DC voltage network circuit for reading input signals for switching units with external DC supplies, esp. programmable small controllers

摘要

The circuit uses the external voltage supply as the voltage supply for the connection of the signal inputs and has a supply voltage buffer (20). There is an arrangement (22) for detecting the non-buffered power supply and for generating an additional signal depending on the presence of the detected supply voltage, whereby the signal inputs are read by the computer unit depending on the state of the generated signals An Independent claim is also included for a method of reading input signals for switching units with external DC supplies, esp. programmable small controllers.