Control challenge

Two typical setups of the tanks described previously are shown in Figure 4.1:

Figure 4.1 – Tanks with level sensors for measuring the level of fluid

In industry, the levels in tanks are measured using sensors. In the preceding figure, we show two possible setups to measure levels. In the image on the left, the tank has two outlets connected with a transparent pipe. Sensors are placed near the pipe at three different levels—top, bottom, and middle. Depending on the application and the factory’s need to monitor the level precisely, additional sensors could be connected to the pipe—near the top (90%), at 75% and 25%, and near the bottom (10%). The measuring accuracy itself is high but the programmer, user, and operator get visibility of only three or four levels, depending on the number of sensors selected. If the operator misses the warning at 25%, then the next level about which they will be alerted is 10%,...