modbus

A simple interface for Modbus
* Read and write modbus registers
* One interface for both RTU and TCP
* Support for promises and callbacks

Quick Example

`` javascript
const modbus = require('modbus')

//Create a TCP Device
const device = modbus(ipAddress,port,unitId)

//Create an RTU Device
const device = modbus(commPort,baudRate)

//Read
let myCoil = await device.read('c0')
let myHoldingRegister = await device.read('hr0')
let myHoldingRegisters = await device.read('hr1-2')

//Write
await device.write('c0',true)
await device.write('hr0',15)

`

Device Object

Constructor

` javascript
const modbus = require('modbus')
const tcpDevice = modbus(ipAddress,port,unitId)
`

Properties

* ipAddress
* port
* unitId
* timeout
* online

Methods

$3

* address - Coil or register to read.
* callback(err,res) - Optional.

$3

* address - Coil or register to read.
* value - Data to write.
* callback(err,res) - Optional.

Address Syntax

[Short Hand + Register Number]

##### i.e.
* 'i8' - Descrite Input 8
* 'hr418' - Holding Register 418
* 'hr418-419' - Holding Registers 418 through 419

##### Applicable Datatypes
`
Data Type Short Hand Size Accessibility
Descrite Input i 1 Bit Read Only
Coil c 1 Bit Read / Write
Input Register ir 16 Bits Read Only
Holding Register hr 16 Bits Read / Write
`

Implemented Function Codes

* FC1 - Read Coil
* FC2 - Read Input
* FC3 - Read Holding Registers
* FC4 - Read Input Registers
* FC5 - Write Single Coil
* FC6 - Write Single Register
* FC15 - Write Multiple Coils
* FC16 - Write Multiple Registers

Recompile for Electron

If modbus is not compiled for the correct version of Node.js, you will not be able to communicate via Modbus RTU. (Modbus TCP is not affected)

When you install modbus it will compile against the version of Node.js on your machine, not against the Node.js runtime bundled with Electron.


To recompile modbus (or any native Node.js module) for Electron, you can use electron-rebuild

Install modbus:
`sh
npm i modbus
`

Install electron-rebuild with --save-dev:
`sh
npm install --save-dev electron-rebuild
`

Run electron-rebuild:
`sh
$(npm bin)/electron-rebuild
`

Or if you're on Windows:
`sh
.\node_modules\.bin\electron-rebuild.cmd
``