Modbus TCP/IP Stream
This is a very simple module that uses NodeJS Streams2 to read Modbus TCP data and convert it to JSON and vice-versa.
If you're just starting or just trying to use this library, I advise you to try modbus-stream. It's more complete (it supports all standard function codes) and it was designed to work with TCP, RTU and ASCII modes.
npm install modbus-tcp
var modbus = ;var client = ;var server = ;// link client and server streams togetherclient;server;// if you have a socket (stream) you can just// call client.pipe(socket) or server.pipe(socket)server;// read coils from unit id = 0, from address 10 to 13client;
All of the following read methods have the form
method(unitId, from, to, next) and write methods have the form
method(unitId, addr, val, next), where
next is an optional function called if the server replies (with the same transactionId) to the sent message.
Addresses are exactly as is in protocol, so if you see a paper talking about address
40001 this usually means first record address of that function so it means address
This last event is triggered when an unknown function code is received.