ModBus read and setup for Dio Smart MBSL32DI

configure.js

#!/usr/bin/env node

/*
 * ModBus configuration for Dio Smart MBSL32DI 32-channel digital input module
 * https://www.aliexpress.com/item/4001220947199.html
 */

////////////////
// CONFIGURATION
////////////////
const DEVICE = '/dev/ttyUSB0'

// possible values 1200, 2400, 4800, 9600, default 9600
const BAUD_RATE = 9600

// possible values 'even', 'odd', 'none', default 'none'
const PARITY = 'none'

// possible values 1-255, default 1
const ADDRESS = 1
////////////////////
// END CONFIGURATION
////////////////////

const ModbusRTU = require('modbus-serial')
// create an empty modbus client
const client = new ModbusRTU()
// open connection to a serial port
const promise = client
    .connectRTUBuffered(DEVICE, { baudRate: BAUD_RATE, parity: PARITY })
    // set timeout, if slave did not reply back
    .then(() => client.setTimeout(250))
    // run configure after connect
    .then(async () => {
        try {
            // set ID of slave
            await client.setID(ADDRESS);

            // write the new configuration
            await client.writeRegisters(0x0002, [
                // address between 1 and 255
                1,
                // baud rate:
                //   1 - 4800
                //   2 - 9600
                //   3 - 19200
                //   4 - 38400
                //   5 - 57600
                //   6 - 115200
                2,
                // parity check:
                //   1 - none
                //   2 - odd
                //   3 - even
                1
            ])
            console.log('Device configured')
        } catch (e) {
            // if error, handle them here (it should not)
            console.log(e)
        }
    })
    .then(async () => new Promise((resolve) => client.close(resolve)))

diosmart-mbsl32di.js

#!/usr/bin/env node

/*
 * ModBus read for Dio Smart MBSL32DI 32-channel digital input module
 * https://www.aliexpress.com/item/4001220947199.html
 */

////////////////
// CONFIGURATION
////////////////
const DEVICE = '/dev/ttyUSB0'

// possible values 1200, 2400, 4800, 9600, default 9600
const BAUD_RATE = 9600

// possible values 'even', 'odd', 'none', default 'none'
const PARITY = 'none'

// possible values 1-255, default 1
const ADDRESS = 1
////////////////////
// END CONFIGURATION
////////////////////

const ModbusRTU = require('modbus-serial')
// create an empty modbus client
const client = new ModbusRTU()
// open connection to a serial port
client.connectRTUBuffered(DEVICE, { baudRate: BAUD_RATE, parity: PARITY })
// set timeout, if slave did not reply back
client.setTimeout(250)

const getValue = async () => {
    try {
        // set ID of slave
        await client.setID(ADDRESS);

        // read the status of digital inputs
        let val = await client.readHoldingRegisters(0x0000, 7)
        // combine into single 32 bit integer
        const di = val.data[1] << 16 || val.data[0]

        const address = val.data[2]
        const baudRate = (v => {
            switch (v) {
                case 1: return 4800
                case 2: return 9600
                case 3: return 19200
                case 4: return 38400
                case 5: return 57600
                case 6: return 115200
                default: return `Unknown value for baud rate ${v}`
            }
        })(val.data[3])
        const parityCheck = (v => {
            switch (v) {
                case 1: return 'none'
                case 2: return 'odd'
                case 3: return 'even'
                default: return `Unknown value for parity check ${v}`
            }
        })(val.data[4])
        const productVersion = val.data[6]

        console.log({
            di,
            address,
            baudRate,
            parityCheck,
            productVersion
        })
    } catch(e){
        // if error, handle them here (it should not)
        console.log(e)
    } finally {
        // after get all data from salve repeate it again
        setImmediate(() => {
            getValue()
        })
    }
}

// start get value
getValue()

package.json

{
  "name": "test-modbus",
  "version": "1.0.0",
  "description": "",
  "author": "Geno Roupsky",
  "license": "ISC",
  "dependencies": {
    "modbus-serial": "^8.0.1"
  }
}