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1. The Excitement of Control Engineering

1.5.3 Sensors

Sensors are the eyes of control enabling one to see what is going on. Indeed, one statement that is sometimes made about control is: If you can measure it, you can control it. This is obviously oversimplified and not meant literally. Nonetheless, it is a catchy phrase highlighting the fact that being able to make appropriate measurements is an intrinsic part of the overall control problem. Moreover, new sensor technologies often open the door to improved control performance.

Alternatively, in those cases where particularly important measurements are not readily available, then one can often infer these vital pieces of information from other observations. This leads to the idea of a soft or virtual sensor. We will see that this is one of the most powerful techniques in the control engineer's bag of tools.