What does a gauge accuracy statement really mean?
Accuracy is the conformity of a gauge indication to an accepted standard or true value. Accuracy is the difference between the true value and the gauge indication expressed as a percent of the gauge span. It is the combined effects of method, observer, apparatus, and environment. Accuracy error includes hysteresis and repeatability errors. An ASME B40.1 class B gauge has three accuracies. A 3-2-3 percent of span designation stands for 3% in the first quarter of the scale, 2% in the middle half of the scale and 3% in the upper quarter of the scale.
