Dear Colleagues

As most of you would know, the so-called black box is a fundamental building block for engineering design. Indeed, it is used for many other activities where we simply refer to the ‘black box’.

What is a Black Box?
This is a conceptual container where we feed in inputs and get outputs emerging from a so-called black box. We don’t worry about how these outputs are derived as this is all dealt with by the ‘black box’. It means we don’t need to fret about what actually happens in the black box. Often, supremely complex processes are involved in the black box and this could be hard work to unravel about precisely what is going on.

The Black Box works well with Multidisciplinary Teams
The output of one team serves as the input for other teams. For example, in a plant construction project the civil engineering team will feed through their design outputs to the mechanical, electrical and instrumentation teams. Who in turn will feed through their outputs through to the next series of teams (IT, telecommunications and so forth).

It Works well for explaining difficult concepts
When explaining a difficult process control concept – for example how a Process Control Loop Controller works; it is best to simply to say the Process Variable and Set Point feeds into the PID Black Box and this is what the control output looks like coming out the other end. We aren’t that interested in the actual activities of the integral, derivative lead and lag algorithms inside the black box; but more in the practical output results of the controller.

Similarly, an electrician wiring up a complicated Programmable Logic Controller (PLC) treats this as a ‘black box’. She knows there will be inputs to the PLC “Black Box’ and outputs to control the plant. But she doesn’t need to know what is happening in the PLC itself.

In the Real World we are all humans and work in a web of interrelated relationships
In the real world, the black box approach doesn’t always work as neatly as this. We all work in a complex web of relationships with real world constraints. Projects rarely go to plan. Bad weather, supply problems of components, staffing issues and client changes impact on a daily basis.

You Thus Need to be Dynamic
So, while the black box is a great idea and nice to have in simplifying the overall system; be alert to the real dynamics of the world. Watch out for opportunities to improve your processes and be alert to threats to the design and installation.

For example, the electrician may see some changes happening in the processes of the plant and has to request program changes to the PLC Black Box to ensure she does get the outputs required.

A good way of persisting with whatever you are doing is to follow Jonathan Winters remark: I couldn't wait for success, so I went ahead without it.

Ideas for this blog came from a great eminently readable book: 101 Things I learned in Engineering School by John Kuprenas and Matthew Frederick.

Yours in engineering learning,


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