OPC UA client and server with a simple graphical interface for Node-RED.

This package provides a simplified, highly parameterized set of nodes to establish OPC UA Servers and Clients in Node-RED without complex coding.

Features Overview

• Dynamic OPC UA Address Space: Build hierarchical folders, objects, variables, and alarms dynamically from a visual tree editor or JSON.
• IPC Process Separation: Server runtime runs in a child process, preventing heavy OPC UA operations from blocking the main Node-RED event loop.
• Rich Node-RED Integration: Support for reading, writing, subscribing, calling methods, and managing sessions directly in Node-RED flows.

Server Functionalities

The server implementation consists of two nodes: opc-ua-server (the server runtime) and opcua-server-io (the data input/output node).

1. OPC UA Server (opc-ua-server)

This node instantiates the OPC UA Server process.

• Visual Tree Editor: Build folders, variables, custom objects, ObjectTypes (templates), alarms, methods, and enumerations visually.
• Dynamic Address Space: Rebuild the address space at runtime by passing a new JSON tree configuration in msg.payload.
• Authentication & Authorization: Configure users, groups, and comma-separated access permissions for folders, variables, and methods.
• Security Policies: Supports multiple security policies (None, Basic256Sha256, Aes128_Sha256_RsaOaep, etc.) and security modes (None, Sign, SignAndEncrypt).
• Certificate Management: Manage trusted/rejected client certificates.

2. Server I/O Node (opcua-server-io)

Interacts with an active local server instance. It supports the following modes:

• Read: Read values from server variables using a tag path or NodeId.
• Write: Write values to server variables.
• Event: Fire custom OPC UA events on target nodes.
• Events: Stream variable read, write, and alarm events.
• Status: Monitor server variable status snapshots.
• Active Alarms: Query active alarms on the server.
• Get Sessions: Retrieve active OPC UA client sessions.
• Delete Sessions: Forcefully close specific active sessions by ID.
• Method Input / Output: Route OPC UA method calls from clients into Node-RED flows and return output results.

Supported Variable Data Types, Arrays & Matrices

The server supports the following standard OPC UA data types, including arrays and matrices:

• Integers: Int16, UInt16, Int32, UInt32, Int64
• Floats: Float
• Others: Boolean, String, ByteString
• Arrays (1D): Pass standard JavaScript arrays or JSON arrays as values (e.g., [1, 2, 3, 4] or "[1, 2, 3, 4]").
• Multi-Dimensional Arrays (Matrices): Pass nested arrays. The dimensions are automatically detected based on the shape (e.g., [[1, 2], [3, 4]] is registered as a 2x2 matrix with dimensions [2, 2], and [[[1, 2], [3, 4]], [[5, 6], [7, 8]]] as a 2x2x2 matrix).

Note on 64-bit Integers (Int64/UInt64):

• Scalars are represented as [high, low] arrays (e.g., [0, 100] for the value 100).
• Arrays of 64-bit integers are represented as arrays of doublets (e.g., [[0, 100], [0, 200]]).
• They are handled internally using JavaScript BigInt.

Client Functionalities

The client implementation consists of opcua-client-config (shared connection configuration) and opcua-client (the action node).

1. Client Connection Config (opcua-client-config)

Manages connection configuration to an external OPC UA server.

• Connection Strategy: Limit reconnect retries to fail fast when servers are offline.
• Authentication: Supports anonymous or username/password authentication.
• Session Caching: Caches and reuse client sessions and method definitions.
• Address Space Browser: Provides an endpoint for browsing the server address space directly in the Node-RED editor.

2. OPC UA Client (opcua-client)

Performs actions on the configured OPC UA server. It operates in the following modes:

• Read: Batch read selected variables.
• Write: Batch write values with automatic type resolution.
• Browse: Browse child nodes of one or more node paths.
• Browse Recursive: Recursively search all nodes starting from specified NodeIds, returning resolved type definitions, values, descriptions, and method arguments in optimized batched reads.
• Method: Call OPC UA methods on the server.
• Subscription: Subscribe to variable value updates (minimum 50ms sampling/publishing).
• Events: Subscribe to OPC UA events.

Editor Interfaces

Server Editor

Client Editor

Support the Project

If you find this project useful, please support its development:

@vitormnm