OPC UA Server

Latest version: 4.0.19 build 520. May 20, 2020.

The OPC UA Server plugin exposes real-time data from our data loggers as standard OPC UA Data Access variables. It lets OPC UA clients connect to your existing logging system and read process values, device states, counters, and calculated parameters in a consistent and secure way. This page explains how the plugin works, how to configure it, and how to integrate it with your OPC UA client applications.

Download  | PDF manual

OPC UA (Unified Architecture) is a platform-independent protocol for machine to machine communication. It replaces classic OPC based on DCOM and removes dependency on the Windows COM stack. The OPC UA Server plugin follows the Data Access profile, which focuses on current values, quality flags, and timestamps. You can run your OPC UA clients on Windows, Linux, or macOS and connect to the server using standard OPC UA libraries.

The plugin runs as an OPC UA server instance hosted by the logger application. It subscribes to parser variables produced by the logging engine and exposes them as OPC UA nodes. Each parser variable becomes an OPC UA variable with attributes such as value, data type, timestamp, and quality. When new data arrives from a serial port or TCP connection, the logger updates the variable, and all subscribed OPC UA clients receive the new values. This allows you to reuse the same data flow for logging, visualization, and control system integration.

OPC UA Server endpoint and basic parameters

To connect an OPC client, you need the server URI, for example:

opc.tcp://WORKSTATION-AS23ND:10003

The plugin configuration defines several important properties:

• Name - the readable server name shown in your OPC UA client or OPC browser. For example, "Advanced Serial Data Logger OPC UA Server".
• Protect by password - optional authentication of client sessions. You can specify a login and password so only authorized OPC UA clients can connect.
• Set a bad quality for an item after X nulls - handling of invalid or missing data from the parser. When the parser plugin cannot decode input properly, it sets the parser variable to NULL. The OPC UA Server plugin can keep the last valid value but mark the quality as "Bad" after a configurable number of consecutive NULL values.
• Group tags - automatic grouping of variables into a simple hierarchy. You can group items by data source name (for example, COM1, COM2, 127.0.0.1) or by device ID, which makes browsing easier in large systems.

Integration with a logger (e.g, Advanced Serial Data Logger)

To integrate the OPC UA Server plugin with Advanced Serial Data Logger:

1. Install Advanced Serial Data Logger and configure a serial port, for example, COM1 with the correct baud rate and protocol.
2. Define a parser that extracts fields from incoming lines and sets parser variables such as DATE_TIME_STAMP, TEMP_C, and STATUS.
3. Install and enable the OPC UA Server plugin in the logger configuration.
4. Set a server name, and optionally enable password protection.
5. Configure tag grouping, for example by port name or device ID.
6. Start logging and then connect with your OPC UA client to the server URI (e.g., opc.tcp://192.168.1.3:10003), browse and read values.

Incoming serial line (COM1):

2025-01-02 08:00:00;DEVICE01;25.6;OK

Parsed variables:

DATE_TIME_STAMP = 2025-01-02 08:00:00
DEVICE_ID       = "DEVICE01"
TEMP_C          = 25.6
STATUS          = "OK"

OPC UA Data Access:

Node       = COM1/DEVICE01/TEMP_C
Value      = 25.6
DataType   = Double
Timestamp  = 2025-01-02 08:00:00
Quality    = Good

Key features

• Standard OPC UA Data Access interface that exposes logger parser variables.
• Communication without reliance on DCOM. Compatible with OPC UA clients on Windows, Linux, and macOS.
• Flexible tag organization using group tags by data source name or device ID to build a clear hierarchy for browsing.
• Supports dynamic adding of OPC tags.
• Configurable quality handling with consecutive NULL values.
• Client and subscription monitoring through the "Active clients" view, which simplifies diagnostics and commissioning.

Summary

The OPC UA Server plugin extends our loggers with a well-supported industrial interface for control, analytics, and visualization systems. By exporing parsed variables directly to OPC UA Data Access nodes, it reduces integration work and improves data consistency between your data logging system, SCADA, and other industrial applications.

Download  | PDF manual

How to enable this plugin

The figure below shows how to select the plugin on the "Modules" page.

How to configure the plugin

The figure below shows how to configure the plugin. Please, look at the documentation for the full description of all settings.