The OPC Foundation has been working to help solve communication and connectivity problems between plant and factory floor devices and host systems and applications since 1995. Virtually every end user, OEM and automation supplier employs OPC standards, such as OPC Data Access (OPC DA), OPC Alarms and Events, (OPC A&E), and OPC Historical Data Access (OPC HDA), to establish communications and connectivity between disparate devices.
However, no longer is connecting devices at the field, control, and operations levels sufficient; today’s users also need to connect plant devices, applications and systems up to the enterprise level. Many OPC users have also expressed concerns about the security features of OPC communications, which previously were limited with the early versions of OPC classic communications.
The OPC Foundation recognised the opportunity to enhance interoperability and provide platform interoperability by developing new specifications through participation by a new category of enterprise and embedded suppliers in OPC Foundation activities. The new specification – OPC Unified Architecture (OPC UA) – has been demonstrated to improve secure interoperability between all plant equipment and systems and between the plant and enterprise, helping eliminate islands of information.
The questions are: Is OPC UA real? Have suppliers begun to incorporate it within their solutions? And, if so, how are users taking advantage of these solutions? This article, based on the session, ‘Transforming manufacturing with OPC UA: From embedded to the enterprise’, at the recent ARC World Industry Forum in Florida, addresses these questions.
Embedded OPC UA
The OPC UA specifications, initially released in 2006, integrate functionality from the existing OPC specifications (OPC DA, OPC A&E, OPC HDA) into a comprehensive service-oriented architecture. OPC UA adds essential new properties, including platform independence, scalability, high availability, new security mechanisms, and web services. OPC UA has two dimensions:
1. To provide secure interoperability at the automation level by embedding the technology within plant-level devices and applications.
2. To extend OPC communications from the device and automation levels up to enterprise applications and systems.
Embedded OPC UA is based on an attractive lightweight architecture, with the minimal embedded OPC UA implementation using an efficient binary communication protocol. As a result, embedded OPC UA can be ported to many embedded operating systems, including proprietary real-time operating systems.
Embedding OPC UA on a chip
Liam Power, technical director at Embedded Labs, a software company based in Waterford, Ireland, presented ‘OPC UA on a chip, redefining automation architecture.’ Liam cited examples of OPC UA applications embedded on a chip being used to provide connectivity for scheduling, control, visualisation, logging, reporting and productivity applications.
Liam described how OPC UA embedded in low-cost microchips will enable seamless communication from the field device level all the way up to MES applications. He stated that OPC UA will soon be embedded throughout the automation system in everything from serial fieldbus to OPC gateways, PLCs/PACs, I/O blocks, motor drives and sensors and actuators. Liam also predicts that, by the year 2020, less than one in 1000 OPC UA servers sold will be as installable software for PCs and that the installed base of embedded OPC UA devices will exceed 50 million units.
Embedded OPC UA integrated into PLCs
In his presentation, Christian Schulze, business development manager for Beckhoff Automation, discussed how his company has incorporated embedded OPC UA into the architecture of its products. According to Schulze, OPC UA has been embedded into its Automation Controller series, which includes PLC, motion control and graphical user interface functionality. The embedded OPC UA server is integrated with DA (data access), HDA (historical data access), and A&E (alarm and events). The embedded OPC UA client is already integrated with IEC61131-3 programming software function blocks. Embedded controllers acting as an OPC UA client can initiate communications to other OPC UA server-enabled field devices and, in the near future, to HMI/MES software acting as an OPC UA server.
Embedded OPC UA found at all automation levels
Mitch Vaughn, chief technologist, HMI Center of Competence, Siemens, presented how the company integrates its solutions using embedded OPC UA. According to Vaughn, Siemens introduced its first OPC UA-based product in 2008. Today, one of its products has been certified as OPC UA-compliant, with ten more products in the immediate pipeline. He explained how Siemens plans to use embedded OPC UA solutions at all automation levels. Future products will include numeric and motion control, drive management and diagnostics, industrial network management and analytical devices.
The benefits of OPC UA include standard interfaces across all automation levels, operating system independency and a higher degree of security compared to ‘classic’ OPC. OPC certification for OPC UA products will also help ensure better interoperability and higher customer satisfaction through improved robustness.
Embedded OPC UA enables operational excellence
In his presentation, John Krajewski, senior product manager HMI/Supervisory for Invensys Operations Management, discussed how embedded OPC UA will serve as a key enabler and one of the primary real-time system connectivity tools within the company’s InFusion enterprise control system, including the ArchestrA System Platform, ArchestrA Workflow, Trident safety instrumented systems, and SimSci-Esscor ROMeo plant optimisation software. According to Krajewski, these encourage control excellence, people excellence, safety excellence and asset excellence, respectively.
OPC UA plays key role in ODVA’s collaboration with OPC Foundation
Katherine Voss, executive director of ODVA, presented a vision shared with the OPC Foundation for machinery integration in the manufacturing sector. ODVA, a vendor member organisation founded in 1995, has approximately 275 global vendor members. As a standards development organisation and certification body, it manages and promotes EtherNet/IP, DeviceNet and other ODVA technologies. In March 2011, ODVA announced a machinery initiative in partnership with OPC Foundation and Sercos International to foster cross-collaboration on topics of mutual interest for machinery applications.
Embedded OPC UA deployed in drilling automation
Clinton Chapman, drilling automation programme architect for Schlumberger, presented how the company uses embedded OPC UA in a drilling automation application. Chapman explained that since so many different organisations (owner-operator, equipment suppliers, service companies, etc.) are involved in drilling automation, it makes it difficult to provide integration points. This is due primarily to security and differences in equipment.
This Society of Petroleum Engineers Drilling System Automation Technical Section (DSA-TS) was formed to ‘accelerate the uptake of drilling systems automation by supporting initiatives that communicate the technology, standardise its nomenclature, promote lessons learned/best practices, and help define its value proposition.’
Chapman said that the first phase of this project was to decide on a protocol and tags for control. DSA-TS selected embedded OPC UA as the protocol and to generate a set of tags that could be used to control the systems. OPC UA was chosen because of general agreement that OPC has broad industry support, because OPC UA components are available off-the-shelf with drivers and (freed from the limitations of COM/DCOM) OPC UA offers an attractive security model. This was particularly important because service companies and other third parties are typically involved during the drilling process. Also, both compatibility with multiple HMI/Scada systems and the availability of OPC DA-to-OPC UA converters strongly influenced the decision to move forward.
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