Patent ID: 7130171
Filing Date: 2006-10-31
Classification: G05B,H01H

Abstract:
1. In an industrial production plant having a plurality of electrical loads, an apparatus for fail-safely disconnecting at least one of the electrical loads in order to prevent hazards originating from the production plant, the apparatus having: a first and at least one second safety switching device each operatively connected to at least one of the electrical loads, with the first safety switching device comprising a first evaluation and control unit, an output and an electronic switching element for producing a potential-related switching signal at the output under the control of the first evaluation and control unit, the potential-related switching signal activating or de-activating at least one of the electrical loads, with the second safety switching device comprising an input and a second evaluation and control unit operatively connected to the input for receiving the potential-related switching signal, wherein the output and the input are connected to one another via a single-channel connecting line, and wherein the second safety switching device comprises at least two input stages to which the potential-related switching signal is supplied redundantly with respect to one another, the two input stages each monitoring the potential-related switching signal redundantly with respect to one another.