Test GY910 Digital Coating Thickness Gauge Calibration stepClick CAL 4 times to enter NFE modeClick CAL 6 times to enter Fe modeWhen the display reads 0, put the probe on the plate. When the display reads 50, put 50 um film on the plate and click the POWER button to test. Repeat these steps for 100, 250, 500 and 1250. When the display reads AIR, switch the probe into AIR mode, then click the POWER button to calibrate - do not place the probe on the plate.