Pressure Switch Glossary
Absolute Pressure – The difference between zero pressure and a known pressure.
Adjustable Range – Pressure range within the actuation point that a pressure switch may be adjusted.
Adjustable Set Point (AP) – Allows the user or manufacturer to change the set point (make or break) to any pressure setting within the operating band of the switch.
Alternating Current (AC) – An electric current that reverses its direction at a given time interval.
Ambient Pressure – Adjecent pressure, not necessarily atmospheric, immediately surrounding and influencing an uncompensated pressure actuated switch.
Ambient Temperature – Surrounding temperature conditions (not necessarily atmosheric conditions).
Break – The point at which the electrical contacts open to disconnect a circuit.
Burst Pressure – The maximum pressure which may be applied to a switch without causing leakage. Permanent degradation may occur or the unit may become inoperable if burst pressure is exceeded.
Current – The flow or transport of electric charges along a path or around a circuit.
Deadband – The difference between actuation and deactuation points of the electrical contacts of a pressure switch.
Differential Pressure – The difference betweeen a reference pressure and a variable pressure.
Factory Set Point (FS) – The pressure switch is calibrated and sealed at Endura, so that the set point can not be adjusted without breaking the seal.
Fixed Set Point (FP) – The pressure switch has a certain operating band that cannot be changed.
Hysteresis – The phenomenon by which an effect in a component depends not only on the present stimulus, but also on the previous state of the component.
Make – The point at which the electrical contacts close to complete an electrical circuit.
Maximum System Surge Pressure – The MAXIMUM pressure including “spikes” that a system may be subjected to.
Pilot Duty – A load of power factor and high inductive typical of solenoid coils or heater contactor coils.
Pressure – The force exerted over a surface divided by the area of that surface.
Pressure Fall Set Point – The control set point is actuated at a decreasing positive or negative pressure.
Pressure Rise Set Point – The control set point is actuated at an increasing positive or negative pressure.
Pressure Switch – An instrument that senses a change in pressure and actuates an electrical switching element when a pre-determined pressure point is reached.
Repeatability (Accuracy) – The ability to consistently maintain a given set point calibration for a set of environmental and operational conditions.
Resistive Load – An electrical load in which voltage and current are converted to energy in the form of heat; i.e., an electrical heater.
Sample Line Fittings – Pressure connection to the switch pod.
Set Point – The exact pressure at which the electrical circuit controlled by the pressure switch changes contacts. A pressure switch may have a set point on either pressure rise or fall, but not both.
Set Point Tolerance – The maximum allowable setting deviation between two or more production units under all specified environmental conditions.
Snap Acting Switch – A mechanically operated electric switch having predetermined and accurately controlled characteristics.
SPDT – A Single Pole Double Throw switch has a common, normally open and normally closed terminals. A single type switch used to control one circuit load.
SPST – A Single Pole Single Throw switch has a common terminal and either a normally open terminal (SPNO) or a normally closed terminal (SPNC).
Steady State Operating Pressure (Working Pressure) – The normal pressure of a system which DOES NOT include the maximum surge the system may be subjected to.
Switch Differential (Deadband) – SEE DEADBAND.
Test Point (sample point or pick-up point) – Point at which a pressure tap is located on the unit to feed the signal.
Tolerance – The normal variation in the production of pressure switches of the same model and set point. It affects the actuation value and the reactuation point.
Transducer – A device which converts energy (pressure) from one form into another (electrical output), always retaining the characteristic variations of the energy being converted.