Glossary of Terms

  • Absolute Pressure : Pressure measured relative to high vacuum, often measured in PSIA(Pound per Square Inch, Absolute), or in Torr. Full vacuum is 0 PSIA or 0 Torr, atmosphere is about 14.7 PSIA or 760 Torr.
  • Accuracy: Combined error of non-linearity, hysteresis and non-repeatability. Often use RSS (Root Sum of the Squares) method.
  • Atmospheric Pressure: The force exerted per unit area by the weight of the atmosphere.
  • Barometric pressure :  Atmosphere pressure measured relative to high vacuum, often measured in millibars. Atmosphere is about 1013 mbar.
  • Differential Pressure:Pressure measured relative to a reference side, often measured in PSID(Pound per Square Inch, Differential), inch of water column or in Pascal.
  • DIN: Deutsches Institut für Normung e.V., The German national organization for standardization and is that country’s ISO member body. DIN and mini-DIN connectors, as well as DIN rails are several examples of older DIN standards that are today used around the world.
  • Gage Pressure : Pressure measured relative to ambient atmosphere pressure, often measured in PSIG (Pound per Square Inch, Gage), or in Pascal.
  • Humidity: The amount of water vapor in a given volume of air or gas.
  • Hysteresis: The maximum output difference at any pressure point, when the point was reached first by increasing pressure and then by decreasing pressure.
  • Manual Reset: A control that must have human input before it will return to its normal state from an alarm state.
  • NEMA: The National Electrical Manufacturers Association, a trade association in the US of electrical equipment manufacturers that develops many industry technical standards, such as the standard for electrical equipment enclosures..
  • Non-Linearity: Sometimes referred to as linearity. It is the maximum deviation of the output at any pressure points comparing with a straight line.
  • Non-Repeatability: Sometimes referred to as repeatability. It is the maximum output difference at any pressure point, when the pressure is applied under the same condition.
  • Range: The span of rates within which the sensing element of a given switch can be set to actuate an electric switch.
  • Rated Pressure: The maximum pressure that the actuating components of the switch in contact with the media can withstand continuously and/or repeatedly without risk of permanent damage.
  • Response Time: The time it takes an element to respond to a change in the value of the measured variable or to produce a change in the output signal.
  • Span: The difference between the highest and lowest numbers in a range.
  • Span Temperature Coefficient: The maximum amount the span reading could change at any point within the compensated temperature range. This error is typically expressed as a percentage of full scale output of reading. It can also be expressed as percentage of full scale per °C, °F or K e.g. ±0.02%FS/°C.
  • Static Pressure: The pressure exerted by a fluid at rest. The outward push of a fluid against the walls of a container.
  • Temperature Compensation: The correction for the influence of temperature on a measurement.
  • 3-A: 3-A Sanitary Standards Inc., A non-profit association representing equipment manufacturers, processors, regulatory sanitarians, and other public health professionals that creates standards and accepted practices for dairy and food processing equipment and systems.
  • Total Pressure: The sum of velocity and static pressure.
  • Vacuum Pressure: Pressure measured relative to ambient atmosphere pressure, often measured in PSIV (Pound per Square Inch, Vacuum). Atmosphere is 0 PSIV, full vacuum is about 14.7 PSIV.
  • Zero Temperature Coefficient: The maximum amount the output reading at zero pressure might deviate over the compensated temperature range. This error is typically expressed as a percentage of full scale output of reading. It can also be expressed as percentage of full scale per °C, °F or K e.g. ±0.02%FS/°C.

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