VITAL DIGITAL INPUT

摘要

A digital input interface is provided which can be checked for its reliability. The configuration of the circuit on the input side allows a high impedance for a DC input signal and a low impedance for induced AC noise naturally attenuating any AC induced noise while maintaining the DC input signal. The interface also provides a latent failure detection engine. The latent failure detection engine can open and close an optocoupler on the input side of the interface which discharges and charges a capacitor on the input side. The time taken for the capacitor to recharge when the optocoupler is re opened is used to determine if there has been any threshold decay in the interface.