Dictionary · Instruments
Instrumental drift
A continuous or incremental change of an indication over time, due neither to a change in the quantity being measured nor to a recognized influence quantity — a key input to calibration-interval decisions.
Related terms
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Indication interval
The set of quantity values bounded by the extreme possible indications.
VIM (JCGM 200:2012) 4.3
Nominal quantity value
A rounded or approximate value of a characterizing quantity of a measuring instrument that guides its appropriate use — the "100 Ω" stamped on a resistor, the "1 kg" of a weight.
VIM (JCGM 200:2012) 4.6
Variation due to an influence quantity
The difference in indication, or in the supplied quantity value of a material measure, when an influence quantity assumes two different specified values — the temperature coefficient on a datasheet is one of these.
VIM (JCGM 200:2012) 4.22
Measuring instrument
A device used for making measurements, alone or in conjunction with supplementary devices.
VIM (JCGM 200:2012) 3.1
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
Detection limit
The measured value, obtained by a given procedure, for which the probability of falsely claiming absence of a component is β, given a probability α of falsely claiming its presence — the statistically honest "smallest amount we can claim to see".
VIM (JCGM 200:2012) 4.18