systems and methods for an industrial i / o controller circuit for frequency input modules that measure the frequency of an electrical input signal using adaptive threshold voltage and / or adaptive hysteresis feedback are shown and described . the systems and methods provide advantages in that the i / o controller circuit can better distinguish between actual input pulses from the electrical input signal , as opposed to unwanted electromagnetic interference induced input pulses . this maximizes the amount of emi rejection , independent of the frequency of the moving machine , and results in less time to commission and adjust a sensor , fewer false frequency measurements and less system down time .