Siemens CPU 410-5H Process Automation System Manual page 107

For detailed information on SFC 90 "H_CTRL", refer to Manual
300/400, System and Standard Functions
Note
In a fail-safe system, you are not allowed to disable and then re-enable the cyclic self-tests.
For more details, refer to Manual
CPU 410-5H Process Automation/CPU 410 SMART
System Manual, 10/2013, A5E32631667-AA
Operator controls and operating modes of the CPU 410-5H
.
S7-400F and S7-400FH Automation Systems
7.3 Self-test
System Software for S7-
.
107