Monitoring reading measurement
The JJG117-91 flat plate verification procedure stipulates that when the flatness is used to verify the flatness, the bridge plate with the level is fixed on the tested flat plate, and the bridge plate is grounded first and last according to a certain layout point, and the measured plane is measured. The inclination angle of the adjacent mesh point is measured relative to the measurement base surface (natural horizontal plane), and the flatness error value is obtained by data processing. For flat panel inspection, the position of the natural water level must be ensured throughout the measurement.