OPC UA Read

This function block is designed to read values from an OPC UA (Open Platform Communications Unified Architecture) server. It allows users to connect to a specified node on the server and retrieve its value.

📥 Inputs

Client An OPC UA client instance that is used to connect to the OPC UA server.

Node Address The address of the specific node from which you want to read the value.

📤 Outputs

Value The output provides the current value of the specified node retrieved from the OPC UA server.

🕹️ Controls

This function block does not contain specific UI controls for direct interaction.

🎨 Features

Node Value Retrieval Connects to an OPC UA server and retrieves the value of a specified node, allowing for real-time data access.

Integration with Existing Systems Easily integrate with other systems that use OPC UA for communication.

📝 Usage Instructions

1. Connect Client: Link an active OPC UA client to the Client input.

2. Set Node Address: Enter the address of the node you want to read from in the Node Address input.

3. Evaluate: Run the block to read and retrieve the value from the specified node, which will be provided as output.

📊 Evaluation

When executed, this function block retrieves the current value from the specified OPC UA node, providing an easy way to access data from an external device or system that utilizes the OPC UA protocol.

💡 Tips and Tricks

Debugging Connection Issues

If you experience issues connecting to the OPC UA server, ensure that the client is properly configured and actively connected to the server. Check firewall settings and ensure that the server address is correct.

Validating Node Address

Ensure that the node address you provide is valid and exists on the OPC UA server. You can usually find this information in the server's documentation or management interface.

Handling Data Type Changes

If you expect the data type of the value being read to change, consider implementing error handling strategies to ensure your application can manage unexpected data types gracefully.

🛠️ Troubleshooting

Invalid Client Error

Ensure that the OPC UA client is initialized and correctly connected before passing it to this block. Check that the client is not None when evaluating.

Node Not Found

If the specified node address does not exist, ensure you are using the correct address format. Double-check the node address against the OPC UA server's namespace or explore the server using a tool compatible with OPC UA.