Siemens SIMATIC ET 200eco PN - Fail-safe shutdown of ET 200 eco PN standard modules; Back-up oriented shutdown of ET 200 eco PN standard modules

ET 200eco PN
261 Operating Instructions, 08/2016, A5E01250250-AJ
Fail-safe shutdown of ET 200eco PN standard
modules
G
G.1
Back-up oriented shutdown of ET 200eco PN standard modules
Introduction
The following structure describes how you can shutdown ET 200eco PN standard modules
in a fail-safe manner.
Through the displayed structure (with the safety shutdown device: for example, 3TK28), all
digital outputs that are connected to the supply 2L+ and 2M (24 V switched) from the ET
200eco PN standard modules are switched to the secure OFF state. Here the safety class
SIL2/Category 3/PLd is reached.
Principle of operation
The higher-level safety shutdown device (e.g. 3TK28) disconnects the supplies 2L+ and 2M
switched. The ET 200eco PN standard modules running on the supply 2L+ and 2M (24 V
switched) and their digital outputs are switched to the safe state. The digital outputs
connected to the supply 1L+ and 1M (24 V non-switched) are not intended for switching
under normal operating conditions and cannot be safely shutdown.
There is no opposite influence of the outputs.