OPC UA

• ... for OPC UA the router has to be approve as “Trusted Client”, if an appropriate safety level is set on the OPC server

1. Open plug-in by clicking “OPC-UA Client” in the project configuration’s plug-in list.
2. Click the plus button or double click on the existing entry.
3. Specify access data. (chapter “Properties of OPC UA access data”).
4. Use the “Check connection” button to initialize a connection. If a corresponding safety level is set on the OPC server, the connection will fail. You must then release the OPC router on the OPC server as a trustworthy client. Reinitialize your OPC server, if necessary. Test again to verify successful connection setup.
5. Confirm with “OK”.

The OPC UA can now be used to define a connection.

Introduction to OPC UA

The OPC Unified Architecture (OPC UA) is a platform-independent communication standard designed to facilitate reliable data exchange between various devices and systems across different industries. It provides a flexible and scalable framework to enable interoperability through standard data models and communication protocols.

High-Level Capabilities in OPC Router

The OPC UA Client plugin within OPC Router acts as a key communication link between OPC UA servers and the various systems connected through OPC Router. This plugin, along with triggers and transfer objects, provides the following capabilities:

• Seamless Data Transfer: OPC UA enables both reading and writing of values between systems through its client-server model. The Transfer Objects in OPC Router make it possible to define how data is mapped between systems, allowing customized transformations and routing of information.
• Subscription Management: The plugin can create Subscriptions to monitor data changes or events efficiently, minimizing network load while ensuring systems receive timely updates.
• Trigger Mechanisms: Triggers in OPC Router can react to data changes, such as value updates or specific conditions. This allows for event-driven workflows where actions are initiated based on data from OPC UA servers.
• Security and Reliability: OPC UA is designed with built-in security features, including encryption, user authentication, and redundancy support. These features, managed via OPC Router's security settings, ensure that all communication remains safe and continuous, even in complex environments.

Configuration Overview

The OPC UA Client plugin connects OPC Router to all accessible OPC Servers. If an OPC Server runs on a different computer, the OPC Router must be approved as a "Trusted Client" if an appropriate safety level is set on the OPC server.

The operation is straightforward:

• Open the Plugin: Double-click "OPC UA Servers" to open the list of created OPC connections.
• Add or Edit Connections: Choose "Add new set as access data" or double-click an existing entry to edit.
• Specify Access Data: Enter the necessary access data (refer to the chapter "Properties of OPC UA access data").
• Check Connection: Use the "Check Connection" button to initialize a connection. If a corresponding safety level is set on the OPC server, the connection may fail. In this case, approve the OPC Router on the OPC server as a trusted client. Reinitialize your OPC server if necessary, and test again to verify successful connection setup.
• Confirm and Use: Confirm with "OK". The OPC server can now be used to define a connection.

opc_ua_plug_in.md

Overview of Triggers and Transfer Objects

Triggers and Transfer Objects are core components of OPC Router that facilitate efficient data management and workflow automation between connected systems.

Triggers Overview

Triggers are mechanisms that drive actions in response to specific conditions or events. They enable event-driven workflows, making it possible for OPC Router to respond immediately to data changes. Key types of triggers include:

• Threshold Trigger: Activates when a value crosses a specified threshold, which is useful for monitoring key performance indicators or critical values.
• Bit Trigger: Reacts to changes in specific bits within a data point, often used in scenarios where bit-level control or monitoring is required.
• DataChange Trigger (DC Trigger): These triggers activate when a data point in an OPC UA server changes, allowing workflows to react in real time to updated information.
• Multi DataChange Trigger: Monitors multiple data points and triggers actions when any of them change, providing more comprehensive monitoring capabilities.
• DataChange Missing Trigger: Used to detect when expected data changes are missing, which can be critical for ensuring timely updates in certain processes.
• Message Trigger: Reacts to messages received from the OPC UA server, often used for logging or notification purposes.
• OPC Event Trigger: Triggers actions in response to events from the OPC UA server, enabling event-driven workflows based on server-side occurrences.

Transfer Objects Overview

Transfer Objects (TOs) define how data flows between different sources and targets. They provide a structured way to map, transform, and transfer data efficiently within OPC Router's ecosystem.

• OPC Data Access Transfer Object: This Transfer Object allows OPC data points (nodes) to be read and written, providing basic data mapping and transfer capabilities between systems.
• Structured Transfer Object: Facilitates the handling of complex data structures, ensuring data is correctly mapped between systems that use structured or nested data formats.
• Message Transfer Object: Used for transferring message-based data, often applicable in scenarios where data is communicated in discrete messages rather than continuous values.
• Methods Transfer Object: Allows the invocation of methods on the OPC UA server, providing capabilities to execute server-side commands or functions as part of the data workflow.

Triggers and Transfer Objects work in tandem to create robust, automated data workflows that improve efficiency, reduce manual interventions, and enhance data consistency across interconnected systems.

Background Information from OPC UA Specifications

• Address Space Model: OPC UA's Address Space is fundamental for representing information. Nodes, such as variables and objects, create a structured and navigable representation of the data, allowing the OPC Router to easily interact with data in a meaningful way.
• Quality of Service (QoS): The quality of data values is crucial in industrial systems. Values are labeled as "Good", "Uncertain", or "Bad" based on their reliability. OPC Router uses these quality attributes to decide on data transfer, avoiding errors when values are deemed invalid.
• Security and Authentication: Security is integral to OPC UA, with multi-layer encryption and authentication protocols. OPC Router's Security Tab ensures that only authorized users and trusted certificates are used, preventing unauthorized access.
• Subscription Management: OPC UA subscriptions allow for efficient monitoring of data changes. This mechanism is particularly useful for applications requiring up-to-date information without the performance hit of continuous polling.

Use Cases

The OPC UA Client plugin is highly versatile, enabling a variety of use cases that demonstrate its importance for Industry 4.0 implementations and seamless data integration:

• OPC UA to Database Integration: PLCs control machine sequences and processes. For secure communication, we recommend using a trigger with a handshake mechanism, such as the Message Trigger or alternatively the Bit Trigger. When using the Message Trigger, the payload (i.e., the data) is provided along with the trigger, which can then call a stored procedure in a database. The response to the PLC can also be securely transmitted using the response functionality of the Message Trigger, ensuring reliable communication back to the controller. With the OPC UA Client plugin, production data can be read from the PLC via OPC UA, transformed, and stored in an SQL database. Conversely, database data can be sent back to the PLC to adjust production parameters based on customer-specific requirements.
• Edge Computing and Cloud Integration: The OPC UA Client plugin can act as an edge computing unit, connecting OPC data sources in local networks, buffering data, and subsequently transferring it to higher-level systems such as ERP or cloud platforms via protocols like MQTT. When the OPC UA Client is used with a publish interval and the DataChange Trigger, high-frequency data changes (e.g., every 5 ms) can be seamlessly transferred to systems like MQTT, InfluxDB, or Kafka. This allows for rapid data processing, with achievable rates of over 2000 value changes per minute. This setup is ideal for environments where on-premises data preprocessing is required before cloud transfer.
• Shopfloor Integration for Notifications: The Message Trigger within OPC Router ensures communication reliability by acknowledging messages from machines on the shopfloor. For example, when a pallet is completed, the OPC Router can send an acknowledgment back to the PLC, allowing the machine to proceed with the next task. Any error during processing can also trigger a message back to the PLC to stop production and prevent further issues.
• CSV Data Logging: OPC UA can be used to read process values and log them into a CSV file for historical analysis. When data changes, it is logged into an existing CSV file or a new one created. This is ideal for scenarios requiring simple data tracking without complex database dependencies.

Summary

The OPC UA Client plugin in OPC Router provides extensive tools for connecting to and managing OPC UA server data, ensuring secure and reliable communication. Triggers and Transfer Objects extend the capabilities by enabling dynamic, event-driven workflows and detailed control over data routing and transformation. Through its well-structured tabs, users can set up and customize every aspect of the OPC UA interaction, optimizing data flow for different operational needs.

For more detailed step-by-step instructions on individual tabs and options, refer to the specific setup guide for each part of the configuration.