| 主权项 |
1. A safety switching apparatus for switching on or off a technical installation in a failsafe manner, comprising
a failsafe control/evaluation unit having an input for receiving an input signal representative of the technical installation and having a first output for providing an output signal as a function of the input signal, an electromechanical switch having an operating contact for connecting or disconnecting a load current to the technical installation, and having an auxiliary contact mechanically coupled with the operating contact in order to establish an auxiliary contact current path which is electrically isolated from the operating contact, and a switching element arranged in the auxiliary contact current path, wherein the first output is coupled to the electromechanical switch for driving the operating contact in response to the output signal at a defined output signal time, wherein the failsafe control/evaluation unit is designed for checking the switching position of the operating contact by monitoring the auxiliary contact current path, wherein the failsafe control/evaluation unit is further designed to produce a switching signal at a defined switching signal time which is different from the output signal time, and wherein the switching element is driven in response to the switching signal in order to selectively allow or interrupt an auxiliary current flow in the auxiliary contact current path. |
