OPC Data Client Development Toolkit

Rapid OPC UA, DA, A&E, XML-DA Client Application Creation


  • OPC Data Access (DA)
  • OPC Alarms & Events (A&E)
  • OPC UA Data Access/Generic Data
  • OPC UA Alarms & Conditions
  • OPC UA Complex Data
  • OPC UA PubSub
  • Compliance Tested & Certified
  • No-Code, Low-Code, & More
  • Developer Productivity
  • Browsing Dialogs & Controls
  • Specialized Client Objects
  • Connectivity Explorer
  • Excel Connector

Read and write real-time data using the OPC DA standard

Used for reading/writing of real-time data with OPC DA 1.x, 2.x, and 3.x servers connected to control system devices such as PLC, DCS, etc. devices such as PLC, DCS, etc.

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OPC DA Sample Application with Source Code


Access alarm and event notifications from OPC A&E Servers in your custom application

As supported by your OPC A&E server, access process alarms, operator actions, informational messages and tracking/auditing messages

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OPC Alarms and Events GetConditionState Example




Read and write real-time data using OPC Unified Architecture (UA) Generic Data Standards

In OPC UA, the functionality of classic OPC Data Access (DA) is called generic data.  OPC Data Client supports full read/write subscribe capabilities and more. 

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OPC UA Read Single Tag Value Example

Access Event Notifications, Alarm Acknowledgement and Condition Management in OPC UA Servers

OPC Data Client provides simple methods and event handlers provided to work with OPC UA servers that follow the Alarm & Condition Facet standards.

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OPC UA Alarms and Conditions Method calls

Access Complex Data Models in OPC UA from Your Application

The OPC UA specifications provide for means for industry organizations and users to define complex data models where a node is no longer just a single value. A node might be a structure, also known as a User Defined Type (UDT) containing multiple values of differing data types. 

OPC Data Client provides methods for reading, writing, and subscribing to complex data within an OPC UA Server.  The Siemens S7-1500 PLC is an example of a device that has a built in OPC UA server that supports UDTs or structures.

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What is OPC UA Complex Data


Deliver OPC UA datasets using message-oriented transports 

Part 14 of the OPC Unified Architecture adds the ability to deliver data sets using message-oriented middleware. Starting with Version 2019.2 (5.56) and higher of the OPC Data Client toolkit, these features are supported in the Ultimate Edition product license.

  • Subscribe to dataset messages with data or events from a publisher over UDP & MQTT transports with UADP and JSON message formats
  • Included OPC UA Demo Publisher helps you test your client application
  • Load and inspect PubSub configuration from a binary file, or access it live in an OPC UA server over its information model.

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OPC UA PubSub Conceptual Diagram

With thanks to Matthis Damm of AscoLab from his OPC Day presentation for the infographic

Connecting to non-Windows devices made before OPC UA

OPC XML-DA was a predecessor to OPC UA that was widely adopted in applications where OPC XML-DA servers were placed into devices that were to be connected over radio networks and non-Windows environments.  Wind turbines from Siemens and others are the most common device where OPC XML-DA servers are found. 

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OPC XML DA Example

Assuring Interoperability Through Real Testing

Software Toolbox was a Charter Member of the OPC Foundation, joining back in 1996 when the standards were still being written, because we believed in what standards could do for industrial automation. 

Throughout our history, we and our partners have remained committed to the process of OPC Interoperability Testing and OPC Compliance Testing.  The OPC Data Client is regularly tested at the OPC Foundation's OPC Interoperability Workshops and has passed their independent lab testing process. These processes involve testing the toolkit and it's reference samples against many different OPC servers from other vendors, and working together with those suppliers to insure our products work well together. 

OPC Data Client OPC Certification Logos



Different Approaches Deliver Choice for Your Application

Every application need is unique. If you were a carpenter, you would not use a hammer to insert a screw. We know development is no different, so OPC Data Client provides different development models for building your x86 and x64 applications.

  • Procedural/Imperative - you are in control. Whether you use our low-code methods or some of our more complex APIs, you write the code that calls methods on OPC Data client objects, passing in arguments, receiving results, and is the traditional natural way to many developers.  You have control, but it will take more code than the other development models. 
  • Live Binding - No-code also known as codeless development for binding the properties of visual or non-visual components to OPC data in Visual Studio
  • Live Mapping - create logical objects in your code, then annotate them with attributes that are connected to OPC Data
  • Reactive Programming - Microsoft Reactive Extensions allow you to produce event-based programs with OPC client data streams and LINQ-style operators

Each model is complemented by our developer productivity features and extensive documentation and help. 


Reducing Time to Market and Total Cost of Ownership

We understand the job of being a developer and want to go beyond just providing a set of tools that reduces your need to know the details of the OPC specifications.  The OPC Data Client delivers productivity in several areas

  • Intellisense and Object Browser - XML comments with rich information about elements
  • Contextual help
  • ReSharper Annotations - on API members using attributes such as [CanBeNull] and [NotNull]. Annotations help ReSharper users catch improper usages early.
  • Visual Studio Design/Property Grid awareness
  • And the little details that make a difference
    • Use of FxCop Code Analysis rules in builds
    • Binary and XML serialization
    • Equality methods and operators where needed
    • Early argument checking
    • OPC Operations return a single type of exception to help you build robust applications

OPC Developer Productivity Tools Example

Ready-to-Use Tools for Delivering Your Customer Experience

Don't reinvent the wheel, we have the tools. Browsing for OPC servers and items is common functionality you should not have to build yourself.

OPC Data Client includes ready-to-use, rich UI browsing dialogs that do not need to be placed on a form. They can be called from your code and used. 

Browsing controls are intended to be placed on your UI form and adjust the visual appearance and behavior to integrate more closely with your applications.

Example OPC Browsing Dialogs and Controls

More Tools to Reduce Your Development Time and Cost

Working with OPC UA brings new concepts designed to aid in working with multiple OPC UA server applications and managing the certificate based trust and security provided by the standard. 

OPC Data Client provides several objects to help you avoid writing unnecessary code.

  • OPC UA Global Discovery Client
  • OPC UA Certificate Management Client
  • OPC UA Client Application Service

OPC UA Specialized Client Object Code Example

Testing target OPC Servers is Easy with Connectivity Explorer

The Connectivity Explorer application allows you to connect to and browse the data hierarchy of OPC Data Access and OPC Unified Architecture servers and data nodes. You can subscribe to data changes, and view the results live. With the optional Excel Add-On you can setup Excel Real Time Data (RTD) links to data. 

OPC Connectivity Explorer Helps Test OPC Clients and Servers

Real-Time Two-Way for OPC to Excel without Macros or Code

This separately licensed product from the OPC Data Client Developers Toolkit allows you to drag/drop or copy/paste values from the OPC Data Client Connectivity Explorer into Excel 2007 to Current versions, desktop only. Web/browser run Excel is not supported. 

Data transfers are done using the Excel Real Time Data (RTD) function and do not require any programming, macros, or add-in software for Excel. 

This feature works with OPC DA, OPC XML-DA, and OPC UA Generic Data. 

Live OPC Data in Excel using Real Time Data (RTD) Extensions


  • Development Platforms
  • Development Languages
  • Operating Systems
  • Videos
  • Documentation & Release Notes
  • Sample Code
  • Internal Details
  • Learn about OPC

Full details for all versions are provided in our knowledgebase. Below is a high level of currently supported platforms for your x86 or x64 development.


  • Visual Studio 2022
  • PyCharm
  • .NET Framework 4.7.2 through 4.8.1
  • .NET 6, 7, & 8

Linux and macOS

  • .NET Core CLI Tools
  • JetBrains Rider
  • Visual Studio 2022
  • Visual Studio Code (with C# extension)
  • PyCharm
  • .NET 6, 7, & 8

OPC Data Client is specifically designed with broad development language support in mind, allowing you to develop an OPC client in a wide range of languages.
Click for full development language details

.NET Development
  • C#
  • Visual Basic
  • Python.NET
  • F#
  • LINQPad

COM development -  including but not limited to:

  • C/C++
  • VBScript (ASP or Windows Script Host)
  • Jscript
  • PHP and more

Most OPC client development is done on Windows, using .NET Core, .NET Standard, or .NET Framework.  Current supported platforms and .NET versions are detailed in our knowledgebase however here is a high level list.


  • Windows 10 (x86 or x64)  version 1809 - 22H2
  • Windows 11 (x64) version 21H2 - 23H2
  • Windows Server 2016 and 2016 Core (x64)
  • Windows Server 2019 and 2019 Core (x64)
  • Windows Server 2022 (x64)


We know that sometimes it helps to see someone showing you how to do things.  We have a wide range of videos available for the OPC Data Client product from short how to videos to detailed on-demand webinars. 

OPC Client Development Training Videos List

OPC Data Client documentation is all available online for review.  Documentation includes coverage of how to get started, development models, method calls, extensive sample code, best practices, troubleshooting, and more.

Click to view the online documentation      Click for current and past release notes 

OPC Client Development Online Documentation

There are over 150 source code examples across multiple development languages included in the online product documentation, and samples are also available for download in our knowledgebase

OPC Data Client Read Array Tags Code Sample

With any development tool, there are many details that you may be interested in learning more about. In addition to our online documentation, these are some of the more common areas of interest.

For .NET Standard OPC UA, uses OPC Foundation's OPC UA .Net Standard Library 1.4.360.33

For .NET Framework OPC UA, uses OPC Foundation UA-.NET-Legacy libraries as of March 25, 2020

Development is possible for x86 or x64 applications, full details under "64-bit platforms" in the product documentation.

If you have a technical question you have not been able to find an answer to yet, please contact our support team and they will work to answer your question, even before you have purchased any licenses.

A Beginners Guide to OPC Document CoverWe provide a variety of resources to help you learn more about the various OPC standards, how they work, and more. 



Robot Arm

I have to say, you have by far the quickest and best technical support of any company I’ve dealt with.  The .NET tools you offer are also the best I’ve found.  Great Job!

- Bob Miller, Developer

user image

“I came across OPC Data Client undertaking a C# project that needs to access data in a Siemens PLC using OPC.  Having used the free trial version, it quickly became clear that the OPC Data Client would remove the need for an in-depth knowledge of OPC client to server protocols and would alow me to concentrate on the application itself. It is very robust, easy to integrate into a .NET project and the response to my questions by email was excellent.  I’d certain only recommend the product and the company”.

- Peter Thomas, Control Specialists Ltd


I tell you this OPC Data Client is a great tool. I am a maintenance Manager responsible for a lot of equipment throughout our facility.  The OPC Data Client has allowed me to access equipment information with the click of a button anywhere onsite, corporate wide, or even from home.  I no longer have to wait on reports or track them down; I can see what’s going on with critical equipment by logging into our maintenance website.  This product has already paid for itself, Thanks again for the tools and your support!

- Rob Barnett, Nursery Supplies Inc.

Get Started Now

The demo is the full product. Once the OPC Data Client is connected to an OPC Server, it will run for 30 minutes at a time. The 30–minute timer will be disabled after 210 days from the initial version release.

Connect with Us

1-888-665-3678 (US + Canada toll free)
+1-704-849-2773 (Global)