OPC?
Based on Microsoft’s OLE (now ActiveX),COM (component object model) and DCOM (distributed component object model) technologies, OPC consists of a standard set of interfaces, properties, and methods for use in process-control and manufacturing-automation applications.The
ActiveX/COM technologies define how individual software components can interact and share data. Backed by Microsoft’s NT technology, OPC provides a common interface for communicating with diverse process-control devices, regardless of the controlling software or devices in the process. The goal of the standard is Plug-and-Play, a concept developed by Microsoft and a number of other companies a few years ago. By using a standard way of configuring computer hardware (and software interfaces) automatically, a device will easily connect to another and immediately work without the need for lengthy installation procedures or complex configuration. Instead of having to learn how to use 100 or more custom toolkits, users will only have to learn one set of tools, because all OPC drivers will work the same way. OPC’s purpose is to compel the automation industry suppliers to push all device drivers toward a standard form. Essentially, OPC defines a common interface that permits interface development work to be performed once and then easily reused.
The OPC standard requires hardware suppliers to provide front-line data collection and distribution. They are the most familiar with how to access the device’s internal data efficiently.These devices then
become OPC servers, providing data to OPC client applications consistently.Application developers can then write code in any language deemed appropriate.
OPC - History
OPC (OLE for Process Control) is an industry standard created with the collaboration of a number a leading worldwide automation and hardware software suppliers working in cooperation with Microsoft.The
organization that manages this standard is the OPC Foundation.The Foundation has over 150 members from around the world, including nearly all of the world’s major providers of control systems,
instrumentation, and process control systems.The OPC Foundation’s forerunner — a task force composed of Fisher-Rosemount, Rockwell Software, Opto 22, Intellution, and Intuitive Technology — was able to develop a basic,workable, OPC specification after only a single year’s work. A simplified, stage-one solution was released in August 1996.
The objective of the OPC Foundation is to develop an open, flexible, plug-and-play standard that allows end users to enjoy a greater choice of solutions, as well as sharply reducing development and maintenance costs for hardware and software suppliers. The OPC Foundation has been able to work more quickly than many other standards groups because OPC Foundation is simply building on an existing Microsoft standard. Other groups which have had to
define the standards “from the ground up” have had a more difficult time reaching consensus as a result of the scope of their work.
Microsoft is a member of the OPC Foundation and has given strong backing to the organization. However, Microsoft has been careful to remain in the background and let the member companies with direct industry experience guide the organization’s work.
One of the most valuable aspects of Microsoft’s participation is the fact that it hosts an annual OPC Foundation meeting in Redmond,Washington (Microsoft Headquarters) to provide Foundation Members with a preview of coming developments in OLE/COM and other Microsoft technologies. Many Foundation Members are small companies and would not receive that kind of briefing from Microsoft if they were not Foundation Members.
End-Users are encouraged to join OPC Foundation, and several manufacturers actively participate in the specification and technical review process. Both End - Users and Automation Suppliers benefit from having a standard. For every automation system installed today,
there is a significant amount of time and money spent on integration. OPC ensures that automation systems can share information and interoperate with other automation and business systems across their plant or factory.
OPC - What is it?
Free OPC Software
 Automation Media is dedicated to develop the awareness and understanding about interoperability in automation by providing best information about open specifications that standardize the communication of acquired process data, alarm and event records, historical data, and batch data to multi-vendor enterprise systems and between production devices. Production devices include sensors, instruments, PLCs, RTUs, DCSs, HMIs, historians, trending subsystems, alarm subsystems, and more as used in the process industry, manufacturing, and in acquiring and transporting oil, gas, and minerals. |
| Supplier | Product | Notes |
| OPC Explorer | Popular free OPC client used for testing. Comprehensive features, very easy to use. Sponsored Link | |
| OPCX DA | Demo version of an ActiveX control which aims to simplify Data Access client development. | |
| Free Tools | Advosol offers a number of test and sample clients, usually as part of a toolkit or component evaluation (requires registration). Supported specifications include DA 2, DA 3, AE, HDA and XML-DA. | |
| Oxalis | HDA client providing graphical visualization of historical data. HDA server access ceases after 30 minutes in demo version. | |
| Trend Historian, | Evaluation versions of Canary Labs' trending and logging utilities. Updated versions include OPC Historical Data Access support: HDA server in Trend Historian, client in Trend Link. | |
| OPC DataHub | Time-limited demo of DA 2 and DA 3 server and client combination that supports OPC tunnelling, aggregation, and bridging. Also offers TCP and DDE client and server, plus scripted read/write connections to ODBC databases and MATLAB. | |
| U.C.ME-OPC | Client software for alarm notification and remote control, using a variety of wired, wireless and mobile technologies. Demo download runs for one hour before requiring restart, but otherwise unrestricted. | |
| TopView for OPC | Evaluation download of DA 2.05 client, allowing OPC tags to be monitored for user-configured alarm conditions. Notifications may be sent by email, pager or cell phone. Voice annunciation and text-to-speech allow delivery of audible alarm messages by phone or through the computer's speakers. A Remote Viewer option allows TopView instances to be remotely monitored from a Desktop PC or Windows Mobile device. | |
| OPC Test Client | Simple test client, originally intended for checking compatibility of servers with the company's PID tuning product. | |
| OPC Data Access Object | ActiveX control. Allows limited use of custom OPC interfaces from VB client. | |
| OPC DataSpy | Client for diagnostics and monitoring. Supports local and remote connections to DA and AE servers, and includes useful features such as a log of OPC calls. Slightly marred by an HMI which is counter-intuitive in parts. | |
| OPC Enabled ActiveX Controls | Gauge, Switch and Vessel controls are available, allowing connection to any OPC data source. | |
| Quick Data | Free DA client based on the same company's Local IO product. Includes facilities for buffering, scaling and masking of tag values. Requires .NET Framework 1.1. | |
| OPC DA Explorer, | Free GUI clients offering simultaneous connection to multiple servers. | |
| IOServer | Evaluation version of an OPC server which also includes client functionality. See servers for more details. | |
| Freeware clients | A range of easy freeware clients for DA, AE and HDA, plus an XML-DA test client. | |
| dOPC Explorer | Easy to use and attractive DA and XML-DA diagnostic client, including basic trend charts. Now supports DA 3 and XML-DA 1.01. Free for non-commercial use. | |
| KEPServerEX | Demo server download (see servers) includes simple yet elegant OPC Quick Client. | |
| LinkMaster | Demo version of comprehensive bridging product. Able to act both as OPC client and server, as well as DDE server. See also products from MatrikonOPC and Northern Dynamic. | |
| Operational Insight Lite | Free tool with a number of advanced capabilities, including trending and process mimics based on real-time and archived OPC data (DA and HDA). Requires periodic license renewal (free of charge) via Matrikon web site. | |
| new | HDA Explorer | Free tool for verifying historical data through HDA, testing HDA servers, and troubleshooting connectivity to HDA servers. |
| OPC Client for ODBC | OPC client which enables any ODBC-compliant database to exchange process data with an OPC server, using standard SQL queries. | |
| OPC Data Manager | 'Thin' OPC client which bridges between two OPC servers, taking data from one and writing it directly to the other. See also products from Kepware and Northern Dynamic. | |
| OPC Desktop Historian | Process Historian that collects and archives time-series process data, with reporting, analysis, and viewing facilities. Efficiently stores an unlimited amount of data and an unlimited number of tags. | |
| OPC Redundancy Broker | Enables easy implementation of redundancy in OPC-based systems, being designed for applications that must use redundant hardware and/or software to achieve a high degree of communication reliability. | |
| OPC Trender | Comprehensive yet easy to use trending tool. OPC DA is used to gather real-time data from any OPC server, while OPC HDA may also be used for historical data retrieval. | |
| OPC Explorer | Very simple GUI client for browsing available Data Access servers and items. | |
| Server Explorer | Powerful and easy to use test client. Connection Wizard allows a server connection with a group and multiple items to be established with just five mouse clicks. | |
| OPC Explorer | Demo version of a Data Access 2.0 diagnostic client. Allows live linking to other applications (e.g. Microsoft Excel) via a simple Copy and Paste operation, plus bridging between two servers. | |
| OPC Voyager | Visualization software for buildings and industrial plants. Free tester version has no time restriction, but is limited to 5 pages and 5 elements per page. | |
| Command-line Client | Powerful console client, supporting a full range of OPC DA operations. Great flexibility through ability to use pipes, plus CSV files as input/output. | |
| OPC Proxy | Gathers and caches data from multiple OPC servers in a networked environment. The data is then presented to client programs using simplified (non-OPC) COM interfaces. | |
| OPC Gateway | Enables data transfer between two OPC servers using only point and click or drag/drop configuration. Provides support for data transformations. Trial version is functionally unrestricted, but limited to 30 days use. See also products from Kepware and Matrikon. | |
| OPC DA Server Toolkit | A simple but effective OPC Browser utility is provided with Northern Dynamic's toolkit download. | |
| Delphi OPC Sample | Our own simple console client, written in Borland Delphi. Includes Delphi conversions of all published custom OPC interfaces. | |
| OPC for DB | Time-limited demo version of a Visual Basic application for bidirectional data transfer between databases and OPC servers. Source available at extra cost. | |
| OPC Browser, | Simple DA 2.0 (and 1.0) browser and client utilities. Data Access Client subscribes to the first 100 server tags it finds and continuously displays updates of their values. | |
| Prosys OPC Client | Simple DA client with source, demonstrating capabilities of the Prosys Sentrol rapid development framework. | |
| OPC Office Link | Greatly simplifies the task of importing live OPC data into Office applications (e.g. Excel) and ODBC databases. Free time-limited download available for evaluation. | |
| OPCEx | Provides an easy way to access real-time data from any OPC server via Microsoft Excel. Free trial download is available. | |
| OPC Test Client | Simple MDI application, with comprehensive support for the Data Access interfaces. | |
| OPC Demo Client | Flexible and easy to use client. One of our favorites. Version 4.10 adds integrated XML-DA support to the existing support for DA and AE. | |
| OPC console client | A simple console client, including source. Supports OPC Data Access 2. | |
| OPC Simulation server and GUI client | A simple GUI client, supplied with an in-process server (see servers) for testing. | |
| Various clients | ClntDemo2.zip usefully displays all OPC interface calls in a logging window. Also available are demo clients for Alarms & Events and Historical Data Access. |