By Eric Murphy, ControlGlobal.com Columnist
Anyone familiar with OPC will have heard about the OPC Foundation’s OPC Product Certification process. The program raises the bar on OPC compliance and aims to improve OPC product interoperability. As the process rolls out, people are asking questions: “What does it do for me?”; “Isn’t Compliance good enough?”; “Why bother?” Vendors shouldn’t be complacent with just Compliance (or just Certification for that matter). Why not? Let’s ask some questions and find out.
What is Certification?
The OPC Enhanced Certification Program comprises a multiple-phase process which ensures OPC products are reliable and interoperable with other automation suppliers’ products. The process comprises self-testing of products using OPC Foundation-supplied compliance testing tools, OPC Interoperability Testing sessions with other vendors, and third-party independent OPC Certification system testing. The results of the process for each vendor’s product are easily identified by OPC Foundation Certification logos and are searchable on the Foundation website.
Who Benefits, and How?
The obvious beneficiaries are the end users. Compliance testing ensures OPC servers conform to the basics of the interface specifications and should operate as expected. All OPC Servers are tested against the same compliance tool, and need to perform as outlined the specifications. Granted, users will never be using the compliance tool client in their production environment, but testing ensures OPC servers are behaving as they should.
Interoperability Testing gives the user confidence the OPC server or OPC client is compatible with other OPC products, and has been tested beyond the functionality outlined in the specifications. Industrial-grade OPC products typically support an additional level of expected functionality that is also validated during these test sessions. These workshop sessions demonstrate that a particular OPC vendor’s product has successfully communicated with multiple OPC implementations ranging from competitor’s products, testing tools, generic applications, and specialized OPC functionality products. OPC vendors who participate in the Interoperability sessions often represent majority market-share holders in OPC products, control systems and industrial automation applications.
Finally, the Independent Certification testing incorporates and extends the testing outlined at the Compliance and Interoperability levels. This impartial, third-party testing provides end users with a comparable, ‘apples-to-apples’ level of test results. The testing at this level enters into the realm of ‘real world’ environments and adds 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.
In order for certification to be successful, vendors must also see the benefits of going through the process. First off, participation implies OPC Foundation membership, and membership has its privileges, including access to testing tools, debug support and quality assurance. The key benefit to OPC Compliance testing is access to self-certification and testing tools to validate the correct implementation and interpretation of the OPC specifications. Successful testing also allows for the use and display of the OPC Certification logos, which signify a quality product. OPC vendors also gain marketing benefits via listing in the OPC Foundation product catalog and website.
Interoperability Testing gives vendors access to additional testing tools as well as the opportunity to validate their products against a wide range of OPC products, including direct competitors. The Interoperability sessions not only offer a chance to verify the correct operation of vendor products, they are also a chance to see what other products offer and how they perform.
Beyond the obvious marketing benefits of achieving a higher level of OPC Certification, the independent test labs offer OPC vendors opportunities for additional testing. The comprehensive test lab coverage provides system-level testing, error-handling scenarios, and unbiased enterprise integration testing. The more any product is tested the better it becomes, and the less money will be spent after the fact on correcting issues. Experience shows an unresolved bug grows exponentially in cost the later it is detected and rectified.
How Much is Enough Testing?
OPC Foundation has raised the interoperability bar significantly. The certification process will improve overall interoperability, but that doesn’t mean all products are created equal. Increasing the baseline testing process will not stifle innovation or best-in-class achievement, and there will still be those vendors that will do more to stand out from the crowd. The OPC Foundation has provided the tools and the format, but ultimately it’s the vendors who must assume responsibility for interoperability. It is the individual vendors who need to state "My product works in a production environment with systems X, Y and Z.” In addition to meeting the stringent process outlined by the OPC Foundation, committed OPC vendors will step up and cooperate with each other. This cooperation will include vendor partnerships, production-level testing environments and continual OPC testing as product lines develop.
Where Does this Leave Us?
OPC Certification leaves end users with more confidence in product interoperability. However, just as with OPC Compliance today, OPC Certification should really be the minimum vendors strive for. The OPC Certification program creates a solid quality baseline for interoperability that separates the wheat from the chaff. Serious vendors will strive for the highest levels of Certification and beyond, and serious end-users will demand nothing less.