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A vendor-unifying communication standard

10 May 2016

Suzanne Gill spoke to automation vendors involved in the development of OPC-UA solutions to gather their thoughts on the technology and where it fits into their industry offerings.

OPC has a 20-year history in the market of industrial communication and is a well-established platform for industrial communication between SCADA systems and fi eld applications. However, it has always been limited by its dependence on Microsoft’s DCOM technology which led to the development of OPC-UA (Unified Architecture). Being TCP/IP based, it is independent of any operating system so can provide an open communication solution right down to the device or controller.

Momentum is now starting to build very quickly around OPC-UA, and there is more talk about detailed OPC-UA implementation. The need for secure horizontal and vertical integration in the industrial environment is a relatively new requirement that is being driven by the IIoT and industry initiatives such as Industry 4.0 and there appears to be general agreement that OPC-UA offers the solution to future industrial communication requirements. The majority of industrial user organisations and communication foundations are now talking to, and working with, the OPC Foundation to provide OPC-UA solutions or gateways.

Native cyber security
Cyber security is a big concern in industry today and the fact that OPCUA is natively cyber secure is expected to be another contributing factor in its rapid and accelerated ongoing deployment. Today OPC-UA is the only communication standard that directly implements security models with encryption.

Schneider Electric sees OPC-UA as a key strategic technology that will enable and accelerate the adoption of IIoT in smart manufacturing. “It is an open but cyber secure industry standard technology that provides a platform and vendor independent interface between devices and controllers at the fi eld/ process (OT) levels, as well as increasingly bridging the OT-IT gap that still exists today between control and enterprise layers,” said Dave Sutton, product marketing manager at Schneider Electric.

“IIoT requires the exchange of device data, as well as standardised semantics and mechanisms to allow smart connected products, machines and assets to interoperate and discover each other in a transparent way. OPC-UA aligns perfectly with comprehensive description language, enabling the exchange of information models of any complexity and our customers will benefit from reduced engineering and integration,” he continued.

OPC-UA is a strategic technology for Schneider Electric that is on many of its product roadmaps for implementation – including inclusion in software servers, and embedded at device level.

“Where there is a need for a robust mechanism to serve plant data up to SCADA servers, there is a need to remove traditional PC based technologies. As OPC-UA is both platform independent and cyber-secure it addresses this need head on, enabling a reduction in overall points of failure, increased resilience and security. This is why embedded OPC-UA will be implemented in a much broader range of products, including PLCs, or the new generation ePAC automation controllers,” said Sutton.

“OPC-UA is more complex to implement than OPC Classic, and this may be reflected in early product development costs, but economies of scale will drive migration to OPC-UA,” continued Sutton. Industrial automaton vendors therefore also have a key role to play in accelerating the acceptance and adoption of OPC-UA.

Standardising redundancy
OPC-UA has many features that are important for process industry specialist Yokogawa. Frank Hurink, manager Global SCADA Centre for Yokogawa Electric Corporation, said: “Embedded redundancy, for example, helps our products improve the availability of OPC-UA communication channels. Many communication standards do not include redundancy out-of-the-box so the vendor builds their own interpretation of redundancy. The OPC-UA standard has this feature embedded so many vendors will now have the same implementation. While Yokogawa is striving for the best availability for our products, this improved availability for communication is crucial.”

OPC-UA is also very suitable for use in large-scale operations. “Where OPC Classic communication had limitations, OPC-UA is both Internet and firewall friendly which allows its use across large geographically spread environments. Various company processes can be connected and supervised from a central location. Our customers will benefit from this through the ability to analyse on a real-time basis information from various locations and to compare this,” continued Hurink.

Connecting industrial devices, systems, and applications to provide plant and enterprise personnel with actionable information is not a new concept. Indeed, many automation and software suppliers have been working to address this requirement, often not entirely successfully, due in large part to poor interoperability between OT and IT which has, traditionally, hampered business performance. “Yokogawa is supporting and participating at OPCUA interoperability events to ensure enhanced communication between vendors which will help to lower integration costs for our customers,” concludes Hurink.

Semantic interoperability
OPC-UA is a standard that we regard as being particularly relevant,” said Heinz Eisenbeiss, head of marketing Factory Automation at Siemens Division Digital Factory. “With its means for semantic interoperability OPC-UA is a key element to enable increasing data exchange between components in both factory and process automation. We see OPC-UA as a perfect complement to PROFINET to meet all the demands of communication tasks from the fi eld level to the management level. As an Ethernet based protocol, OPCUA is easily implemented on existing PROFINET infrastructure without any additional interfaces or gateways. By using the same infrastructure/cable without any limitations in functionality or bandwidth, this combination of well-established protocols provides benefits in both factory and process automation.”

Siemens utilises OPC standards in its industrial network products, HMIs and motor management systems and is currently supporting a working group whose aim is to define a new companion specification for RFID and other identification systems. “The next step for Siemens is the integration of OPC-UA into our controllers to allow us to offer a consistent portfolio on all levels of automation,” said Eisenbeiss.

Festo also utilises OPC-UA in a wide variety of products including its remote I/O platform controller, the CPX-CEC Codesys controller and its valve terminal ranges combined with remote I/O and controllers as well as the compact Codesys controller and the CDPX HMI.

Festo has also provided mechatronic subsystems as complete customer solutions incorporating OPC-UA. Current examples include a modular handling platform based on a CECC controller; a servo press based on a CECC controller; a multi-carrier-system which includes OPCUA as optional feature (created using a Siemens S7-1500 controller); and the delta-kinematics, a tripod robot without a cabinet, which employs a CPX-CEC controller.

Festo Didactic is also using OPC-UA as part of its CP-Factory, a training centre for Industry 4.0 solutions. SAP and Festo Didactic are also running test installations to demonstrate direct OPC-UA connections between their systems.

“Because standardisation is at such a low level today, we believe that OPC-UA offers a strong contribution to factory automation,” said Eberhard Klotz, head of marketing products and technologies at Festo.” Time sensitive applications (for example motion control) between machines are not the current focus of OPC-UA but it is hoped that the TSN standards expansion might bridge this gap in the future. We believe that more detailed OPC-UA communication profiles and definitions are needed – in the same way that was achieved by the SmartFactory communication between machine modules from several suppliers. Harmonised definitions on how to tunnel OPC-UA through existing Industrial Ethernet protocols would also be useful for OEMs and end users,” said Klotz. “OPC-UA is the only reliable standard that we have and, in the same way that Industry 4.0 is based on evolution not revolution, we do expect to see OPC-UA grow and develop.”

Connection to the IT world
Softing has recently integrated an OPC UA Client interface to its dataFEED OPC Suite, to simplify migration to Industry 4.0 solutions by allowing controllers with integrated OPC-UA Servers to be easily and cost-effectively integrated into existing OPC Classic environments. “OPC-UA is a good management platform for industrial data, and offers standard connection into the IT world,” said Hans-Werner Auberg, managing director at Softing Industrial Automation. “It is the only open standard that provides access for everybody.

OPC-UA, consists of a client-server architecture. One part of the server provides the data and another acquires data, always in a fixed point-to-point relation. This is done asynchronously, so while one is doing the acquisition and the cyclic process, the other one is taking the data out of the system at some time-point,” said Auberg. “OPC-UA benefits from utilising a Publisher/Subscriber communication model which gives the functionality to define a fixed time-window when you exchange data, not point-to-point but with a multi-point connection via UDP. This gives a communication frame that is addressed to many other controllers, not only to one, so you have a defined timeframe with multiple addressing.”

Sensor to cloud
Hilscher is using OPC/UA in its netIOT product line, which offers a complete data fl ow from the sensor up to the cloud. “OPC/UA is implemented in our field device communication stacks, running IoT communication parallel to Industrial Realtime-Ethernet, said Stefan Körte, director of sales and marketing at Hilscher. “OPC/UA provides the ideal base for this, because it is accepted and supported by most field device manufacturers.

“We see OPC/UA as a very important protocol for IoT-communication. It offers the possibility of vertical communication from fi eld devices on the factory floor right up to the ERP system within an IT infrastructure. The specification of OPC-UA is wide and flexible enough to be used as a common protocol within complete cloud based infrastructures. We also see OPC/UA developing to become a standard for Cloud communication. It has the right structure to cover the actual and future demands in IoT communication and is certainly the right choice to start IoT applications in the automation field.”

Unlocking Industry 4.0 potential
When Opto 22 looked to enhance the interoperability of the groov mobile HMI it was able to leverage the OPC-UA standard to quickly add rich communication capabilities. According to Matt Newton, director of marketing for Opto 22, OPC-UA provides one of the keys to unlocking the potential of Industry 4.0. “Its greatest benefit is that it is a communication protocol that can be used on any device and any operating system, including embedded systems that may not run the Windows operating system.”

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