Switching Functions; Hysteresis Function; Window Function - WIKA PSD-4-ECO Mode D'emploi

5. Commissioning, operation

5.9 Switching functions

Hysteresis function

If the system pressure fluctuates around the set point, the hysteresis keeps the
EN
switching status of the outputs stable. With increasing system pressure, the
output switches when reaching the switch point (SP).
Normally open contact (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.
Normally open contact (HNO): Inactive
■
Contact normally closed (HNC): Active
■

Window function

The window function allows for the control of a defined range.
When the system pressure is between window high (FH) and window low (FL),
the output switches on.
Normally open contact (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.
Normally open contact (FNO): Inactive
■
Contact normally closed (FNC): Active
■
20
Fig.: Hysteresis function
Fig.: Window function
WIKA operating instructions, model PSD-4-ECO