When the idea of "open" bus communications systems first surfaced in the automation industry back in the 1980s, suppliers, original equipment manufacturers, and end users alike embraced the idea as something revolutionary.
And indeed it was. The prevailing wisdom was that open systems would give customers supreme flexibility with their automation systems, allowing them to select their components from more than one supplier. These systems were intended to be "interoperable", meaning that all the components, no matter what their source was, would work harmoniously together to provide a best-in-class technology solution for the customer.
Unfortunately, the dual concept of open and interoperable hasn't been executed as it was originally conceived. Today, single-vendor solutions are often disguised as open systems, leveraging a single control vendor's network, and giving access exclusively to non-competitive partners. This allows an entrenched relationship between supplier and customer to continue, while masquerading as an "open" solution.
So, when evaluating open and interoperable control systems, a good question to ask is: "How many vendors are developing control systems for this bus network?"
Furthermore, some suppliers say they adhere to the open concept, but fail to adhere to interoperability. Supplier A says it embraces openness, then proceeds to shut out competitive Suppliers B, C, and D from providing the best possible solution for the customer by promoting a "controlled open" solution that is really just one company's version of an open bus.
The open-interoperability concept has been twisted in other ways as well. For example, even when all suppliers agree to an open solution for a particular application, Supplier A can thwart the other suppliers' efforts by specifically writing code that only allows communication with their own products. That's not looking out for the customer's best interests—and it's certainly not in the spirit of the open-interoperability concept.
One of the more popular myths in the industry is that customers aren't concerned about openness. All they want is a single configuration, access to drive information, high and guaranteed performance, and insured drive and control compatibility.
Nothing could be further from the truth. Customers want all of these things, but the true value in an open network is interoperability, to ensure that customers get the very best solution for their particular application. In fact, recent surges in open system requests indicate that open and interoperability are a perfect marriage.
The bottom line in this whole matter is this: The customer, not technology suppliers, should decide what's best for his particular application. In my experience, most—if not all—customers desire a best-in-class technology solution chosen by them, not forced by a technology supplier. To achieve that kind of solution, their systems must be open and interoperable.