Dictionary · Instruments
Measuring system
One or more measuring instruments and often other devices, assembled and adapted to give measured values within specified intervals for quantities of specified kinds.
Related terms
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Null measurement uncertainty
The measurement uncertainty when the specified measured value is zero — what limits how confidently a null or tare reading can be trusted.
VIM (JCGM 200:2012) 4.29
Rated operating condition
An operating condition that must be fulfilled during measurement for an instrument to perform as designed — the environmental and use envelope the specs assume.
VIM (JCGM 200:2012) 4.9
Sensor
The element of a measuring system directly affected by the phenomenon, body, or substance carrying the quantity being measured — the Pt resistance element in an SPRT, the seismic mass in an accelerometer.
VIM (JCGM 200:2012) 3.8
Resolution
The smallest change in the quantity being measured that causes a perceptible change in the corresponding indication. Digital resolution contributes a rectangular uncertainty component of (δ/2)/√3.
VIM (JCGM 200:2012) 4.14
Accuracy class
A class of instruments or systems that meet stated metrological requirements intended to keep errors or instrumental uncertainties within specified limits under specified conditions — OIML weight classes E1 through M3 are the canonical example.
VIM (JCGM 200:2012) 4.25
Maximum permissible error (MPE)
The extreme value of measurement error, with respect to a known reference value, permitted by specifications or regulations for a given instrument. Verification confirms indications fall within ±MPE.
VIM (JCGM 200:2012) 4.26