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There are a lot of definitions and terms relating to measurement and measurement devices. This is our best shot at trying
to standardize terminology. Even though we may have a completely accurate definition here, always confirm the meanings with the supplier of your measuring equipment or service.
Absolute Position (ABS):Typically used on electronic measuring instruments. May also be referred to as the origin. It is
the base reference position for the instrument and may be set at any location within the measuring range. It is typically set
at the lowest reading position during calibration and remains there until reset or battery change.
Zero Set Point: Typically used on measuring instruments when an offset amount from some standard reference value is
desired rather than the distance from the Absolute Position is desired.
Graduation: The smallest unit of measurment that is defined on the measuring device.
Resolution: The smallest unit that the person measuring can be expected to discriminate from the graduations. On a line
type device, this is typically 1/2 of the graduated readings. On an electronic device it is typically the same as the resolution.
Accuracy:The difference between the average of repeated readings of a precisely known standard and the known value of the standard.
Bias: The difference between the observed average of measurements and the master average of the same parts using precision instruments.
Linearity: Difference in the bias values of a gage through the expected operating range of the gage.
Repeatability: Variation in measurements obtained with one gage when used several times by one persone while
measuring a characteristic on one part.
Reproducibility: Variation in the average of the measurements made by different people using the same gage when
measuring a characteristic on one part.
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