Which type of signal is frequently used in control systems to represent process measurements?

Analog signals are frequently used in control systems to represent process measurements because they provide a continuous representation of the measured variable. This allows for a more precise and nuanced view of changes within the process, as analog signals can vary smoothly over a range of values rather than just switching between defined states. For example, temperature, pressure, and flow measurements are typically represented by analog signals, enabling the control system to react to subtle changes in these variables.

In contrast, while digital signals are important in many modern systems due to their reliability and noise immunity, they generally represent discrete levels or states. This can limit their effectiveness for capturing the full variability of continuous processes. Pulsed signals and square waves, on the other hand, are specific forms of digital signals which, while useful in particular applications, do not effectively capture the nuances of continuous measurements inherent in many control system environments. Thus, analog signals remain the preferred choice for accurately representing process measurements in these systems.