OPC Foundation counters infringement lawsuit filed against end-users

In a recent statement to its members, the OPC Foundation expressed disappointment that Solaia Technologies LLC (Chicago, Ill.) filed a patent infringement lawsuit last year against several customers of OPC members.

Solaia filed its patent infringement lawsuit on Aug. 27, 2001, in the Northern District of Illinois in Chicago against Jefferson Smurfit Corp., The Clorox Co., Konica Corp. and BMW. The suit alleges infringement of U.S. Patent 5,038,318, entitled “Device for Communicating Real-Time Data between a Programmable Logic Controller and a Program Operating in a Central Controller.” It is also known as the “318 patent.”

The 318 patent was filed by Square D Co. (Palatine, Ill.) on Dec. 17, 1987. Solaia has stated that it acquired the 318 patent from Square D in an auction held in early 2001. Square D is owned by Schneider Electric (Paris, France).

OPC also expressed “great shock and disappointment that Solaia is now alleging that automation systems using DDE servers, OPC servers, and spreadsheet programs to interact with programmable logic controllers or other manufacturing automation equipment are likely covered by the claims of the 318 patent.”

OPC Foundation believes that the case is without merit. The text of the foundation’s stated argument is as follows:

“In documents filed with the court, Solaia argues that its patent is entitled to very broad coverage that could extend to a variety of systems. However, we think that the best indicator of what the patent covers can be found by looking at the language of the patent itself, along with the arguments that the applicant made to convince the U.S. Patent Office to issue the patent in the first place. These are all public documents, which anyone can review.

“The description of the 318 patent sheds light on what the inventor considered his invention to be. Importantly, the 318 patent states, ‘The invention furnishes a program or instruction means that operates through a general purpose spreadsheet program to effect information transfers to and from the addressable registers of a PLC and assigned cells of a displayed spreadsheet directly from the spreadsheet program and without transfers through the operating system program or a specially written device driver program.’

“When the patent was pending in the patent office, the applicant made a significant argument to convince the examiner that he should receive a patent. The applicant argued: ‘That is, the link is direct and always present. There is no message exchange between the applications before a transfer of information occurs. The transfer of data is direct between addressable registers in the PC and addressable registers in the PLC. Operation is directly from the spreadsheet program in the PC to the application in the PLC to effect information transfer. There are no intermediate transfers through the PC’s operating system or special device driver programs. The DDE steps of initiate, acknowledge connect, transfer, and disconnect are not required. The client server model does not exist.’

“If the 318 patent is limited by the statements in the description and the arguments made to the examiner, then the patent can only cover systems using a direct interface, without passing the data through the operating system, device drivers or a client-server model to exchange data.

“There are other limits on the 318 patent. From the inventor’s arguments above, it is apparent that DDE and DDM systems are not covered by the patent because: (1) they were known before the 318 patent was filed; and (2) DDE and DDM were expressly distinguished from the invention in the arguments to the patent office and the description in the patent. DDE and DDM both require information to be handled by the operating system, and DDE makes extensive use of the client-server model. Thus, DDE and DDM systems would not be covered by the 318 patent.

“OPC systems similarly require use of a client-server model, and the overwhelming majority of OPC systems use a typical client server model in which the movement of information between client and server requires exchange of messages using operating system services. Importantly, most OPC systems were developed using an OPC server resident on a separate computer from the OPC client. For the same reasons that DDE systems are not covered by the patent, OPC systems using messaging and operating system services to effect information transfer between client and server also would not be covered.

“All of the claims of the 318 patent require a ‘spreadsheet means’ or ‘spreadsheet instruction means.’ There is no suggestion in the patent that any other application layer interface or human-machine interface (HMI) be used, other than a spreadsheet. For example, the patent does not suggest anywhere that the invention includes substitution of a database management system for the spreadsheet. Nothing in the patent text suggests that the claims cover systems that do not include a spreadsheet or another program very similar to a spreadsheet.

“We are not aware of any systems made or used by OPC Foundation members that we believe infringe the 318 patent. We certainly would never advise anyone to infringe a patent. However, the OPC Foundation is not in a position to dispense legal advice to its members. A given member’s position with respect to the 318 patent may differ from that of other members, in light of specific factual or legal issues of which we have no knowledge. Therefore, the OPC Foundation (and its counsel) must necessarily disclaim any responsibility to any member who relies on this summary in making its own decisions or in taking its own actions with respect to the 318 patent. The best way for our members to develop OPC based systems while avoiding any conflict with the 318 patent is to learn about the patent itself, to learn about the OPC standard, and to maintain awareness of how your own system differs from what the patent claims.”

Author Information

Gary Mintchell, senior editor gmintchell@cahners.com

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