What can I do with this module ?

This class makes it easy to grab some data from device. Also, it handles typecast to int32, uint32, float etc. Type 'double' is not supported by nodejs...

Examples

Setup client and worker

const client = new ModbusRTU()

client.connect..........

client.setWorkerOptions({
    maxConcurrentRequests: 10, // it will send 10 requests or less at a time if any
    debug: true
})

Read some data

// Read 4 values starting from 10009 register. 
// Under the hood it will read 8 registers due to int32 type
const response = await client.send({
    unit: 1,
    fc: 3,
    address: 10009,
    quantity: 4,
    type: 'int32',
});

Write some data

// Write 2 values to address: 10009 and 10011
const response = await client.send({
    unit: 1,
    fc: 16,
    address: 10009,
    value: [10999, 10888],
    type: 'int32',
});

Poll some data

// It will build all READ requests for you in optimal way
const response = await client.poll({
    unit: 1,
    map: [
        { fc: 3, address: [10011, 10013, 10018], type: "int32" },
        { fc: 3, address: 10003, type: "int32" },
        { fc: 3, address: 10005, type: "int32" },
        { fc: 3, address: 10007, type: "int32" },
        { fc: 3, address: 10009, type: "int32" },
        { fc: 2, address: [1,2,3]},
        { fc: 1, address: [1,2,3]},
        { fc: 1, address: 4},
        { fc: 1, address: 5},
        { fc: 1, address: 6},
        { fc: 3, address: [10001]}, // default type is int16
        { fc: 3, address: [10020, 10023, 10026], type: "float"},
        { fc: 3, address: [10030, 10034], type: "double"}
    ],
    onProgress: (progress, data) => {
        console.log(
            progress, // Poll progress from 0...1 where 1 means 100%
            data,     // Data from the current request
        );
    },
    maxChunkSize: 32,  // max registers per request
    skipErrors: false, // if false it will stop poll and return PARTIAL result
})