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OPC UA Interface

Connect external systems to C-Gate data points through the OPC UA server.

Endpoint and Connection URL

The OPC UA server is available on C-Gate IoT Hub and also on the IoT Connector if enabled:

  • Address: C-Gate Hub or Connector address
  • Port: 4840
  • Typical endpoint URL: opc.tcp://<ip>:<port>

Examples:

opc.tcp://192.168.5.100:4840
opc.tcp://c-gate.my-company.com:4840

Tip

Make sure port 4840 is exposed in the docker compose file and firewall access on that port is permitted on the IoT Hub.

Hub and Connector Availability

OPC UA is available on both the C-Gate IoT Hub and the C-Gate IoT Connector. On the IoT Connector, OPC UA must be enabled in the connector settings. The OPC UA interface contains nodes provided by connected devices (for example QIROX robots and QINEO welding machines), as well as nodes provided by C-Gate. C-Gate-provided nodes depend on licensing. The detailed node set is documented in the separate document C-Gate Datapoints.

Authentication

The Authentication for the OPC UA Server can be configured in the C-Gate IoT Hub and Connector Settings View.

Info

If the Authentication is configured to use the C-Gate user credentials, a device login and pin is used for the login an needs to be set for the user account at the C-Gate IoT Hub.

Namespace and Data Point Structure

OPC UA exposes device data and C-Gate data in:

  • Namespace URI: urn:Cloos:CGate:APIv1

This namespace is often mapped to namespace index 2, but the index can differ between systems. Always rely on the namespace URI when browsing and validating nodes.

Only data points with access type current are exposed through OPC UA.

Node ID Composition

Each data point is addressed by a Node ID composed of:

  • Namespace: urn:Cloos:CGate:APIv1
  • Identifier pattern: APIv1/<DeviceId>/<DataPointId>

Example data point:

  • Robot Device ID: 0012345
  • Data point: OperatingMode

Resulting logical Node ID parts:

  • Index (namespace): urn:Cloos:CGate:APIv1
  • Identifier: APIv1/0012345/OperatingMode

Many OPC UA clients show this as a string node in one of these forms:

  • nsu=urn:Cloos:CGate:APIv1;s=APIv1/0012345/OperatingMode
  • ns=2;s=APIv1/0012345/OperatingMode (only if index 2 is assigned on that server)

Connect with UA Expert

Prerequisites

  • Network access from the UA Expert PC to the C-Gate IoT Hub Server or Connector Device
  • OPC UA endpoint reachable on port 4840

Step-by-step

  1. Open UA Expert.
  2. Open the server management window.

  3. Add a new server endpoint using:

    opc.tcp://<ip>:4840

  4. Connect to the server.

  5. Select the security policy and certificate trust settings required by your C-Gate deployment.
  6. In the address space, browse to namespace urn:Cloos:CGate:APIv1.
  7. Find the target node using the identifier pattern APIv1/<DeviceId>/<DataPointId>.
  8. Drag the variable to the Data Access View to monitor values.
  9. For writable data points, write a test value from Data Access View.

Warning

Write operations are only possible for data points that are writable in C-Gate (e.g. WriteVar).