Node-Red-OPCuaServer-UR

This flow brings data from a Universal robot via Modbus TCP to a Dashboard. This data is then send to a Node-Red OPC UA server and can be access via an OPC UA client.

Tested Node-red Version

• 2.0.6

Requied Node-red nodes:

• node-red-contrib-opcua-server
• node-red-contrib-bitunloader
• node-red-dashboard
• node-red-contrib-modbus
• node-red-contrib-ui-artless-gauge

A overview of the Node-red flow - Modbus

The data is send from this flow to the OPC-UA flow

A overview of the Node-red flow - OPC UA

How to setup

OPC UA is a machine to machine communication protocol for industrial automation - It gives a posiblility to communicate both vertically and horizontally in an industrial setting.

Modbus can be used for a wide variety of equitment. Here it is used as a data provider. For simpel testing, I used URSim, an virtual mashine with the UR Polyscope software build in (It can be downloaded from Universal robots homepage) that runs a Modbus TCP Server.

REMEMBER TO CHANGE THE IP TO A MODBUS SERVER THAT HAVE RELEVANT DATA AVALIABLE

How to import the code

• Install Node-Red on your platform
• Install the Nodes
• Go to Import in the top corner

• Inset the code from the Node-Red Code
• Setup the Modbus server, this setup is made for the adresses of the FC3: Holding register that fits a Universal Robot.
• Setup the OPC UA server for your use case.
• Have some fun with the data :)

Change the pull from holding register

Making data ready for the server

The two function are sorting the data and putting it into an array, that are set to be a global variable.

Setting up the server

The OPC UA Compact server can be setup by dobble clicking on it.

When the data are avalible globally via the function blocks the servers adresse space can configurede. See the file: Node-Red Code\OPCUA-Compact-server-adress-space.json.

How to add a new data point to the server

1. Put the data as a global variable, here the variable are "isoOutput" and "IsoInput"

2. Open the server and edit the address space (From here the focus will be en the variable "isoInput").

• Set the variable to 0 ("isoInputs"): line 27

this.sandboxFlowContext.set("isoInputs", 0);					//change "isoInputs"

• Create the device ("Universal Robot"): line 45 - 47

const myDevice = namespace.addFolder(rootFolder.objects, {
"browseName": "Universal Robot"							//change "Universal Robot"
});

• Create the namespace ("Digital InputOutput"): line 49

const DigitalInputOutput = namespace.addFolder(myDevice, { "browseName": "Digital InputOutput" }); 	//change "Digital InputOutput

• place the variable on the namespace and name it ("isoInputs" and "Inputs"): line 50

const isoInputs = namespace.addFolder(DigitalInputOutput, {"browseName": "Inputs"});	//change "isoInputs" in the start and "Inputs" in the end

• configere the variable as a OPC UA object ("isoInputs", "Input", "s=Isolated_Input", "Double"): line 61 - 82

//Digital input
  const DigitalInput = namespace.addVariable({
    "organizedBy": isoInputs,							//change "isoInputs"
    "browseName": "Input",							//change "Input"
    "nodeId": "ns=1;s=Isolated_Input",						//change "Isolated_Input"
    "dataType": "Double",							//change "Double"
    "value": {
      "get": function() {
        return new Variant({
          "dataType": DataType.Double,
          "value": flexServerInternals.sandboxFlowContext.get("isoInput")	//change "IsoInput"
        });
      },
      "set": function(variant) {
        flexServerInternals.sandboxFlowContext.set(
          "isoInput",								//change "isoInput"
          parseFloat(variant.value)
        );
        return opcua.StatusCodes.Good;
      }
    }
  });

• configere a view on the server ("UR-Digital-Input-Output"): line 241 - 244

  const viewDIO = namespace.addView({
    "organizedBy": rootFolder.views,
    "browseName": "UR-Digital-Input-Output"					//change "UR-Digital-Input-Output"
 });

• add a reference to the view ("DigitalInput.nodeId": line 252 - 255

  viewDIO.addReference({
    "referenceType": "Organizes",
    "nodeId": DigitalInput.nodeId						//change "DigitalInput.nodeId"
  });

• deploy the Node-Red and wait for the server to light up green

• connect to the server via a client

Access data via OPC UA Client

To access the data on the server, use a OPC UA Client, here I use Unified Autoamtion UAExpert Client (It can be downloaded for free on they homepage)