53 lines
1.6 KiB
JavaScript
53 lines
1.6 KiB
JavaScript
'use strict';
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const Stampit = require('stampit');
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const Put = require('put');
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module.exports = Stampit()
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.init(function () {
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const FC = 1;
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let init = () => {
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this.log.debug('initiating read coils request handler.');
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this.responseDelay = this.responseDelay || 0;
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this.setRequestHandler(FC, onRequest);
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};
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let _onRequest = (pdu, cb) => {
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this.log.debug('handling read coils request.');
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if (pdu.length !== 5) {
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cb(Put().word8(0x81).word8(0x02).buffer());
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} else {
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const fc = pdu.readUInt8(0);
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const address = pdu.readUInt16BE(1);
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const byteAddress = address * 2;
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const value = pdu.readUInt16BE(3);
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this.emit('preWriteSingleRegisterRequest', byteAddress, value);
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let mem = this.getHolding();
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if (byteAddress + 2 > mem.length) {
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cb(Put().word8(0x86).word8(0x02).buffer());
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} else {
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let response = Put().word8(0x06).word16be(address).word16be(value).buffer();
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mem.writeUInt16BE(value, byteAddress);
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this.emit('postWriteSingleRegisterRequest', byteAddress, value);
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cb(response);
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}
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}
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};
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let onRequest = (pdu, cb) => {
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if (this.responseDelay) {
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setTimeout(_onRequest, this.responseDelay, pdu, cb);
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} else {
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setImmediate(_onRequest, pdu, cb);
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}
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};
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init();
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});
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