An anti-jamming counting approach for pulse signal of displacement sensor

This paper analyzes the variation of A-phase and B-phase pulse signals that displacement sensor outputs. A new anti-jamming counting approach is designed according to Gray code. This counting approach does not cause error count and counting precision is improved by four times frequency count. The principle of hardware and software is introduced in two application examples. In the first example, the input ports of AT89C52 MCU are connected to the outputs of hand rotary encoder. The MCU constantly checks the state of inputs in the timer interrupt and counts with this counting approach, then the count value is transfered to host computer through the RS422 interface. In the other example, the outputs of optical encoder are connected to the I/O ports of CPLD/FPGA chip which can count with this counting approach. Then the count value is transfered to host MCU/DSP through data lines. The applications resulted that the approach is good and the hardware circuit is simple, stable and reliable. The method has a certain practical value and can be applied to the anti-jamming counting for the other sensors which have the same output waveform.