WIKA PSD-4-ECO, Operating Instructions Manual

Page: 20 / 140

14247391.01 07/2019 EN/DE/FR/ES
20 WIKA operating instructions, model PSD-4-ECO
EN
5.9 Switching functions
Hysteresis function
If the system pressure fluctuates 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).
■
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
Fig.: Hysteresis function
Fig.: Window function
5. Commissioning, operation