Glossary

Conversion Tables

Hazardous Location Classification

Pressure Transducer Installation and Use

Waterhammer

GLOSSARY

Watt Density: The watts emanating from each square inch of heated surface area of a heater. Expressed in units of watts per square inch.

Wheatstone Bridge: A network of four resistances, an emf source, and a galvanometer connected such that when the four resistances are matched, the galvanometer will show a zero deflection or "null" reading.

Window: In computer graphics, a defined area in a system not bounded by any limits; unlimited "space" in graphics.

Word: Number of bits treated as a single unit by the CPU. In an 8-bit machine, the word length is 8 bits; in a sixteen bit machine, it is 16 bits.

Working Standard: A standard of unit measurement calibrated from either a primary or secondary standard which is used to calibrate other devices or make comparison measurements.

Write: To record data in a storage device or on a data medium.

Young's Modulus: Young's Modulus (the Modulus of Elasticity) is equivalent to the ratio of normal stress to strain.

Zero Adjustment: The ability to adjust the display of a process or strain meter so that zero on the display corresponds to a non-zero signal, such as 4 mA, 10 mA, or 1 V dc. The adjustment range is normally expressed in counts.

Zero Offset: 1. The difference expressed in degrees between true zero and an indication given by a measuring instrument. 2. See Zero Suppression

Zero Point: The electrical zero point where zero millivolts would be displayed. Used in conjunction with the slope control to provide a narrower range calibration.

Zero Power Resistance: The resistance of a thermistor or RTD element with no power being dissipated.

Zero Suppression: The span of an indicator or chart recorder may be offset from zero (zero suppressed) such that neither limit of the span will be zero. For example, a temperature recorder which records a 100° span from 400° to 500° is said to have 400° zero suppression.

Zero Voltage Switching: The making or breaking of circuit timed such that the transition occurs when the voltage wave form crosses zero voltage; typically only found in solid state switching devices.

Zooming: In computer graphics, causing an object to appear smaller or larger by moving the window and specifying various window sizes.