Patent ID: 9739822
Date: 2017-08-22
CPC Classifications: G01R

Claim:
1. An input circuit which has a plurality of input terminals connected to a plurality of input lines transmitting an input signal outputted from a plurality of input signal sources, the input circuit comprising: a controller which outputs a control signal when performing self-diagnosis of a short-circuit fault between the input lines; a pulse circuit which generates pulsed self-diagnosis voltage once, twice or more times based on the control signal of the controller; a switch which, when performing the self-diagnosis, applies the pulsed self-diagnosis voltage to only one of the input lines based on the control signal of the controller; and a comparing/determining circuit which, when the self-diagnosis voltage is applied to the only one of the input lines, determines whether the short-circuit fault between the input lines has occurred based on voltage variation in the input line different from the input line to which the self-diagnosis voltage is applied.