When industrial control systems generate alarms and events across multiple OPC sources, how do you consolidate, view, and act on that data without being locked into proprietary tools? The OPC UA Alarms and Conditions (A&C) specification provides a standardized framework for collecting, routing, and managing this data — and OPC Expert implements it fully.

Webcast Summery

OPC Alarms and Conditions is the OPC specification that defines how alarms, conditions, and events are structured and communicated between producers — such as PLCs, DCSs, and RTUs — and consumers like historians and HMIs. Unlike proprietary alarm subsystems built into individual HMIs, OPC A&C enables structured alarm data to be captured in its entirety and routed to any destination without being disassembled or reformatted. OPC Expert implements the full A&C specification alongside OPC UA DA, OPC Classic, and MQTT, making it possible to work with alarm data from virtually any OPC-compliant source.

Key capabilities covered by the OPC A&C specification as implemented in OPC Expert:

  • Structured alarm data handling — captures the complete alarm or condition record as defined by the A&C spec, preserving all fields rather than extracting only partial values
  • Multi-server aggregation — connects simultaneously to multiple OPC UA A&C and OPC Classic servers, consolidating alarms from different sources into a single view
  • Real-time alarm monitoring — displays live severity changes, alarm states, and condition updates as they arrive from the OPC server, with acknowledgement and comment support built in
  • Protocol bridging — converts between OPC UA A&C, OPC DA, and OPC UA DA in any direction, enabling alarm data to flow across mixed-protocol environments
  • Alarm state support — handles the full range of OPC A&C states including high, high-high, low, low-low, shelved, suppressed, and adaptive alarms tied to dynamic limit values
  • Report-by-exception archiving — logs alarm records to SQL, cloud databases, or flat files only when a state change occurs, consistent with the event-driven nature of the A&C specification

The OPC Alarms and Conditions specification exists to bring structure and interoperability to industrial alarm management — OPC Expert puts that specification to work.

Introduction

Welcome to this live presentation on OPC Alarms and Conditions, where we explain how to collect and use OPC UA alarms and conditions — also known as OPC UA A&C. Today we’ll be covering the problem we need to solve, OPC UA alarms and conditions, their requirements, and how OPC Expert handles them. We’ll walk through the architecture and finish with a live demonstration. At the end, you’ll receive a link to this webinar recording as well as quick setup videos.

The Problem We Need to Solve

OPC servers generate many system alarms, conditions, and events. Human machine interfaces and historians need to access, capture, and handle this structured data. Users want to be able to view, acknowledge, archive, and analyze these alarms and conditions. The core question is: how exactly do we get alarms, conditions, and events out of our control system?

Architecture Overview

Here’s where we’re going. We start with a controller — any controller — and OPC Expert receives data from it via an OPC server. This can be OPC UA, OPC Classic (OPC DA), OPC Alarms and Conditions, or OPC Alarms and Events. Once OPC Expert receives that data, it forwards it to a remote computer running a database, and the results can be viewed in a browser.

Specifically, we will:

  • View real-time alarms and conditions inside OPC Expert
  • Capture those alarms and conditions and send them to a remote Microsoft SQL Server database
  • View the historical alarms and conditions to confirm data is being captured
  • Send the data to a browser via web service and view real-time alarms and conditions there
  • Configure alarms and conditions through the browser interface

Keep in mind that data flows from the OPC server to the database via a store-and-forward mechanism, and from OPC Expert to the browser via a web service.

Producers and Consumers

Event producers — PLCs, DCS systems, RTUs, and similar control systems — generate real-time data such as temperatures, flows, pressures, and currents. They sometimes create their own alarms, conditions, and events, but not always. In some cases you need to create those events yourself, and some systems have proprietary tools to view them.

On the consumer side, human machine interfaces and historians consume this data. They can also create their own alarms and events, but they typically do so by taking real-time data and generating events from it — they don’t usually consume ready-made structured alarms and conditions from a remote OPC A&C server.

What users really want is to consolidate data from many different systems into one place — and to consume structured data as-is, without having to recreate alarms they’ve already received.

The OPC Expert Alarm Gateway

In previous webinars we covered OPC to MQTT, OPC to Excel, tunneling, web pages, and the security gateway. In this webinar, we’re focusing on the alarm gateway. It provides the ability to consolidate data from multiple different sources into one system. It’s entirely standards-based — OPC in, OPC out — and it can both create structured alarm data and consume structured alarm data without altering its structure.

The OPC Expert alarm gateway connects to an OPC server and uses whatever security that server provides — OPC Security or Windows Security — and can add its own security on top. This is the same security gateway capability discussed in the previous webinar.

Platform Support

On the server side, OPC Expert runs on Windows XP through Windows 11, and Windows Server 2003 through Windows Server 2025. It includes support for both OPC UA and OPC Classic. It runs as a Windows service, meaning it starts automatically when the computer boots — no user login required. Data collection begins immediately, and acknowledgements can be forwarded back to the source as well.

All communication is handled through a single port — one port in, one port out — which makes it straightforward to manage from a firewall and security perspective.

Modules Inside OPC Expert

OPC Expert includes an Alarms and Conditions Events client that feeds into an intelligent engine, which can then output data via a web server or OPC UA server. It also includes a built-in converter supporting DA to UA, alarms and events to OPC UA A&C, UA to DA, and UA to web server — all conversions are built into the software.

Additional modules include:

  • A built-in MQTT broker, publisher, and subscriber
  • Database output to SQL (MySQL or Microsoft SQL), Amazon, Microsoft Azure, or local CSV
  • OPC history support — OPC UA HA, OPC Classic HDA
  • Excel output via RTD

In this webinar, we’re specifically focusing on the SQL module, the web server, the alarms client, and the UA server.

Extended Architecture: Clients and Platforms

OPC servers send data to OPC Expert, which can serve it to UA clients directly, or convert it to DA for legacy DA clients. For mobile apps or browser-based access, OPC Expert exposes a web service that works with phones, tablets, or any device — iOS, Android, or otherwise. For non-Windows platforms, you can access all of this data via web services using Python, JavaScript, C, or any scripting or compiled language you prefer.

Live Demonstration

For the demonstration we are simulating a controller. OPC Expert connects to it via an OPC server — specifically, a QuickStarts Alarms and Conditions server (an OPC A&C server) and a Kepware server (a DA server). We’ll walk through each stage: viewing real-time data in OPC Expert, archiving to SQL, viewing historical data, and then using the browser interface.

Connecting to the OPC A&C Server

After starting OPC Expert, browsing shows four OPC Classic servers and three OPC UA servers — including the Kepware UA server, the QuickStarts server, and the OPC Expert UA server. Connecting to the OPC UA Alarms and Conditions server and selecting Monitor immediately shows a live stream of events — severity, changes, type, and other condition fields. Any condition can be acknowledged directly from this viewer, right inside OPC Expert.

Archiving to Microsoft SQL Server

To archive the data, right-click the OPC UA Alarms and Conditions source and choose Archive OPC UA A&C. Output options include Amazon, CSV, Azure, Microsoft SQL, MongoDB, MQTT, and more. Selecting Microsoft SQL Server and pointing it at the remote SQL host (in this case, a machine called “sql-db”) and testing the connection confirms connectivity. Once applied, OPC Expert begins forwarding data immediately.

Over on the SQL Server Management Studio machine, refreshing the history database reveals a new table — Historical Data A&C — that grows in real time. Each alarm and condition appears as its own row, with all structured fields broken out into individual columns. Executing the query repeatedly shows the row count climbing steadily: 233, 257, 263, 385, 517, 527 rows — clearly accumulating. This same data can go to MySQL, MongoDB, Azure, or any other supported destination.

Setting Up the Web Service

To enable browser access, go to Tools > Servers and Services and enable the web server. This launches two Windows services: OPC Expert UA Server and OPC Expert Web Server. Both run under the system account and persist even after the OPC Expert GUI is closed. The system tray helper is optional — the services keep running regardless.

Viewing and Configuring Alarms in the Browser

Opening a browser reveals the built-in HMI, which includes visualization panels — instruments showing temperature and level, moving in real time. Switching to the Alarms and Conditions tab shows live events streaming in. These tabs work in any browser: Chrome, Edge, or others.

Raising the instrument value in the HMI immediately produces a high alarm in the A&C tab. Acknowledging it removes it from the view. Similarly, as the level value climbs, a high-high alarm fires when it reaches 40,000 — the current value and the threshold that triggered the condition are both visible. Acknowledging an inactive alarm removes it from the display.

Switching from the Viewer tab to Configuration, then navigating to Root > PLC, shows the level alarm definition. Editing it allows you to adjust thresholds directly — for example, setting High to 30,000, High High to 28,000, Low to 10,000, Low Low to 5,000, and dead bands to 100. Applying the changes takes effect immediately. The source node shown is the Kepware DA server — meaning OPC Expert is taking OPC DA data and generating its own alarms and conditions from it, because the original server didn’t provide them.

Even killing the services from Task Manager demonstrates the service model: Windows restarts them automatically because they are registered as services. The viewer reloads and resumes exactly where it left off.

Summary

In this demonstration we covered all four stages of the workflow:

  • Viewing real-time alarms and conditions inside OPC Expert
  • Archiving to Microsoft SQL Server and verifying the data is growing
  • Viewing historical alarms and conditions in SQL
  • Viewing and configuring real-time alarms and conditions through the browser

You can download OPC Expert and follow this same workflow yourself. A recording of this webinar and download links will be sent to you by email. If you’d like to explore further, Insight Works has separate webinars on OPC to web, archiving, tunneling, bridging, and trending — all available on our website at opcti.com.

Training

If you want to go deeper, Insight Works offers live, remote, hands-on training sessions where you can earn your Certified OPC Professional designation. In these workshops you configure DCOM, OPC security, firewalls, and more — working with a dedicated pair of computers, one as client and one as server. The format is interactive: instructors give you problems to solve, and once you’ve solved them, they break something new. It’s an effective way to build solid troubleshooting skills.

Classes are public and fully remote with a live instructor — no travel required. Private sessions for teams are also available, as are on-site options. For dates and details, visit opcti.com.

Questions and Answers

Questions submitted during the webinar will be addressed in the Q&A session that follows. A recording of the full session, including Q&A, will be emailed to all attendees along with a link to download OPC Expert and alarm and condition examples.