters(0, 10).then(function (resp) {
 
        // resp will look like { fc: 4, byteCount: 20, register: [ values 0 - 10 ], payload: <Buffer> } 
        console.log(resp);
 
    }, console.error);
 
    client.writeSingleCoil(5, true).then(function (resp) {
 
        // resp will look like { fc: 5, byteCount: 4, outputAddress: 5, outputValue: true } 
        console.log(resp);
 
    }, console.error);
 
    client.writeSingleCoil(5, Buffer.from([0x01])).then(function (resp) {
 
        // resp will look like { fc: 5, byteCount: 4, outputAddress: 5, outputValue: true } 
        console.log(resp);
 
    }, console.error);
 
    client.writeSingleRegister(13, 42).then(function (resp) {
 
        // resp will look like { fc: 6, byteCount: 4, registerAddress: 13, registerValue: 42 } 
        console.log(resp);
 
    }, console.error);
 
    client.writeSingleRegister(13, Buffer.from([0x00 0x2A])).then(function (resp) {
 
        // resp will look like { fc: 6, byteCount: 4, registerAddress: 13, registerValue: 42 } 
        console.log(resp);
 
    }, console.error);
 
    client.writeMultipleCoils(3, [1, 0, 1, 0, 1, 1]).then(function (resp) {
 
        // resp will look like { fc: 15, startAddress: 3, quantity: 6 } 
        console.log(resp); 
 
    }, console.error);
 
    client.writeMultipleCoils(3, Buffer.from([0x2B]), 6).then(function (resp) {
 
        // resp will look like { fc: 15, startAddress: 3, quantity: 6 } 
        console.log(resp); 
 
    }, console.error);
 
    client.writeMultipleRegisters(4, [1, 2, 3, 4]).then(function (resp) {
        
        // resp will look like { fc : 16, startAddress: 4, quantity: 4 } 
        console.log(resp);
        
    }, console.error);
 
    client.writeMultipleRegisters(4, Buffer.from([0x00, 0x01, 0x00, 0x02, 0x00, 0x03, 0x00, 0x04]).then(function (resp) {
        
        // resp will look like { fc : 16, startAddress: 4, quantity: 4 } 
        console.log(resp);
        
    }, console.error);
 
});
 
client.on('error', function (err) {
 
    console.log(err);
    
})
    
    var stampit = require('stampit'),
        modbus = require('jsmodbus');
 
    var customServer = stampit()
        .refs({
            'logEnabled'        : true,
            'port'              : 8888,
            'responseDelay'     : 10, // so we do not fry anything when someone is polling this server 
 
            // specify coils, holding and input register here as buffer or leave it for them to be new Buffer(1024) 
            coils               : new Buffer(1024),
            holding             : new Buffer(1024),
            input               : new Buffer(1024)
        })
        .compose(modbus.server.tcp.complete)
        .init(function () {
        
            var init = function () {
 
                // get the coils with this.getCoils() [ Buffer(1024) ] 
                // get the holding register with this.getHolding() [ Buffer(1024) ] 
                // get the input register with this.getInput() [ Buffer(1024) ]                 
              
                // listen to requests  
 
                this.on('readCoilsRequest', function (start, quantity) {
                
                    // do something, this will be executed in sync before the  
                    // read coils request is executed  
                    
                });
 
                // the write request have pre and post listener 
                this.on('[pre][post]WriteSingleCoilRequest', function (address, value) {
                    
                    
                });
 
            }.bind(this);    
            
            
            init();
            
        });
 
    customServer();
 
    // you can of course always use a standard server like so 
 
    var server = modbus.server.tcp.complete({ port : 8888 });
 
    // and interact with the register via the getCoils(), getHolding() and getInput() calls 
 
    server.getHolding().writeUInt16BE(123, 1);

Copyright (C) 2016 Stefan Poeter (Stefan.Poeter[at]cloud-automation.de)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.