Monday, September 9, 2013

Automation Software: Pick OPC to be more Futureproof

When scoping out automation projects, we commonly run into the tension of cost versus extensibility.

A system that is "futureproof" is one that can withstand changes to requirements or specifications that are determined at some later time. As with a lot of decisions in life, choosing a short-term gain often comes at the expense of the long-term.

So is the case when deciding to go with OPC at a greater initial cost. OPC stands for "OLE for Process Control" where "OLE" is Microsoft terminology that stands for Object Linking Embedding. (I guess that would make OPC short for "Object Linking Embedding for Process Control.")

OPC Foundation logo As discussed here and here, OPC is the standard for communications between automation systems. OPC is maintained by the OPC Foundation… an industry consortium and is essentially what makes vendor agnosticism possible.
Vendor Agnosticism
Not having to believe in or commit to or be beholden to a single vendor.
For example, suppose you want to go with a Rockwell system. Rockwell has an embedded historian called, "FactoryTalk." Under the hood, FactoryTalk is OSIsoft PI. Side-by-side, they share the same folder structure, the same commands, the same services.

So the logical thing to do when setting up a corporate PI system is to buy a PItoPI interface and call it a day, right?

Not so fast.

Suppose the facility has a Building Automation System (BAS) and while out-of-scope for this project, the data from the BAS is expected to go into this corporate PI system. What happens then?

One option is to find that specific BAS vendor and see if OSIsoft sells a PI interface for this BAS vendor.

A second option is to see if this BAS vendor sells an OPC server for their data and if so purchase the OPC server and purchase the OPCtoPI interface and connect the two via OPC.

What happens if another control system enters the picture (suppose a Finesse/DeltaV system was purchased and commissioned)? The same questions have to get asked again (and re-answered).

Futureproofing in this case means choosing OPC and running every new system through this standard of communication, even at a greater cost to the initial system. In short-term, there is a larger budget to justify; in the long-term you eliminate future work (Design Reviews, meetings, revisiting past decisions…)

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