Digital gauge is a metrological tool which uses the rack gear or the level gear operation to transfer the line displacement of the survey rod into an angular one of the pointer hand. Its main usage is to measure the size、the shape and the position error of products.
Digital gauges with in 0.01 mm readings can be calibrated by use of a raster calibration instrument for digital gauges or a alibrator for digital gauges with 0.01mm readings. Digital gauges with 0.001 mm readings can be calibrated by use of a raster calibration instrument or digital gauges or a calibrator digital gauges with 0.001 mm readings. Other methods can be used for the calibration, the accuracy of which should not be lower.
During the whole calibration process the direction of travel of the survey rod must not be changed right in the middle and any adjustment must not be done on the calibrated digital gauge and on the calibrating instrument (or the calibrator). Whether the error in the return ravels positive or negative can be determined in the same way as that for the forward travel running distance.
