Correct Parameters to reply to writeMultipleRegisters

[EricPublic12]

I am trying to create a server and I need to send the reply after the client calls writeMultipleRegisters.
What are the correct parameters to send back and is there a helper function that will create the response?

[dresende]

You just need to reply the address of the first register and the number of registers written.

const modbus = require("modbus-stream");

modbus.tcp.server({ debug: null }, (connection) => {
	let one_hundred  = Buffer.alloc(2);
	let one_thousand = Buffer.alloc(2);
	let ten_thousand = Buffer.alloc(2);

	one_hundred.writeUInt16BE(100, 0);
	one_thousand.writeUInt16BE(1000, 0);
	ten_thousand.writeUInt16BE(10000, 0);

	connection.writeMultipleRegisters({ address: 123, values: [ one_hundred, one_thousand, ten_thousand ] }, (err, info) => {
		console.log("response", info.response);
	});
}).listen(12345, () => {
	modbus.tcp.connect(12345, { debug: null }, (err, connection) => {
		connection.on("write-multiple-registers", (info, reply) => {
			console.log("request", info.request);

			console.log("one hundred", info.request.values[0].readUInt16BE(0));
			console.log("one thousand", info.request.values[1].readUInt16BE(0));
			console.log("ten thousand", info.request.values[2].readUInt16BE(0));

			return reply(null, info.request.address, info.request.quantity);
		});
	});
});

[EricPublic12]

Are the same reply parameters used for writesingleRegister?

[dresende]

The responses are always based on standard. For writeSingleRegister you should return the address and the value written (instead of the quantity). Basically you just reply the same thing you receive.