Activating Safety Mode - Siemens SIMATIC PCS 7 Operating Manual

Please note the following when deactivating safety mode
Manual intervention in the safety mode of fail-safe systems requires particular care and
attention.
● Any changes must be made in accordance with current change management guidelines.
● An influence analysis must be carried out on any changes to be made to the active
process.
● The changes must undergo a function test that complies with relevant standards (e.g. IEC
61511-1) before the program can be imported into the active plant.
As a general principle, the effect of changes on the system characteristics (program
runtime, etc.) must be analyzed. Following this, a final function test of all systems affected
by the changes (validation) must take place.
● The appropriate procedures for approval must be put in place before safety mode can be
deactivated.
Notification of the plant personnel in charge, deactivation of safety mode, change
downloading (delta downloading), and, finally, activation of safety mode must be
accompanied by the relevant documentation.
● This documentation will then include the results of the change comparison and its
analysis, the log of the relevant function test, and the updated hardware and software
documents, together with modified signatures.
While safety mode is deactivated, we highly recommend operating the plant with a high level
of supervision by the operating personnel. The measures required for this purpose are
derived from the influence analysis. This is urgently recommended due to the concluding
safety validation following a program change.
Safety mode should be reactivated as soon as the changes have been performed.
7.9.3

Activating safety mode

Following a download of changes, you will need to reactivate safety mode in order to ensure
secure execution of the the safety program.
Procedure
1. Select the CPU or its S7 program in the SIMATIC Manager.
2. Select the menu command "Options > Edit Safety Program".
3. Click the "Safety mode" button.
4. Confirm activation of the safety mode.
Note
If, when safety mode is deactivated, the safety program detects a safety-related error, it will
disable the option to activate safety mode. A corresponding message will appear indicating
how you can rectify the problem.
Compendium Part B - Process Safety (V8.2)
Operating Manual, 07/2016, A5E35031794-AB
Configuring the safety program
7.9 Safety mode and downloading the safety program
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