D-59Height Gage Performance Evaluation MethodJIS B 7517 was revised and issued in 2018 as the Japanese Industrial Standards of the height gage, and the “Instrumental error” indicating the indication error of the height gage has been changed to “Maximum permissible error (MPE) of indication”. The “Instrumental error” of the conventional JIS adopts acceptance criteria that the specication range (precision specication) equals acceptance range, and the OK/NG judgment does not include measurement uncertainty (Fig. 1).The “Maximum permissible error (MPE) of indication” of the new JIS employs the basic concept of the OK/NG judgment taking into account the uncertainty adopted in the ISO standard (ISO 14253-1).The verication of conformity and nonconformity to the specications is clearly stipulated to use the internationally recognized acceptance criteria (simple acceptance) when the specication range equals the acceptance range, and it is accepted that the specication range equals the acceptance range if a given condition considering uncertainty is met.The above said internationally recognized acceptance criterion is ISO/TR 14253-6: 2012 (Fig. 2).The following describes the standard inspection method including the revised content of JIS 2018.JIS B 7517-1993 JIS B 7517: 2018 (ISO/TR 14253-6: 2012)UUUUFig. 1Conventional JIS Instrumental errorSpecication rangeNon-conformity rangeConformity rangeNon-conformity rangeAcceptance rangeFig. 2New JIS Maximum permissible error (MPE)Specication rangeConformity rangeNon-conformity rangeAcceptanceNon-conformity rangeUncertaintyrangeUncertaintyrangeUncertainty is not included in judgmentSpecication range=Acceptance rangeWhen a condition considering uncertainty is satisedSpecication range=Conformity range(Rejected)(Rejected)Maximum permissible error of height measurement EMPE [JIS B 7517: 2018]The height measurement error in a height gage is the indication error when the reference edge (column) is perpendicular to the base reference surface and the direction of contact is downward. Table 1 shows the maximum permissible height measurement error EMPE. EMPE for any desired height is obtained by measuring a gauge block, or equivalent, with a height gage on a precision surface plate (Fig. 3) and then subtracting the gauge block size from the measured size.Unit: mmMeasurement heightScale interval, graduation or resolution0.050.02 or 0.0150 or less±0.05±0.02Over 50, 100 or less±0.06±0.03Over 100, 200 or less±0.07Over 200, 300 or less±0.08±0.04Over 300, 400 or less±0.09Over 400, 500 or less±0.10±0.05Over 500, 600 or less±0.11Over 600, 700 or less±0.12±0.06Over 700, 800 or less±0.13Over 800, 900 or less±0.14±0.07Over 900, 1000 or less±0.15Note: EMPE includes the measurement error arising from straightness, flatness of the measuring surface and parallelism with the reference surface.The “Instrumental error” indicating the indication error of JIS has been changed to “Maximum permissible error (MPE) of indication” for the following models:• SERIES 192 Digimatic Height Gage described on page D-43 (All models)• SERIES 570 ABSOLUTE Digimatic Height Gage described on page D-45 (All models)• SERIES 570 Digimatic Height Gage described on page D-47 (All models)• SERIES 514, 506 Standard Height Gage with Adjustable Main Scale described on page D-49 (All models)• SERIES 192 With digital counter described on page D-50 (All models)Fig. 3: Determination of height measurement errorGauge blockPrecision surface plateHeight gageTable 1: Maximum permissible height measurement error EMPE of a conventional height gageD

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