Perfect complement for an Industry 4.0 implementation
Implementation of Industry 4.0 requires digital consistency in production - from sensors all the way up to the ERP level. An increasing number of machine and system manufacturers are using a combination of OPC UA and POWERLINK to integrate devices from different manufacturers and various levels of the automation pyramid into a complete system.
The complexity of industrial automation tasks is continually increasing, leading to the development of more and more distributed control concepts. These approaches allow for individual, flexible and modularly structured automation technology as intelligent peripheral devices connected via industrial Ethernet become increasingly prevalent. It is becoming more common, for example, for individual parts of machines or machine components to be equipped with their own controllers and grouped together to make up a complete machine.
"Effective communication between individual subsystems and components is of crucial importance for the productivity of these types of solutions," explains Stefan Schönegger, managing director of the Ethernet POWERLINK Standardisation Group (EPSG). "For machine and system manufacturers, it's very important that their ability to implement a process in a machine or system is not limited by proprietary solutions." From the control to the enterprise level, OPC UA is an ideal communication protocol.
OPC UA is an open standard that is now implemented by all the major control system manufacturers. This standard ensures that machines with controllers from different manufacturers can be easily coordinated within a system. The protocol itself is also platform-independent, and the communication stack can be ported to any operating system or embedded hardware. "OPC UA is the only protocol that combines all of these benefits," says Schönegger. "That's why there is increasing market demand for OPC UA to be strengthened."
In relation to IT applications, OPC UA is ideal for line communication, but there are other requirements that are relevant for communication between controllers, I/O channels and drives. "It can be disastrous if data doesn't arrive on time," explains Schönegger. "Even small deviations in the microsecond range can result in damage to mechanical equipment." Protocols used for this purpose must be reliable in hard real-time applications with cycle times of less than 1ms. "POWERLINK is the ideal complement to OPC UA," says Schönegger.
Like OPC UA, POWERLINK is purely a software-based protocol with a stack that can be accessed externally and ported to all other platforms. "The combination of OPC UA and POWERLINK provides the maximum amount of freedom when engineering machines and systems," says Schönegger. Using PLCopen-compliant OPC UA function blocks makes it easy to engineer applications - regardless of the control system manufacturer.
B&R will be supporting the OPC Foundation's new working groups, whose goal is to add real-time capability to the OPC UA communication standard. This will involve two key additions to the OPC UA standard. The first is a publisher-subscriber model; the other is utilization of the IEEE 802.1 standard for time-sensitive networking (TSN).
B&R will be contributing its real-time expertise to the working groups. "The updates to the OPC UA standard will benefit from our years of experience in developing real-time solutions," says Schönegger.
OPC UA already features a familiar client-server architecture. The publisher-subscriber model will add one-to-many and many-to-many communication that will have decisive benefits for communication speed in large distributed systems. "This is a fundamental requirement for the M2M communication you find in integrated systems such as packaging lines," explains Schönegger. POWERLINK is also based on this same architecture.
In order to fulfill real-time requirements, the OPC UA standard will make use of the IEEE 802.1 TSN standard. "At the moment, TSN is still a working title for a group of new IEEE standards designed to provide native real-time capability for the IEEE 802 Ethernet standard," says Schönegger. This would allow for a seamless transition to substantially faster Ethernet standards such as POWERLINK for field-level communication and demanding motion control tasks.
Beyond the automation industry, TSN is currently also being evaluated by the automotive and telecommunications industries. "The first cars based on TSN are expected to hit the market in the very near future," reports Schönegger. This would help secure the widespread availability of this technology. In addition to B&R, the new OPC working groups will be also supported by other leaders in the field of automation, as was announced by KUKA on April 13, 2015.
OPC UA already plays a central role in the IT-related areas of modern production systems. "The addition of TSN and the publisher-subscriber model will greatly expand the range of potential OPC UA applications," says Schönegger. Paired with the open standards POWERLINK and openSAFETY, the result is a total package for safe and consistent Ethernet communication all the way down to the sensor level.
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