Fear of darkness: Integrating automation systems to a more complex protocol converter
One task I am commonly asked to perform is to redesign a system to eliminate the aptly named “black box”. As most readers of this blog know a “black box” is the generic term for a protocol converter. Originally, these devices only converted electrical protocols, for example RS-232 to RS-485. They were named because no one knew how the magic took place in the “black box”. If these boxes remained solely electrical protocol converters, I don’t think that my services would have much value to our clients. These original “black boxes” ran for years without any user intervention or maintenance requirements.
Times change and as automation systems became more complex and data interfaces became more important each manufacture had their own protocols. Almost all were electrically and structurally different. The need to integrate all these automation systems required a much more complex protocol converter. The “black boxes” had become essentially computers communicating to each automation system with a compatible protocol.
One distinguishing feature of these devices is that they are programmed in a language that is not directly shared by either automation system, therefore not configurable by the in house controls engineers. This is the reason clients are looking to eliminate these boxes. It requires a third party to make changes to the data transfer between two automation systems. More often than not the engineer that can program the “black box” is the pipe smoking UNIX programmer found in the Dilbert cartoon. This person may or may not have documented how the magic happened and this person is nowhere to be found after the box was installed. Essentially preventing the system from being modified for changing process conditions.
As the boxes have become more complex, they have migrated from defined purpose hardware and software to commercially off-the-shelf (COTS) hardware, using a Microsoft operating system and a custom software application. While on the surface this seems a great solution, eliminating the need for the pipe smoking UNIX programmer, it has made the boxes subject to the rapidly changing commercial market. Sometimes black box hardware becomes difficult to replace in as little as four years due to incompatibility of new hardware with an older operating system. In addition, with the advent of cyber security threats these “black boxes” now need to be updated, virus protected, and validated to ensure they do not become an attack vector to an automation system.
What do we advise when asked by our clients to help them out of their box? We advise they step back and look at the larger picture. Does all the data need to be routed through the automation system? Can separate data collection systems be installed that will provide a separate path that eliminates the need for a “black box”? Depending on the data needed, even an old discrete 4-20 milliamp analog signal from one system to another might fit the bill. Do you really need a full data interface and “black box” to get the temperature from your weather station into your automation system? If systems must be integrated, the ability to integrate them without a “black box” should rank much higher in the system selection then generally practiced over the last 20 years.
Fear of darkness is not necessarily a bad thing. It might lead you to install an automation system that is easier to install and maintain for years to come.
This post was written by Bruce Billedeaux. Bruce is a senior consultant at MAVERICK Technologies, a leading automation solutions provider offering industrial automation, strategic manufacturing, and enterprise integration services for the process industries. MAVERICK delivers expertise and consulting in a wide variety of areas including industrial automation controls, distributed control systems, manufacturing execution systems, operational strategy, business process optimization and more.
MAVERICK Technologies is a CSIA member as of 3/20/2015