Is the concept of open standards all myth and magic? Is there a real business and technical value proposition for open standards like OPC that justifies the end users demanding the suppliers to deliver? How does OPC provide timeless durability and deliver specifications and technology that the suppliers build into their product portfolios? This article explores the OPC vision, and the who, what, when, where, and why of OPC interoperability.
OPC became the de facto standard for data acquisition for discrete and process control applications, and over time has evolved and revolutionized industrial automation multiplatform interoperability. The OPC Foundation strategy is providing the infrastructure to enable the community of suppliers, consortia, and end users to collaborate to bring interoperable products to market. In addition, the OPC Foundation had established a certification program that validates the interoperability of products to meet and exceed the quality standards of the end user community.
What are the benefits?
Typically suppliers have always preferred the brand-loyalty architecture; we want our end users to only use products from “our” company and our preferred suppliers. The suppliers assert and assume they know what their end users want and need! Suppliers always tell the story that standards are the least common denominator approach, and they can give users better compatibility and performance along with guaranteed interoperability with their proprietary architectures.
The world of consumer electronics and the expectations set with out-of-the-box multivendor plug-and-play interoperability is changing the world. End users have high expectations that technology innovations in consumer electronics must be propagated to industrial automation, and that tablets and smartphones must be integrated with their industrial automation devices and applications.
Has the OPC Foundation successfully delivered the right technology and value proposition to change the landscape of industrial automation and related domains?
OPC was started in 1995 by a group of companies that had the vision for a simple interface that allowed first-tier visualization applications on Microsoft platforms to read and write data from process control and factory automation devices. The value proposition at that time was simple; vendors were looking to make their lives simpler and more cost-effective. They did not want to be burdened with continual development of complex device-driver software to talk to the myriad devices. Before OPC, companies had developed their own “proprietary open” technology and distributed tool kits to multitudes of vendors to develop software as an interface for their software to discrete and process devices.
When OPC first started, it was all about a small set of vendors. It was a community thinking and collaborating to solve a critical problem of moving data from the factory and process control devices to the first-tier visualization applications. The key concept here is a community collaborating together.
OPC continued to develop new standards beyond the first data-access specification that was developed in the mid-1990s. OPC solves problems beyond data access, including specifications for alarming and historical data access. The Microsoft platform-based specifications of data access, alarms of events, and historical data access are now labeled the classic OPC specifications.
OPC Unified Architecture
Requirements and technology continued to advance, which established the need for a new architecture that addressed a far broader scope of interoperability problems.
In 2004, the OPC Foundation took on the task of developing this new architecture called the OPC Unified Architecture (OPC UA), which provides a service-oriented architecture designed to provide multivendor, multiplatform, secure, and reliable interoperability. The OPC Unified Architecture unifies all the data and information models from the classic OPC specifications. It provides an extensible information model that allows not only OPC classic data to be modeled, but also allows other consortia and vendors to render their respective information models into an OPC UA “name space.” This unique information model architecture allows applications to exchange data/information with applications and devices, without having advance knowledge of the “data structures.”
The OPC Foundation membership is the community that continues to collaborate to develop the best specifications, technologies, certifications, and processes. Years ago, the focus was exchanging data inside a corporate firewall. No one “really” worried or thought too much about security. No one thought about the volumes of data and what to do with the volumes of data. Yesterday and today, it is all about converting terabytes of data into intelligent information. After OPC released OPC Data Access, the OPC Foundation continued to work with the community of collaborating vendors to look for other interoperable problems. Some of the specifications that resulted solve the problems of alarming and historical data access.
Classic OPC is the “base” of the OPC Unified Architecture. OPC UA expands classic OPC from the embedded world to the enterprise. It is all about connectivity in and between industrial automation and all the related domains.
One of the first OPC Foundation collaborations was OpenO&M (operations and maintenance), which was a partnership between organizations including MIMOSA, ISA95, OAGIS, and OPC. It was based on the initial work between OPC and MIMOSA, focusing on asset management and the idea of preventative maintenance and reliability applications. MIMOSA really provided the deep repository of information, and OPC became the mechanism for transporting the information between various applications.
In the past two years, the focus has been elevating the collaboration with other consortia and capitalizing on the information modeling concepts inside of the OPC unified architecture. The focus of the collaborations has spanned oil and gas, building automation, smart energy, and machine-to-machine connectivity. Some of the specific consortia that the OPC Foundation is collaborating with include MDIS, DSATS, MTConnect, PLCOpen, BACNet interest group Europe, Energistics SLC, ISA95, and ODVA/Sercos.
So how does this collaboration architecture work? First, OPC has what is known as the information model architecture. The OPC classic specifications, including data access, alarms and conditions, and historical data access, are modeled as information inside the OPC name space. OPC UA took the classic OPC specifications and separated out the services from the information. This enabled us to identify the key services of reading, writing, browsing, subscription, and security and to keep them generic from the information that they operate on. We are also able to provide complete structures of information behind the data, which can be thought of as the data and then the metadata behind the data.
OPC provided its own information model for its various classic OPC specifications. Then the OPC Foundation looked at the opportunity to model information from other vendors and other consortia’s information in a generic way.
The best way to explain the information model is to show a picture and show the separation between the OPC UA-based services and the OPC information model and the specifications of the information model from other collaborative organizations.
In the oil and gas community, OPC is engaged in a collaboration called MDIS, which stands for master control system (MCS) – distributed control system (DCS) interface standardization (IS). All the major oil companies (the operators), all the major DCS vendors, and all the subsea vendors collaborated to standardize the objects for automation from the subsea world to the DCS. They wanted to standardize on their communication protocol and information model, with the benefits being reduction in cost and simplifying engineering. The key features that they will use from OPC UA are subscription, security, robust medication, and redundancy-but most importantly leveraging the information-modeling capabilities, including all of the subtyping of information. The architecture possibilities include connectivity to the subsea vendor hardware through a subsea gateway that is topside to the MCS and ultimately to the DCS human-machine interface (HMI) system. Standardizing information will allow all the equipment to operate seamlessly and talk the same semantics and syntax. Multivendor interoperability at its finest leverages the capabilities of the information model and OPC UA. And an OPC UA companion specification is being developed that will describe all the objects inside the system and all the information necessary to provide the infrastructure for interoperability and compliance.
In other areas of oil and gas this is known as drilling system automation (DSA-TS). This is all about looking at the surface equipment of a drilling rig. How do you model all the objects and integrate information between multiple vendor systems? This is collaboration between all the operators, the drilling contractors, the equipment suppliers, and the service companies that essentially are cooperative adversaries interested in information modeling and interoperability. The companies that work together will ultimately reap the benefits of OPC UA. There will be commercial off-the-shelf products that will easily support the complex information models, providing high degrees of maintainability in a secure fashion. One of the key standards is known as the well (oil and gas well) information transfer standard, which will be in the OPC UA information model and is used throughout the drilling industry.
Finally, in the oil and gas world is the Standard Leadership Council. The OPC Foundation is proud to be engaged in this important initiative where all the upstream oil and gas consortia are cooperating. One of the specific initiatives coming from this particular effort is the integration between OPC and Energistics. We are putting together a working group that will develop an OPC UA companion specification for PRODML.
Outside of oil and gas we have been working with the building automation community. Specifically, the OPC Foundation is engaged with the BACnet interest group Europe, which is promoting BACnet in the European markets. BACnet is a data communication protocol for building automation under the auspices of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers. It is considered the global standard for communication in building automation systems. In the fall of 2012, the OPC Foundation and the BACnet interest group formed a working group with the main task of creating an information-mapping model for OPC UA and BACnet. Excellent work is being accomplished where we are taking data from building automation inclusive of energy-metering data, real-time operating information, and maintenance information to simplify the integration with enterprise systems, including accounting, operational surveillance, and extensive energy-monitoring applications. In addition, we are able to take data from automation systems inclusive of the production information programmable logic controller (PLC) and DCS used in building automation and other energy supply systems and integrate them with historical data storage and scheduling applications.
OPC UA was initially focused on providing the infrastructure necessary for data and information integration between the control systems in the information technology world. As OPC began to provide the necessary services with respect to security and the corresponding scaling of services for platform independence, we recognize a unique opportunity for OPC UA to actually be scaled down into the embedded world. OPC UA has now been ported and made available on the smallest level chips, and at the same time OPC UA is now available in a variety of PLC and DCS systems, and numerous vendors are building OPC UA into embedded HMI devices. More importantly people are starting to look at OPC UA as a mechanism for data integration down into the instrument level. OPC UA can exist anywhere. This existence anywhere will allow the integration between industrial automation and multiple related domains.
With respect to the embedded world and collaboration, we have an excellent collaboration between OPC and PLCOpen. In 2009, the initial plan was put together to map data structures inside of IEC 61131 into an OPC UA name space, and the initial goal was completed by March 2010. In 2000, we began the development of PLCOpen OPC UA function blocks and services. The OPC client now resides inside of the PLC and is able to interact through programmatic method calls into the manufacturing execution system world, which behaves as an OPC UA server running in the cloud. The applications of this are very interesting, and we now have the ability to make transactional calls from a PLC leveraging the collaboration between OPC and PLCOpen.
The collaboration examples between the OPC Foundation and other organizations are just the beginning in the journey to standardize information integration.
The value proposition of open standards recognized in the world of consumer electronics is gaining momentum in industrial automation. Expectations are clear from the engineers of tomorrow-they rely on multivendor plug-and-play interoperability in consumer electronics and expect multivendor plug-and-play interoperability from industrial automation. More importantly, the ability for all the standards organizations to work together in a harmonization of those information model standards is being realized through the organizational collaboration taking place across our industry.
The multitude of members inside the OPC community are bringing forward products and services that take advantage of the multiplatform architecture from the world of consumer electronics and entertainment. The smartphone has become a way of life. People use their smartphones as a replacement for global positioning systems. People use their smartphones for bidirectional information exchange. Smartphones have become many people’s computers. The proliferation of applications and the importance of applications being developed that tie into the world of industrial automation can now be realized in a standard way by leveraging the OPC UA technology.
In summary, the business value proposition for open standards and specifically OPC is really all about looking at the total cost of ownership, and how products from multiple vendors can have frictionless information integration out of the box with plug-and-play interoperability. Consumer electronics are driving expectations for industrial automation end users and engineers of tomorrow. Frictionless interoperability can now be realized by all our suppliers developing best-of-breed products that leverage open standards inclusive of the OPC technology portfolio.