WIKA PSD-4 - Switching Functions Explained

14208834.01 07/2017 EN/DE/FR/ES
19WIKA operating instructions pressure switch, model PSD-4
EN
5.9 Switching functions
Hysteresis function
If the system pressure uctuates around the set point, the hysteresis keeps the
switching status of the outputs stable. With increasing system pressure, the
output switches when reaching the switch point (SP).
■
Contact normally open (HNO): Active
■
Contact normally closed (HNC): Inactive
With system pressure falling again, the output will not switch back before the reset
point (RP) is reached.
■
Contact normally open (HNO): Inactive
■
Contact normally closed (HNC): Active
Window function
The window function allows for the control of a dened range.
When the system pressure is between window high (FH) and window low (FL),
the output switches on.
■
Contact normally open (FNO): Active
■
Contact normally closed (FNC): Inactive
When the system pressure is outside window high (FH) and window low (FL), the
output does not switch on.
■
Contact normally open (FNO): Inactive
■
Contact normally closed (FNC): Active
Fig.: Hysteresis function
Fig.: Window function
5. Commissioning, operation
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