Knowledge
Metrology Dictionary
The complete VIM vocabulary — all numbered concepts of JCGM 200:2012 as faithful paraphrases with clause citations — plus clearly labeled practice terms from the GUM, ILAC, ISO and NIST guidance.
Scale of a displaying measuring instrument
The part of a displaying instrument consisting of an ordered set of marks with associated quantity values.
VIM (JCGM 200:2012) 3.5 · Instruments
Secondary measurement standard
A standard established through calibration with respect to a primary standard for a quantity of the same kind.
VIM (JCGM 200:2012) 5.5 · Standards & Units
Selectivity of a measuring system
The property whereby the system provides measured values for one or more measurands that are independent of other measurands or influence quantities.
VIM (JCGM 200:2012) 4.13 · Instruments
Sensitivity coefficient
The partial derivative ∂f/∂xᵢ of the measurement model with respect to an input quantity, evaluated at the estimates: it converts an input standard uncertainty into its contribution to the uncertainty of the result.
GUM (JCGM 100:2008) 5.1.3 · Uncertainty
Sensitivity of a measuring system
The quotient of the change in an indication and the corresponding change in the value of the quantity being measured.
VIM (JCGM 200:2012) 4.12 · Instruments
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 · Instruments
Stability of a measuring instrument
The property of an instrument whereby its metrological properties remain constant in time — quantified by the time taken to drift a stated amount, or the change over a stated time.
VIM (JCGM 200:2012) 4.19 · Instruments
Standard measurement uncertainty
Measurement uncertainty expressed as a standard deviation, denoted u — the common currency into which all components are converted before combination.
VIM (JCGM 200:2012) 2.30 · Uncertainty
Standard platinum resistance thermometer (SPRT)
The interpolation instrument of the ITS-90 between defined fixed points over most of its range: a strain-free platinum resistor whose resistance ratio W(T) maps to temperature.
ITS-90 · Temperature
Standard reference data
Reference data issued by a recognized authority — the CODATA constants and NIST standard reference databases are the working examples.
VIM (JCGM 200:2012) 5.17 · Standards & Units
Steady-state operating condition
An operating condition under which the relation established by calibration remains valid even though the measurand varies with time.
VIM (JCGM 200:2012) 4.8 · Instruments
Step response time
The duration between the instant an input quantity is subjected to an abrupt change between two specified constant values and the instant the indication settles within specified limits of its final steady value.
VIM (JCGM 200:2012) 4.23 · Instruments
Submultiple of a unit
A unit obtained by dividing a given unit by an integer greater than one — the millimetre from the metre.
VIM (JCGM 200:2012) 1.18 · Standards & Units
System of quantities
A set of quantities together with the non-contradictory equations relating them — the framework a system of units is built on.
VIM (JCGM 200:2012) 1.3 · Standards & Units
System of units
A set of base and derived units, with their multiples and submultiples, defined under given rules for a given system of quantities.
VIM (JCGM 200:2012) 1.13 · Standards & Units
Systematic measurement error
The component of measurement error that in replicate measurements remains constant or varies predictably. Known systematic errors are compensated by correction.
VIM (JCGM 200:2012) 2.17 · General