I recently had an interesting exchange with an Automation World reader over use of the word “control” in industrial applications. I didn’t ask if I could use his name, but he is a control engineering professional.
He took exception to a couple of articles that appeared on the magazine Website. One was an announcement regarding an upcoming seminar from a company called Inductive Automation. This company has a product that is Software as a Service and bills it as SCADA.
From the reader, “OK, you guys keep advertising yourselves as ‘SCADA’ software. The ‘C’ stands for ‘Control’. Your software does not have control capabilities so therefore it is not SCADA. Until there is no PLC between you and the process then you are not SCADA.“
I love these comments, because they make me think. Be honest, when is the last time you thought about control and its definition? Interestingly, that same day Eric Byres posted to his SCADA Security blog on the idea of defining various types of control.
Here is some of my response, “I’ll let Inductive Automation people answer for themselves as far as its product goes.
“SCADA is, of course, supervisory control and data acquisition. Historically that comes from monitoring remote applications (wastewater, pipelines, remote installations) that have some local distributed control (not DCS) that has taken the form of RTUs but recently have become much more powerful. SCADA typically just does supervisory control with default control going to the local loop controller.
“However, as this article published just today on the SCADA security blog points out, the blurring of technologies has caused a nomenclature (how you describe) problem for the industry.
“My experience is that the application grew up to maturity as a software solution blended with various types of networking (point-to-point radio, cellular, Ethernet to landline, etc.).
Here are some of Eric’s thoughts. Visit the Web page for his complete analysis. “Now the quick answer is that Supervisory Control and Data Acquisition (SCADA) is a subset of Industrial Control Systems (ICS). SCADA generally refers to control systems that span a large geographic area, such as a gas pipeline, power transmission system or water distribution system. I use both terms together because SCADA is often better known by the press, government officials and the public, but ICS is probably the technically correct term to use if you are referring to industrial automation of all types.”
Eric’s analysis is that microprocessor technology advancements are causing a blurring of the lines among the various types of control in industrial applications (DCS, PLC, SCADA). I think he’s right. He’s pushing the term “Industrial Control System” as the basic term to cover them all. That is common in security circles currently. Perhaps we all need to pick up on that.
I'm going to disagree with your other reader's definition of SCADA. While the C does indeed stand for Control, it's not on its own. It's "Supervisory Control." In other words, things like starting and stopping a process, or loading recipes. So SCADA systems are still SCADA systems when they talk to PLCs or RTUs without doing any direct communication to field devices. If press "Start" on a SCADA screen, and 30 pumps kick on, I would call that Supervisory Control, regardless of whether there are other "brains" that more directly control those pumps.
Sage Automation, Inc.
Thanks for the update, James.