14
industrial ethernet book 2.2017
Technology
THE OPC CLASSIC STANDARD has been used, in
the past, to effectively enable access to device
data for external applications. However, as
this standard no longer covers advanced
requirements, companies such as Lenze are
now opting for the development of an OPC
UA server.
Lenze is one of the global specialists for
drive and automation solutions in mechanical
engineering. Its comprehensive portfolio of
drive solutions, complete automation systems,
engineering tools, modular software, and
one-stop services forms the basis, making the
implementation, production, and application
of technical equipment as easy as possible for
the customer. This is greatly aided by the use
of open standards and interfaces.
The EASY Starter development tool from
Lenze combines the functionalities for quick
and easy device commissioning and for device
maintenance by service technicians.
A GUI with a restricted number of
buttons enables easy parameterization,
commissioning, and online diagnosis of all
Lenze devices, including control systems. What
is more, EASY Starter allows loading of entire
applications onto a device. The EASY Starter
enables integration of various communication
links via Ethernet, eldbus systems, and the
USB interface. This tool further comprises the
logic used for the detection of Lenze devices
and for the selection of an appropriate device
description as well as specic methods for
accessing device features.
Migrating to OPC UA
In line with the basic Lenze principle, users
access the Lenze device parameters using
third-party software. For this purpose, a
standardized, secure, and future-oriented
interface is used which is not bound to
particular eldbuses and platforms. In the
past, this was the job of the Lenze drive server
operating on the basis of the OPC Classic
standard.
This server, which uses Microsoft’s COM
technology, encapsulates the communication
protocols used and provides the device
parameters to other automation applications
such as visualization systems. However, the
COM technology is aging and its maintenance
is a tedious task. In addition, this standard
no longer covers modern requirements, such
as the implementation of security features.
In their quest for a future-proof solution
approach that replaces OPC Classic, Lenze
investigated the OPC UA (Unied Architecture)
standard. Besides the supported functionality,
the evaluation focused on performance
aspects, as it was important that especially
the time-critical requirements could be
Gearing up for rapid application
development using OPC UA
Instead of developing an OPC UA Server as an all-proprietary solution, new development toolkit technology
provides generic data exchange using encapsulated libraries which can be integrated into the application
through a standard programming interface, reducing complexity and dramatically reducing time-to-market.
SOURCE: SOFTING/LENZE
OPC UA Server integrates with the “EASY Starter” tool.
OPC UA supports a consistent data exchange between the eld and enterprise levels.
SOURCE: SOFTING/LENZE
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2.2017 industrial ethernet book
covered. But also the comprehensive security
concept, the Internet-based communication,
the potential use on embedded platforms, and
the fact that the Industrie 4.0 requirements are
covered spoke in favor of the OPC UA standard.
After careful consideration, Lenze opted for
the development of an OPC UA Server.
Choosing the appropriate toolkit
As an alternative to developing the OPC UA
Server as an all-proprietary solution, an OPC
development toolkit lends itself to this task.
The toolkit provides the generic data exchange
functionality in the form of encapsulated
libraries which can be integrated into the
application through a programming interface.
Using this approach, it is possible to
save one man-year of software development
effort or more which, in turn, allows for a
dramatically reduced time-to-market. To
benet from these advantages, Lenze opted
for the UPC UA .NET development toolkit from
Softing Industrial Automation.
Two more criteria contributed to the
decision. Softing’s toolkit supports the .NET
environment as used by Lenze in their EASY
Starter tool, which simplies the development
process. Softing also offered a workshop aimed
at giving the Lenze employees extensive
training on how to use the OPC UA development
toolkit for their server development.
Softing’s OPC UA .NET Development Toolkit
provided Lenze with a comfortable and
properly documented programming interface
for the application. The libraries it contains
are state-of-the-art with respect to the OPC
specifications and fully conform with the
standards to provide optimum interoperability
with other OPC UA components. The OPC UA
proles supported by the toolkit include UA
Extended Security, Data Access, Complex Data,
Eventing, and UA Historical Access. Currently,
Lenze only uses Data Access.
This prole also provides for the realization
of integrated security systems that enable
secure data transmission to remote locations
and reliable protection from modern threats.
The toolkit comes with complex test and
simulation clients and servers for fast
development.
Access devices using OPC UA
When developing the OPC UA Server, Lenze
relied on the sample applications and tutorials
delivered with the toolkit, in combination
with the hands-on practice gained from the
Softing training course. This way, the EASY
Starter interfaces could be linked quickly with
the toolkit interfaces.
When the integration into the EASY Starter is
complete, the users benet from functionality
for using the device information in other
applications. The rst step is to congure
the OPC UA Server within the existing, basic
user interface. For this purpose, an online
connection is established to all devices which
should be accessible through the OPC UA
Server.
This involves selecting the communication
paths used and searching for the connected
devices or addressing them manually. After
saving the conguration and launching the
OPC UA Server, a connection to the congured
devices is established, identifying each
station, and assigning the associated device
description.
The result is that the object directory or the
parameter list of a connected device is known
and available to other devices throughout the
system. The congured system is available in a
tree structure on the OPC UA Server, enabling
access to each parameter from an OPC UA
Client via a unique path.
Convincing application results
The implementation of the OPC UA Server
and the release for series production could
be accommodated within the usual bi-annual
release planning. An additional benet for
Lenze in this process was Softing’s short
response times for questions. During the
implementation, the OPC UA test clients
that came with the toolkit were available for
functionality and performance testing.
Today, Lenze operates the OPC UA Server
as a future-proof interface for the access to
the Lenze devices for parameterization tasks.
The fact that it supports the OPC UA standard
allows the platform-independent and secure
use of remote maintenance and visualization
applications. Several customers relate this
option to Lenze’s innovative potential and
future-orientation, leading to a positive
perception of the company. This spawned
several inquiries that already resulted in new
customer contacts.
Off-the-shelf or proprietary?
For many standard platforms, turnkey OPC
servers available on the market are intended for
large-scale use and usually only cover common
requirements. With the use of an OPC toolkit,
on the other hand, fast implementation of
customized OPC solutions is possible without
being compelled to delve too deep into the
OPC technology.
This way, specific requirements can be
met and individual communication protocols
can be integrated. Other advantages of this
function library are related to its versatile
application. They include benets such as
increased quality and robustness as well as
improved efciency and performance resulting
from ongoing product maintenance. The
certication by OPC Foundation test labs and
the participation in annual interoperability
tests with other products also add to these
advantages.
Technology report by Softing.
