Relays Models 680 Nullmatic Biasing Relays Introduction Features & Benefits Rugged design delivers load splitting for control circuit flexibility Powder coating provides improved corrosion resistance Description The Model 680 Nullmatic Biasing Relay is used to apply plus or minus bias to an instrument input signal. It is typically used in load splitting, setpoint biasing, and override control applications. Specifications Input & Output Range Normal: 3 to 15 psig Maximum: 0 to 50 psig Bias Adjustment ±18 psig Supply Pressure Normal: 20 psig Minimum: 5 psi above desired output Maximum: 55 psig Ambient Temperature Limits -40 to 180°F (-40 to 82°C) 7 7.38 Mounting Dimensions