Input circuit of the on or off type for a programmable automatic device.

摘要

An on or off input circuit (10) enables detection of the state of a sensor (12) to which it is connected, and the defects in the input system by comparing the input voltage (Ve) with driven thresholds, with the supply voltage (Va). In a microprocessor input circuit (24) this can be achieved by comparing with fixed digital thresholds of the input voltage (Ve) converted into digital by means of an analog-digital converter (28) whose reference voltage (Vref) is driven at the supply voltage. <IMAGE>