GlossaryConversion TablesHazardous Location ClassificationPressure Transducer Installation and UseWaterhammer |
GLOSSARYJoule: The basic unit of thermal energy. Journal: A journal is that part of a rotor that is in contact with or supported by a bearing in which it revolves. Junction: The point in a thermocouple where the two dissimilar metals are joined. K: When referring to memory capacity, two to the tenth power (1024 in decimal notation). Kelvin: Symbol K. The unit of absolute or thermodynamic temperature scale based upon the Celsius scale with 100 units between the ice point and boiling point of water. 0°C = 273.15K (there is no degree (°) symbol used with the Kelvin scale). Kilowatt (kw): Equivalent to 1000 watts. Kilowatt Hour (kwh): 1000 watthours. Kilovolt amperes (kva): 1000 volt amps. Kinetic Energy: Energy associated with mass in motion, i.e., 1/2 rV2 where r is the density of the moving mass and V is its velocity. KVA: Kilovolt amperes (1000-volt amps). Lag: 1. A time delay between the output of a signal and the response of the instrument to which the signal is sent. 2. A time relationship between two waveforms where a fixed reference point on one wave occurs after the same point of the reference wave. Laminar Flow: Streamlined flow of a fluid where viscous forces are more significant than inertial forces, generally below a Reynolds number of 2000. Large Scale Integration (LSI): The combining of about 1,000 to 10,000 circuits on a single chip. Typical examples of LSI circuits are memory chips and microprocessor. Latent Heat: Expressed in BTU per pound. The amount of heat needed (absorbed) to convert a pound of boiling water to a pound of steam. Leakage Rate: The maximum rate at which a fluid is permitted or determined to leak through a seal. The type of fluid, the differential Limits of Error: A tolerance band for the thermal electric response of thermocouple wire expressed in degrees or percentage defined by ANSI specification MC-96.1 (1975). Least-squares Line: The straight line for which the sum of the squares of the residuals (deviations) is minimized. Life Cycle: The minimum number of pressure cycles the transducer can endure and still remain within a specified tolerance. Limits of Error: A tolerance band for the thermal electric response of thermocouple wire expressed in degrees or percentage defined by ANSI specification MC-96.1 (1975). Linearity: The closeness of a calibration curve to a specified straight line. Linearity is expressed as the maximum deviation of any calibration point on a specified straight line during any one calibration cycle. Liquid Junction Potential: The potential difference existing between a liquid-liquid boundary. The sign and size of this potential depends on the composition of the liquids and the type of junction used. Load Impedance: The impedance presented to the output terminals of a transducer by the associated external circuitry. Load: The electrical demand of a process expressed as power (watts), current (amps) or resistance (ohms). Logarithmic Scale: A method of displaying data (in powers of ten) to yield maximum range while keeping resolution at the low end of the scale. Loop Resistance: The total resistance of a thermocouple circuit caused by the resistance of the thermocouple wire. Usually used in reference to analog pyrometers which have typical loop resistance requirements of 10 ohms. LS-TTL Compatible: For digital input circuits, a logic 1 is obtained for inputs of 2.0 to 5.5 V which can source 20 ╡A, and a logic 0 is obtained for inputs of 0 to 0.8 V which can sink 400 ╡A. For digital output signals, a logic 1 is represented by 2.4 to 5.5 V with a current source capability of at least 400 ╡A; and a logic 0 is represented by 0 to 0.6 V with a current sink capability of at least 16 MA. "LS" stands for low-power Schottky. LS-TTL Unit Load: A load with LS-TTL voltage levels, which will draw 20 ╡A for a logic 1 and -400 ╡A for a logic 0. LSD (Least-Significant Digit): The rightmost active (non-dummy) digit of the display. |