ASME MFC-1-2014 pdf free download.Glossary of Terms Used in the Measurement of Fluid Flow in Pipes
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(1) A general form of a measurement model is the equation h(Y, (X 1 …,X n ) p 0, where Y, the output quantityin the measurement model, is the measurand, the quantity value of which is to be inferred from information about input quantities in the measurement model X 1 …,X n .
(2) In more complex cases where there are two or more output quantities in a measurement model, the measurement model consists of more than one equation. measurement precision: closeness of agreement between indications or measured quantity values obtained by replicate measurements on the same or similar objects under specified conditions.
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(1) Measurement precision is usually expressed numerically by measures of imprecision, such as standard deviation, variance, or coefficient of variation under the specified conditions of measurement
. (2) The “specified conditions” can be, for example, repeatability conditions of measurement, intermediate precision conditions of measurement, or reproducibility conditions of measurement (see ISO 5725-3:1994).
(3) Measurement precision is used to define measurement repeat- ability, intermediate measurementprecision, and measurement reproducibility.
(4) Sometimes “measurement precision” is erroneously used to mean measurement accuracy. measurement procedure: set of operations, described in detail, used in the performance of particular measure- ments according to a given method, including any calcu- lation to obtain a measurement result.
NOTE: A measurement procedure should be documented in suf- ficient detail to enable an operator to perform a measurement and may include a statement concerning a target measurement uncertainty.
measurement repeatability: measurement precision under a set of repeatability conditions of measurement (set of conditions that includes the same measurement procedure, same operators, same measuring system, same operating conditions, and same location, and replicate measurements on the same or similarobjects over a short period of time).
measurement reproducibility: measurement precision under reproducibility conditions of measurement (a set ofconditions that includes differentlocations, operators, measuring systems, and replicate measurements on the same or similar objects).
measurement result: set of quantity values being attrib- uted to a measurand, together with any other relevant information.
NOTES: (1) A measurement result is generally expressed as a single mea- sured quantity value and its uncertainty. If the measurement uncertaintyis considered to be negligible fora specific purpose,the measurement result may be expressed as a single measured quantity value.
(2) A measurement result may contain “relevant information” about the set of quantity values, such that some may be more representative of the measurand than others. This may be expressed in the form of a probability density function. measurement section: length of conduit between two mea- surement cross sections, two sampling cross sections, or between an injection and a sampling cross section. For ultrasonic flowmeters:
The section of conduit in which the volumetric flow rate is sensed by the acoustic signals and is bounded at both ends by planes perpendicular to the axis of the section and located at the extreme upstream and downstream transducer positions. measurement sensor, coriolis: sensor to detect the Coriolis effect and to measure the frequency of the tube oscillations. measurement standard: realization of the definition of a given quantity, with stated quantity value and associ- ated measurement uncertainty, used as a reference, e.g., 1 kg mass measurement standard with an associated standard measurement uncertainty band of 3g; or a 100 measurement standard resistor with an associated standard measurement uncertainty of 1 .
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(1) A “measurement standard” can be provided by a measuring system, a material measure, or a reference material.
(2) A measurement standard is frequently used as a reference in establishing measured quantity values and associated mea- surement uncertainties for other quantities of the same kind, thereby establishing metrological traceability through calibra- tion of other measurement standards, measuring instruments, or measuring systems
. (3) The term “realization” used denotes three procedures of “realization:”
(a) the physical realization of the measurement unit from its definition and is a realization in the strictest sense
(b) termed “reproduction”, consisting of setting up a highly reproducible measurement standard based on a physical phe nomenon, as it happens
(c) consisting in adopting a material measure as a measure- ment standard, e.g., the measurement standard of 1 kg.ASME MFC-1 pdf download.ASME MFC-1-2014 pdf free download
