Setup
Filtration Learning System
26
© Festo Didactic
696684
8.3
Function of the pressure control system
The process pressure of a gas in a filter system must be regulated. The pressure control system is a
controlled system with low compensation (PT1).
During the rinsing process, the filter FL1 is blown free with controlled compressed air. In the control circuit,
the proportional pressure regulator VC1 works as a final control element. First, air is blown in at low
pressure. Air is then blown in at a higher pressure until the pressure and time of the recipe are reached. The
pressure is detected by a pressure sensor BP1 and converted into an electrical signal.
Figure 4: Pressure control system – Filter FL1, proportional-pressure regulator VC1 and pressure sensor BP1 (PCE task "PIC BP1")
The pressure in the filter housing FL1 is generated by proportional pressure regulator VC1. The system
pressure is measured with a BP1 piezoresistive pressure sensor at the PCE task "PIC BP1" as controlled
variable and should be kept constant even after faults or changes in the reference variable.
A 0…10 V analog control signal determines the output value of the proportional pressure regulator with
integrated control electronics as the manipulated variable.
Backwashing acts as a disturbance variable if additional water is pumped back through the filter.
