The question arises quite often, “What is the normal or standard form of the PID (proportional-integral-derivative) algorithm?”

The answer is both simple and complex. Before we explore the answer, consider the screen displays shown below (click for a large view of example 1 or example 2):

As shown in the screen displays:
▪ There are three popular PID algorithm forms (see step 5 in the large image views).
▪ Each of the three algorithms has tuning