node-opcua
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node-opcua
Publish on opcua server
Hello guys! I am using node opc ua, and I know how to do a subscription on opcua server, but I don't know how to do a publish on my opcua server. Anyone can help me please, or send me a example??
Thank You.
https://reference.opcfoundation.org/v104/Core/docs/Part4/5.13.1/
a datachange notification is triggered if the vlaue changes or the statuscode!
Thanks for your response. For example, imagine I want to send number of button clicks to opcua server, how I do that?
io.on('connection', function(client) {
//when the server receives clicked message, do this
client.on('clicked', function(data) {
clickCount++;
//send a message to ALL connected clients
io.emit('buttonUpdate', clickCount);
});
});
Websocketclient (sends msg) -> [ Websocketserver (onmessage updates Variable1) -> OPC UA Server (UAVariable: getter returns Variable1 value) ] -> OPC UA Client
I try, but dont do nothing.
My code in index.html:
My code in app.js:
And in inside on this function I want to update the state of variable on opcua server.
you could look into a example etienne made years ago https://github.com/node-opcua/node-opcua-htmlpanel but you need to swap the client with a server ^^
Its the link on example what I use as a base for my application. What do you say it was i need to create a server to send data to opc ua server ??
But I continue to don´t understand how is the process to send data to opcua server.
If you need my code to understand more what I am doing?? I send to your email, if you don´t mind.
Browser -> node.js application (websocketserver + opc ua server) Browser emits value -> websocketserver stores the value in a variable -> opc ua server's uavariable has a getter to the variable which holds the value from browser -> if some one accesses the uavariable lets say a opc ua client it will return the value of the variable written from the websocket
Ok, first thing, I can now write on especific node id. using this code:
//##########################################################################################
let val = await session.read({nodeId: "ns=4;i=83"})
console.log("Antes de escrever: ", val.value.value)
dataToWrite = {
//dataType: "Int32",
//value: 25
dataType: "Boolean",
value: true
}
let risultato = await session.writeSingleNode("ns=4;i=83", dataToWrite)
console.log("Depois de escrever: ", risultato)
val = await session.read({nodeId: "ns=4;i=83"})
console.log("Ler valor do node id :", val.value.value)`
//##########################################################################################
But what I want is, when I press this button, I want to send the value true no node id:
I used the code bellow, but dont work, I but the code inside an async function, because, if I dont use inside gime me an error, but anyway, it doesn´t work this way:
io.on('connection', function(client) {
client.on('B_Stop_OP_BSF_Pressionado', function() {
console.log("BOTÃO PRESSIONADO -> App");
writevariable;
});
});
async function writevariable() {
let val = await session.read({nodeId: "ns=4;i=83"})
console.log("Antes de escrever: ", val.value.value)
dataToWrite = {
dataType: "Boolean",
value: true
}
let risultato = await session.writeSingleNode("ns=4;i=83", dataToWrite)
console.log("Depois de escrever: ", risultato)
val = await session.read({nodeId: "ns=4;i=83"})
console.log("Ler valor do node id :", val.value.value)
console.log("Done");
}
Conclusion: I can write, but what I want is for me to click the button, and then call me the writevariable function.
is your http backend opc ua server? or client? i assume your events get lost because of open ends... its kind of hard to understand your code!
I am learning from scratch, and it's the first time working with node opcua and socket.io. I am using for my master's thesis. Sorry if it's hard for you to understand, in mid time I finally made it works.
html code:
app.js:
Webserver + OPC UA Server:
// Webserver Part
const express = require('express');
const app = express();
const http = require('http');
const server = http.createServer(app);
const { Server } = require("socket.io");
const io = new Server(server);
app.get('/', (req, res) => { res.sendFile(__dirname + '/index.html');});
let variable1 = 0;
io.on('connection', (socket) => {
socket.emit("hello")
console.log('a user connected');
socket.on('buttonClick', (data) => {
variable1 = variable1 + 1
console.log("buttonClick", variable1)
})
});
server.listen(3000, () => {
console.log('listening on *:3000');
});
// OPC UA Part -> Server
const { OPCUAServer, Variant, DataType, StatusCodes } = require("node-opcua");
(async () => {
const server = new OPCUAServer({
port: 4840,
resourcePath: "/UA",
});
await server.initialize();
console.log("initialized");
const addressSpace = server.engine.addressSpace;
const namespace = addressSpace.getOwnNamespace();
namespace.addVariable({
organizedBy: addressSpace.rootFolder.objects,
nodeId: "s=clickcount", // a string nodeID
browseName: "clickcount",
dataType: "Int32",
value: {
get: () => new Variant({ dataType: DataType.Int32, value: variable1})
}
});
server.start(function() {
console.log("Server is now listening ... ( press CTRL+C to stop)");
console.log("port ", server.endpoints[0].port);
const endpointUrl = server.endpoints[0].endpointDescriptions()[0].endpointUrl;
console.log(" the primary server endpoint url is ", endpointUrl);
});
})();
index.html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<button id="button1">Click Me!</button>
<script src="/socket.io/socket.io.js"></script>
<script>
const socket = io("http://127.0.0.1:3000/");
socket.on("connect", () => {
console.log("connected")
socket.on("hello", () => {
console.log("hello from backend")
})
const button1 = document.getElementById('button1');
button1.addEventListener('click', function(e) {
e.preventDefault();
console.log("clicked")
socket.emit('buttonClick');
});
})
</script>
</body>
</html>
