Patent ID: 7705492
Filing Date: 2010-04-27
Classification: G01D,G01R,H01H

Abstract:
1. A safety switching device for failsafe shutdown of an electrical load, comprising: at least one input terminal for receiving a status signal representing a safety request, an evaluation and control unit for evaluating the status signal, at least one switching element controlled by the evaluation and control unit in response to the status signal, and at least one position encoder for setting an operational quantity, the at least one position encoder comprising a first terminal, a second terminal, and a tap having a variable instantaneous position, with a total impedance being defined between the first terminal and the second terminal, with a first partial impedance being defined between the first terminal and the tap, and with a second partial impedance being defined between the tap and the second terminal, wherein the evaluation and control unit is configured to determine a first measurement value representative of the first partial impedance and to determine a second measurement value representative of the second partial impedance in order to determine the instantaneous position of the tap in a failsafe manner.