Processing Method of Optical Grating Scale Output Signal

When designing the water level measuring instrument, incremental optical grating scale is used as position sensor. Since the water level must be measured repeatedly and continuously, cumulative error of measuring is the critical issue. Using asynchronous sequential logic circuit-level design approach, abstracting signal timing diagram from various moments of changing direction, designing of incentive state and output function expression and writing the expression to a programmable device, a grating scale processing circuit can be constructed. The water level measuring instrument based on this circuit is running perfectly on the model of Yangtze River flood proofing, indicating no cumulative errors are produced. The device can also be used for optical encoder position measurement and other measurements.