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Differential pressure detection
Filter monitoring (monitor degree of soiling)
• The pressure sensor (1) detects the system pressure P1 in front of
the filter (2).
• An external sensor (3) with analogue output (4 ... 20 mA) detects
the pressure behind the filter P2.
• The differential pressure P1 - P2 indicates the degree of soiling. As
soon as it has exceeded 0.3 bar, the pressure sensor (1) provides a
signal (output1 = ON) that filter maintenance is necessary.
Wiring diagram:
→
→
example 2, page 25
.
30
SP1 = 0.3
OU1 = Hno
Output 1 is to switch (= ON) when the differential pressure
exceeds the value of 0.3 bar.
InP2 = I
The external sensor provides a current signal.
ILP2 = 4.00 For 0 bar the external sensor provides 4 mA.
IHP2 = 20.00 For 5 bar the external sensor provides 20 mA.
IEP2 = 5
Final value of the measuring range of the external sensor.
SP1
= 0,3
Display: Dmod = P1-2: differential pressure P1 - P2 is displayed.
differential pressure P1-P2 caused by the filter in bar
permissible degree of soiling
degree of soiling of
the filter
1
OUT
3
2
