Siemens Industry Online Support
Siemens AG
Entry type: FAQ Entry ID: 73137468, Entry date: 11/21/2017

SIRIUS Safety Integrated: Protective door monitoring with tumbler to SIL 2 or PL d with a Modular Safety System

  • Entry
  • Associated product(s)



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. If the machine continues to present a hazard even after switching off, access can be prevented for this period by a tumbler.


The position of a protective door is monitored via one safety switch. In addition, the door is locked via the safety switch. If the command to unlock the door is issued, the safety relay triggers and opens the enabling circuits, switching off the power contactors in a safety-related manner. The tumbler is unlocked after expiry of a set time. If the door is closed and locked, and the feedback circuit is closed, the Start button can be used to switch on again. 

The safety function "Protective door monitoring" and the safety function "Protective door tumbler" are designed for up to SIL 2 or PL d. 

Taking account of fault exclusions, use of only one safety switch with or without tumbler is permissible to SIL 2 or PL d. For further information, refer to the letter given below. 



Content of Downloads


Wiring diagrams   Wiring_Interlocking_MSS_SIL2.zip ( 65 KB )
Project for Modular Safety System ES
Interlocking_SIL2_sdp.zip ( 1 KB )
Project for Safety Evaluation Tool Interlocking_SIL2_MSS_set.zip ( 25 KB )
CAx download


Filter criteria: 

Hardware platform:  Safety, SIRIUS, MSS
Software:  MSS ES
Entry contens:  Application Examples