End users who purchase OPC-compliant products expect 24/7
reliability, full data information integrity and validated, secure
interoperability. The product should seamlessly integrate with existing
architecture. However, achieving interoperability of some products is more like
a running skirmish against hostile opposition -- painful and costly. Getting all
sides to comply with the rules and best practices of interoperability can be an
uphill battle at times. To combat the problem, the OPC Foundation has created
the OPC Enhanced Certification Program.
The clear message from users was they should not need to validate
interoperability between vendors. As an industry standard, OPC products should
work together seamlessly, securely and reliably. So, when the status quo isnât
sufficient and you foresee marauding forces gathering on the rise, what do you
do? Form a battle plan, strengthen the defenses, check the armaments and rally
the troops. Achieving the mission on true interoperability takes no less effort.
Paul Hunkar, Consultant Engineer with ABB, in his role as the OPC Foundation
Managing Director of Certification is the one tasked with leading the charge.
"The OPC Foundation is committed to
providing the support requested by our end-users and vendors to improve the
quality of OPC Products." says Hunkar. "The Compliance Committee, composed of end
users, vendors and system integrators, has spent significant time and resources
improving the processes available to vendors to improve the quality of their
The Battle Plan
A good commander will tell you any battle plan relies on good
reconnaissance, so existing OPC vendors and end users were surveyed to determine
what was working with the existing compliance procedures, and to identify
possible chinks in the armor. The key observations included:
current compliance efforts lacked visibility
it was not easy to identify OPC product
there was a demand for independent testing
facilities and improved testing tools
The OPC Foundation currently provides workshops and automated test
tools to help facilitate interoperability. Although these efforts are effective
to a certain degree, it was deemed additional improvements where needed to
ensure the delivery of quality certified products that exceeded the expectations
of the end-user community.
The OPC Product Certification section of the Foundation website has
been re-designed to make it easier to find OPC-certified applications. Each
product has a 'Certification Test Status' associated with each specification
that it supports. In addition, each product has an overall test status, which is
a composite of the individual specification test statuses. Using various product
search options, users can easily determine which OPC products have been fully or
partially tested, previously tested against older criteria, recently
workshopped, or have never been tested at all.
Another useful status is the âSimilar Product Testedâ category, which
is intended for OPC products that have been built on a common core framework.
Since a single framework may represent hundreds of different OPC servers, it
would be impractical for vendors to individually certify each OPC server with
each new testing tool release or workshop event.
In addition to improving the OPC Foundation website, the Compliance
Committee has replaced the existing âOPC Compliance Testedâ logo with two new,
revamped logos. The new branding will differentiate between OPC products that
have been self-tested by vendors using the OPC Foundation-supplied test tools,
and those that have been certified by independent third-party testing
facilities. This is another important step towards improving the visibility and
identification of certified OPC products.
The OPC Foundation has several applications in their testing arsenal.
Since OPC products are client-server based, and may support multiple OPC
specifications, different testing tools and approaches are needed. For OPC
Servers, the OPC Foundation provides a standard software application called the
Compliance Test Tool (CTT), which supports the various OPC specifications.
Members can download the CTT from the Foundation website and run the tests at
their site. The tool generates an encrypted file which is forwarded to OPC
Foundation, who then publishes the results on the OPC Product Certification
section of the website.
Testing OPC clients is more challenging, since many client
applications require only a subset of the full functionality provided by an OPC
server. There can also be tremendous variation in how an OPC client may be
incorporated into other software applications. The OPC Foundation meets this
challenge by offering interoperability testing. This is a process where members
attend an annual event and test the OPC client applications against the OPC
servers supplied by other members. These events are called interoperability
workshops and occur each year in Europe, North America and Japan.
The interoperability test process requires that OPC vendors run a series of
standard tests for each combination of an OPC client and an OPC server product.
The results of these tests are collected and displayed on the OPC Foundation
website as part of the overall Certification Test Status.
In spite of the variations of OPC clients available, there is a core
set of interfaces and functionality that users have come to expect from all
clients to improve interoperability. To ensure these tests are covered by the
interoperability workshops, the OPC Foundation has recently developed a
standardized OPC client test application called the OPC Analyzer. The tool not
only logs all interaction between the OPC client and server, it also has a
scripting capability that allows testers to generate error conditions or
unexpected behavior in order to test the robustness of the OPC clients. This
tool, along with network interrupt testing, allows vendors to determine how
their products behave in simulated real world scenarios.
The Big Guns
In addition to these activities the OPC Foundation is currently in
the process of ârolling out their big gunsâ in the form of independent testing
labs. This will further assist member companies with interoperability and will
provide end users with a known set of tested interoperability criteria for any
given OPC product. The aim of the test labs will be to provide testing beyond
basic interface compatibility. The tests would include features such as a fixed
reproducible testing environment, functional tests for both servers and clients,
behavior tests for normal and exceptional operating scenarios, performance tests
for long term and loading, unreliable operating environment and failure recovery
testing, as well as usability, installation and configuration testing. This is
an important major improvement in the overall OPC certification process that end
users will significantly benefit from in terms of truly seamless
Rallying the Troops
When Tom Burke, President and Executive Director of the OPC
Foundation was asked about the response from the OPC community to the rallying
cry for interoperability, he had this to say: âThe commitment from the vendors and end
users alike has been clearly demonstrated through the volunteer effort
developing the specifications and process to truly guarantee and improve
multi-vendor interoperability achieving the highest level of quality.â Tom
went on to say that â The message from
the end users and the reason for the OPC Foundation Enhanced Certification
Program is to provide a solid foundation for certifying products to meet and
exceed the end-user expectations with respect to the OPC Foundation technology
Lock and Load
The plan is firmly in place and deployment is underway, but achieving
the mission for interoperability will be a series of actions on multiple fronts,
at different times. Not only does the Enhanced Certification Program aim to
greatly improve the quality of existing OPC products, it must also ensure the
interoperability of products developed on the new OPC UA specifications. The
scope of OPC UA products extends throughout the enterprise, and will present
even more interoperability challenges. Significant resources from the OPC
Foundation member companies have been committed, and the necessary processes,
specifications and tools that will serve as the foundation for certifying all
OPC products, including OPC UA, are being developed. The inevitable outcome of
the OPC Foundation Enhanced Certification Program is the establishment of a
testing methodology that ensures secure, reliable and interoperable high-quality
OPC solutions for the end-user community, now and in the