Introduction to Industrial Automation

3.5.2   Pump Operation Based on Level Control

One pump is utilized to transfer water from a watering channel to a tank A, which should be kept 

continuously full, as presented in Figure 3.25. In this example, the operation of the pump should 

be fully automatic. With the help of an electronic level switch (ELS) as a controller, it is possible to 

keep the level of the tank between the levels E

1

 and E

2 

constantly without any human intervention. 

This is achieved through the simple automation circuit also displayed in Figure 3.25.

For a full understanding of this operation, recall the operation of the ELS as presented in 

Section 2.2.5, and more specifically the change of the output function of ELS (SPDT contact) 

with respect to the level change. With a similar automation approach, we can understand a case 

where a pump, through continuous operation, supplies water from a tank to a water network, as 

long as the tank contains water.