Patent ID: 6393053
Filing Date: 2002-05-21
Classification: G01R

Abstract:
A digital input unit including wire breakage detection, comprising:an input channel for receiving an input signal; a first voltage divider coupled to the input channel; a clock generator coupled to the voltage divider and generating a clock signal having a level which is less than a first threshold and greater than a second threshold, the input signal routed via the first voltage divider being superimposed on the clock signal; a logic circuit operating as a NOR gate and having a first input to which the input signal is supplied, and a second input to which the clock signal with the superimposed input signal is supplied; an electrical isolator; and an evaluation unit receiving a logic signal from the logic circuit via the isolator, the evaluation unit evaluating a direct voltage component of the logic signal and generating an output signal in a form of a status information logical â€œ0â€  or logical â€œ1â€  or a wire breakage output signal depending on the evaluation.