modbus-connect/function-codes/report-slave-id.js

Modbus RTU over Web Serial and Node.js SerialPort

// function-codes/report-slave-id.js

const { FUNCTION_CODES } = require('../constants/constants.js');
const { allocUint8Array, isUint8Array } = require('../utils/utils.js');

/**
 * Строит PDU запроса Report Slave ID (0x11)
 * @returns {Uint8Array}
 */
function buildReportSlaveIdRequest() {
    const pdu = allocUint8Array(1);
    pdu[0] = FUNCTION_CODES.REPORT_SLAVE_ID;
    return pdu;
}

/**
 * Разбирает PDU ответа на Report Slave ID
 * @param {Uint8Array} pdu
 * @returns {{ slaveId: number, isRunning: boolean, data: Uint8Array }}
 */
function parseReportSlaveIdResponse(pdu) {
    if (!isUint8Array(pdu)) {
        throw new TypeError('PDU must be Uint8Array');
    }

    if (pdu[0] !== FUNCTION_CODES.REPORT_SLAVE_ID) {
        throw new Error(`Invalid function code: expected 0x11, got 0x${pdu[0].toString(16)}`);
    }

    const byteCount = pdu[1];

    if (pdu.length !== byteCount + 2) {
        throw new Error(`Invalid byte count: expected ${byteCount}, got ${pdu.length - 2}`);
    }

    const slaveId = pdu[2];
    const isRunning = pdu[3] === 0xFF;

    const data = pdu.slice(4); // Остальные байты — произвольные

    return { slaveId, isRunning, data };
}

module.exports = {
    buildReportSlaveIdRequest,
    parseReportSlaveIdResponse
}