Yokogawa digitalYEWFLO (DY) - Manual (Page 109)

IM 1F2B4-01-YIA
Page 104
GLOSSARY OF TERMS
CSA (Canadian Standards Association) - A testing agency located in Canada that reviews and tests
instruments to certify that they may be used safely in hazardous areas. See also FM.
Density - The mass of a substance per unit volume. Often expressed in terms of pounds per cubic foot.
Deviation - Parameter B28, where the “Z” factor is entered for gases which do not meet the
compressibility requirements necessary to be considered perfect or ideal gases. For Natural Gas per
the American Gas Association, Z=1/(F
pv
) 2 , where F
pv
is provided from the AGA Handbook.
EE PROM - Refers to internal circuit which maintains data settings permanently even without power.
Explosion-proof - Apparatus enclosed in a housing that is capable of withstanding an explosion of a
specified gas or vapor which may occur within it and of preventing the ignition of the specified gas or
vapor surrounding the enclosure, and which operates at such an external temperature that a
surrounding flammable atmosphere will not be ignited.
Flanged body style - A YEWFLO with flanges integral with the meter body, used to connect the meter
body to the pipeline. They are available in 150, 300 and 600 ANSI Class as required for the
application.
Flow conditioner - A device that is inserted in the pipeline upstream of a flowmeter for the purposes
of providing the proper flow profile necessary to obtain accurate measurement. It is only required
when there is not sufficient space to permit the normally required straight pipe ahead of the flowmeter.
Fluctuation - Parameter G20. When set to execute, this parameter traps the max or min flow rate and
stores these values in G21 and G22. To reset the values set G20 to not execute and then back to execute.
FM (Factory Mutual) - a company that reviews and tests instruments to assure that they will not
cause an explosion when properly used in a hazardous area.
Frequency - The number of repetitions of a periodic process in a unit of time. In the case of a vortex
meter, the frequency of the vertices being shed is proportional to the velocity of the flowing medium
within a pipeline.
Gain - The ratio of output change to input change at a specified frequency.
Hertz - A measure of the frequency in terms of cycles per second.
Integral converter - The YEWFLO electronics housing containing the amplifier circuit board when it
is attached directly to the flowmeter body.
Intrinsically safe - An instrument designed such that in the event of any electronic circuit failure there
will not be sufficient energy released that a spark could touch off an explosion. This in normally tested
and certified by FM, CSA, or other certifying agency.
K-factor - The number of pulses or vortices shed per unit volume. Normally expressed as pulses per
gallon.
Linear - Performance of a flowmeter so that if the points on the flow scale are plotted on a curve the
resulting curve will be a straight line. Does not require the use of a square root extractor. All
graduations on the flowmeter scale are equally spaced.