Siemens PM-E F pm DC24V PROFIsafe Installation And Operating Manual page 85

Et 200s distributed i/o system - fail-safe modules

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Safety-Related Shutdown of Standard Output Modules

Refer to the Internet

(http://support.automation.siemens.com/WW/view/en/12461959/133300) for a list of all the

standard ET 200S modules.

Safety-related activation of standard DO module outputs is not possible. Only safety-related

shutdown is possible. The following issues must therefore be taken into consideration:

In the worst case you must consider all possible faults of the standard DO modules and the

programs controlling them for which the faults cannot be found directly. For example, the

PM-E F pp DC24V PROFIsafedoes not detect external short-circuits to L+ at the standard

DO module outputs.

All faults developing at the standard DO modules influence the process via final controlling

elements.

The process status must be made known to the F-CPU by way of sensors and a suitable

safety program.

The safety program must react in a safety-related and logically suitable fashion to

unwanted or potentially dangerous states in the process via the PM-E F pp DC24V

PROFIsafe and fail-safe output modules.

If you want to avoid the problems described above completely, we recommend that you use

P/M switching fail-safe electronic modules 4 F-DO DC24V/2A PROFIsafe with standard

ET 200S power modules instead of standard DO modules.

Properties of safety-related shutdown of standard DO modules with the PM-E F pp DC24V

PROFIsafe:

This cost-effective solution allows the full and simultaneous shutdown of all outputs involved

when a fault is detected in the process or on the PM-E F pp DC24V PROFIsafe.

Property of the individual shutdown of F-modules with fail-safe outputs:

The scope of shutdown is kept to a minimum when a fault is detected. It is also possible to

react to critical process states staggered over time, or to perform safety-related shutdown of

individual outputs. Compared to the safety-related shutdown by the PM-E F pp DC24V

PROFIsafe, this solution costs more.

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