create variable in Kepserver with node-opcua
<p>I have a Siemens 1200 PLC. Using <code>node-opcua</code> client and Kepserver I am able to read the variables and to change the values. 
Now I would like to create a new variable in the PLC from node-opcua in KepServer.
<a href="https://i.stack.imgur.com/Wq2lM.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/Wq2lM.jpg" alt="enter image description here"></a></p>

<p>I've tried to use node-opcua server because in the examples I've seen how to create variables, but I get an error because I am trying to connect to the same port that KepServer does.</p>

<pre><code>var server = new opcua.OPCUAServer({
    port: 49320, // the port of the listening socket of the server
    resourcePath: "", // this path will be added to the endpoint resource name
     buildInfo : {
        productName: "MySampleServer1",
        buildNumber: "7658",
        buildDate: new Date(2014,5,2)
    }
});
</code></pre>

<p><a href="https://i.stack.imgur.com/7a5t9.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/7a5t9.jpg" alt="enter image description here"></a></p>

<p>How could I deal to create a new variable? and to create a group tag from node-opcua?</p>

<p>Is it possible to have a opcua server in Kepserver and create variables connecting to that server directly?
My Kepserver is in: opc.tcp://localhost:49320
To connect to this Kepserver I use the nodeopcua client:</p>

<pre><code>var opcua = require("node-opcua");
var client = new opcua.OPCUAClient();
var endpointUrl = "opc.tcp://127.0.0.1:49320";
var the_session = null;
async.series([


    // step 1 : connect to
    function(callback)  {

        client.connect(endpointUrl,function (err) {

            if(err) {
                console.log(" cannot connect to endpoint :" , endpointUrl );
            } else {
                console.log("connected !");
            }
            callback(err);
        });
    },
    // step 2 : createSession
    function(callback) {
        client.createSession( function(err,session) {
            if(!err) {
                the_session = session;
            }
            callback(err);
        });

    },
    // step 3 : browse
    function(callback) {

        the_session.browse("RootFolder", function(err,browse_result,diagnostics){
            if(!err) {
                browse_result[0].references.forEach(function(reference) {
                    console.log( reference.browseName);
                });
            }
            callback(err);
        });
    },
    // step 4 : read a variable
    function(callback) {
        the_session.readVariableValue("ns=2;s=S7.1200.nombre", function(err,dataValue) {
            if (!err) {
                console.log(" temperature = " , dataValue.toString());
            }
            callback(err);
        })
    },

    // step 5: install a subscription and monitored item
    //
    // -----------------------------------------
    // create subscription
    function(callback) {

        the_subscription=new opcua.ClientSubscription(the_session,{
            requestedPublishingInterval: 1000,
            requestedLifetimeCount: 10,
            requestedMaxKeepAliveCount: 200,
            maxNotificationsPerPublish: 10,
            publishingEnabled: true,
            priority: 10
        });
        the_subscription.on("started",function(){
            console.log("subscription started for 2 seconds - subscriptionId=",the_subscription.subscriptionId);
        }).on("keepalive",function(){
            console.log("keepalive");
        }).on("terminated",function(){
            callback();
        });
        setTimeout(function(){
            the_subscription.terminate();
        },100000);


        // install monitored item
        //
        var monitoredItem  = the_subscription.monitor({
            nodeId: opcua.resolveNodeId("ns=2;s=S7.1200.nombre"),
            attributeId: 13
          //, dataEncoding: { namespaceIndex: 0, name:null }
        },
        { 
            samplingInterval: 100,
            discardOldest: true,
            queueSize: 10 
        });
        console.log("-------------------------------------");

        // subscription.on("item_added",function(monitoredItem){
        //xx monitoredItem.on("initialized",function(){ });
        //xx monitoredItem.on("terminated",function(value){ });


        monitoredItem.on("changed",function(value){
           console.log(" New Value = ",value.toString());
        });

    },

    // ------------------------------------------------
    // closing session
    //
    function(callback) {
        console.log(" closing session");
        the_session.close(function(err){

            console.log(" session closed");
            callback();
        });
    },


],
    function(err) {
        if (err) {
            console.log(" failure ",err);
        } else {
            console.log("done!")
        }
        client.disconnect(function(){});
});
</code></pre>

<p>I would like to create new variables from code in my Kepserver. I've seen that with the nodeopcua server code there's a way of creating variables: 
<a href="https://github.com/node-opcua/node-opcua/blob/master/documentation/creating_a_server.md" rel="noreferrer">Creating a Simple Server</a></p>

<p>I would like to use something such as in KepServer:</p>

<pre><code>server.engine.addressSpace.addVariable
</code></pre>

<p>What could I do to solve my problem?</p>