Dictionary · Instruments
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.
Related terms
More from Instruments
Dead band
The maximum interval through which the value of the quantity being measured can be changed in both directions without producing a detectable change in indication — hysteresis's operational signature.
VIM (JCGM 200:2012) 4.17
Indication
The quantity value provided by a measuring instrument or system — the reading, before any correction.
VIM (JCGM 200:2012) 4.1
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.
VIM (JCGM 200:2012) 4.21
Datum measurement error
The measurement error of an instrument or system at a specified measured value — the error quoted at a named point rather than over the whole interval.
VIM (JCGM 200:2012) 4.27
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
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