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Siemens AG
Entry type: Application example Entry ID: 109479280, Entry date: 12/16/2015

Emergency stop monitoring and protective door monitoring to SIL 3 or PL e with a 3SK2 safety relay

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Protective doors are frequently used to fence off danger zones. These are monitored for position and, if necessary, the area from which the hazard emanates is switched off. An emergency stop command device is additionally monitored for shutting down the machine in an emergency.


Operating principle
The safety relay monitors the two safety switches as well  as the emergency stop command device on two channels. When the emergency stop command device is actuated or the protective door is opened, the safety relay opens the enabling circuits and switches the power contactors off in a safety-related way.
If the door is closed, the emergency stop command device is unlatched and the feedback circuit is closed, the Start button can be used to switch on again.

 Registrierung notwendig  Project for Safety ES (2,0 KB)

 Registrierung notwendig  Wiring diagrams (163,8 KB)

 Registrierung notwendig  Project for Safety Evaluation Tool (17,8 KB)

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