Читать книгу Automation of Water Resource Recovery Facilities - Water Environment Federation - Страница 210

Step control provides control response in discrete steps or levels. An example of step control is a pump station with constant speed pumps. Possible steps in a two-pump station are listed in Table 7.1.

Step control is advantageous because it is simple and it eliminates the cost of variable control equipment; however, it does result in more variability. For example, the pump station will keep the level within a range, but it cannot control precisely enough to keep the level constant. This is likely not necessary for lift stations; however, for many control applications, more precise control is needed.

TABLE 7.1 Possible steps in a two-pump station.