ASTM: (Formerly known as The American Society for Testing and Materials) An international standards developing organization that develops and publishes voluntary technical standards for a wide range of materials, products, systems, and services.
气压: The force exerted per unit area by the weight of the atmosphere.
英国热门单位（BTU）: The amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. Melting a pound of ice at 32°F requires 143 BTU.
BSPT: British Standard Pipe Thread.
Capacitance: A measure of the amount of electric charge stored (or separated) for a given electric potential. The most common form of charge storage device is a two-plate capacitor.
闭环: A control system that provides feedback to a controller on the state of the process variable.
冷端: The end of thermocouple that is kept at a constant temperature in order to provide a reference point.
Critical Pressure: The ratio of upstream to downstream pressure where the gas velocity out of the valve is sonic and further decreases in downstream pressure no longer increase the flow.
Derivative Control: A method of changing the output of a controller in proportion to the rate of change of the process variable.
露天: The temperature to which air must be cooled for the air to be saturated with water.
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.
Direct Current (DC)：具有恒定极性的电流。
双极双掷（DPDT）开关: Two separate switches that operate simultaneously, each with a normally open and a normally closed contact and a common connection.
漂移: A gradual change in an element over time when the process conditions are constant.
干灯泡温度: The ambient air temperature measured by a thermometer that is freely exposed to the air but shielded from other heating or cooling effects.
Emissivity: The ratio of energy radiated by the material to energy radiated by a black body at the same temperature. It is a measure of a material’s ability to absorb and radiate energy.
Gage Pressure (psig): The measure of force per area exerted by a fluid using atmospheric pressure as the zero reference.
热门交界处: The joined end of the thermocouple that is exposed to the process where the temperature measurement is desired.
湿度: The amount of water vapor in a given volume of air or gas.
Laminar Flow: Smooth fluid flow that has a parabolic flow profile with no mixing between streamlines.
线性: Ability of a measuring instrument to provide an indication having a linear relationship with a defined quantity other than an influence quantity. [IEC 60050-300]
注意: The method of expression of lack of linearity is different for different kinds of instruments and is established in each particular instance.
Long-Term Span Drift: The amount of change of a measured reading with 90% of full scale range pressure applied and constant ambient conditions over a given period of time which is typically quoted as an annual figure. [IEC 61298-2]
Long-Term Zero Drift：测量读数的变化量，零压力施加零压力和恒定的环境条件，在给定的时间段内通常引用为年度数字。
Low Pressure Steam: As defined by ASME, steam under 15 psi pressure.
Maximum Surge Pressure：开关外壳的安全压力，但这可能通过连续或重复应用损坏机制。
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.
发射机: A device that translates the low-level output of a sensor or transducer to a higher level signal suitable for transmission to a site where it can be further processed.
Turbulent Flow: Fluid flow in which the flow profile is a flattened parabola, the streamlines are not present, and the fluid is freely mixing.
调低比: The ratio of the maximum to minimum measurable value that can still produce full-scale output.
Velocity Pressure (Dynamic Pressure): The pressure exerted by the velocity of a fluid. Can be measured by the difference between total and static pressure.