Omega PSW20 - Manual (Page 2)

Standard
Electrical rating
Repeat
Accuracy
Part
Number
Max.
Resistive
Min
Resistive
Constant
Temperature
Contact
Resistance
(ohms)
PSW20A 750ma
250VAC
5 ma
3 VDC
+/- 4% 0.04
PSW20B 1 amp
250
VAC
5 ma
3 VDC
+/- 3% 0.02
Body Acetal
Diaphragm EPDM is standard; Nitrile
available. NOTE: EPDM should
not be used in petroleum
applications
Contacts Gold plated silver
Springs Plated phosphor bronze
Terminals Plated copper or brass
Adjusting screw Stainless steel or zinc plated SS
Weight 9 grams (0.3oz)
Operating temperature -30 C to +65 C (-23F to 149F)
Listings UL recognized for 100,000
operations
CSA certified
Connections and Adjustment
Pressure Switching – Normally Open Contacts
Connect the pressure source to inlet port B (see diagram) and set the adjusting screw to the desired pressure.
Turning the screw clockwise narrows the gap between contacts and decreases the pressure set point. Turning the
pressure adjusting screw counterclockwise increases the set point. Note: the media entering the
diaphragm through Port B is separated from the electrical contacts by the diaphragm.
Pressure Switching – Normally Closed Contacts
Connect the pressure source to Port A and monitor continuity across the terminals. Slowly turn the adjusting
screw clockwise, narrowing the gap between contacts until the contacts are closed. Apply the set point pressure
which will open the contacts. Continue to turn the adjusting screw clockwise until the contacts
make and break at the desired point.
Vacuum Switching
Repeat the above procedure using Port A for Normally Open Contacts and Port B for Normally Closed
Contacts.