The most common and well known application of synchronous counters is machine motion control, the process in which the rotary shaft encoders convert the mechanical pulses into electric pulses. These pulses will act as clock input of the up/ down counter and will initiate the circuit motion.
This circuit consists of photo transistor or light sensor and a LED connected to the rotor shaft. This arrangement is connected to the UP/ DOWN counter. When the machine started to move, it turns the encoder shaft by connecting and disturbing (making and breaking) the light beam between the light sensor and LED.
By this motion, the rotor creates clock pulses to increase the count of the up/ down counter circuit. So the counter note downs the motion of the shaft and gives the value that how much distance the rotor has moved.
To count the motion of the rotor shaft we increment the count by moving shaft in one direction and decrement the count by moving in another direction. We also use an encoder /decoder circuit to differentiate the direction of motion.
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