Omega VDC PSW20B, Vdc Vac, Pressure Switching Normally Closed Contacts, Vacuum Switching

		Standard			Repeat
Part		Electrical rating			Accuracy	Contact
Number		Max.		Min	Constant	Resistance
		Resistive	Resistive		Temperature	(ohms)
PSW20A		750ma		5 ma	+/- 4%	0.04
		250VAC	3 VDC
PSW20B		1 amp		5 ma	+/- 3%	0.02
		250	3 VDC
		VAC
	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.