Circuito de entrada seguro con terminal de periféricos monocanal para la entrada de un abonado de bus

摘要

The circuit has a signal input circuit (110) with a single channeled peripheral port (INO) for connecting a signal encoder, an evaluating circuit (120) and a comparator circuit (200). The evaluating circuit is electrically connected with the peripheral port by a coupling unit (IC1). The comparator circuit is electrically connected with the peripheral port for adjusting a reference voltage to activate and deactivate the coupling unit. The comparator circuit comprises a reference voltage source and a testing circuit for testing the reference voltage source.