SAFETY SWITCHING DEVICE FOR DETECTING FAULTY INPUTS

摘要

A fail-safe safety switching device comprises first and second input channels for receiving first and second input signals, and a first testing arrangement for testing the first and second input channels. The first input channel comprises a first entry circuit and a first threshold element connected via a first coupling element to a second testing arrangement and a first transition circuit in a galvanically isolated manner. The second input channel comprises a second entry circuit and a second threshold element connected via a second coupling element to a third testing arrangement and a second transition circuit in a galvanically isolated manner. The first testing arrangement comprises a third coupling element, a ground terminal and a group testing terminal. The first and second threshold elements are connected to the ground terminal and via the third coupling element to the group testing terminal in a galvanically isolated manner.