Page 30 - EngineerIT April 2022

AUTOMATION

and in a comprehensive manner. OPC UA is a particularly impressive Ethernet-based
communication standard that, due to its independence from manufacturers, programming
languages and platforms, gives companies maximum flexibility in the design of their IoT
systems.
OPC UA is significantly different from deterministic fieldbus protocols such as PROFINET
or EtherNet/IP, which are familiar from the control world. While these protocols are usually
supported only by specialised controllers from the respective manufacturers, OPC UA is
ideal for manufacturer-independent communication with a wide range of computer-based
or cloud-based systems. Corresponding OPC UA clients, which create the interface to the
OPC UA server, are available for various operating systems and directly integrated with the
major cloud providers. Due to the independence of OPC UA, customers are free to develop
their own interfaces. Corresponding supporting development kits are available in this
regard from the OPC Foundation. Another difference is the performance alignment of the
protocols. While the control-based communication protocols are primarily geared toward
real-time applications with cycle times in the millisecond range, OPC UA is used as more of a Lukas Pogoda
parallel, non-time-critical information data channel into the cloud and places less stringent
demands on real-time. be processed in a local evaluation tool
using external software, or uploaded to
Division of tasks between PLC and cloud the cloud without interpretation. Users
Pepperl+Fuchs is the first manufacturer to combine the advantages of IO-Link and OPC UA can decide if the cloud is located on the
in a single device. By combining a deterministic fieldbus protocol – such as EtherNet/IP corporate network or the internet; they
or PROFINET – and OPC UA in a single device, the new IO-Link masters of the ICE2 or ICE3 also define the security levels. For this
series can communicate in parallel with a controller and a higher-level PC-based system purpose, the IO-Link masters support
or cloud. Hybrid systems are thus possible, in which the PLC controls the application in both authentication mechanisms and
real-time via PROFINET or EtherNet/IP, and the IO-Link master simultaneously transfers certificate management.
status data to the cloud via OPC UA, which is of no relevance for the controller but crucial
for another machine or a central control system. Since controllers are specially designed Control from the cloud
for processing sensor input signals as quickly as possible, and transferring the output The modules from the ICE2 and ICE3
signals resulting from the control logic back to the actuators as quickly as possible, they series allow data not only to be read out
are not suitable for large amounts of status data. They can be processed much more from the IO-Link devices via OPC UA, but
cost effectively than in computer-based or cloud-based systems, which means expensive also enable write access if required. For
computing resources are not required in the controller. By adopting this approach, data can each of the eight ports, it is possible to
specify separately for each one whether
data should only be read or written via
OPC UA. In principle, applications that do
not require control in milliseconds can
be implemented in their entirety without
a traditional controller. As computer-
based and cloud-based systems increase
in power and capacity at the same time,
control tasks can be assumed at a small
cost.

Ready for the digital future
With the new IO-Link masters with
integrated OPC UA interface, customers
are already able to prepare for the
digitalisation of their plants. The OPC UA
functionality can be enabled and disabled
with complete flexibility at any time. This
means that customers can already equip
their plants accordingly, without a specific
application for OPC UA, and unlock the full
potential of the ICE2/ICE3 IO-Link masters
OPC UA paves the way for the digital factory at any time in the future. n

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