F_Testm - Siemens SIMATIC S7 F Manual

Fail-Safe Blocks
8.6.12

F_TESTM

Function
This block is for activating/deactivating safety mode.
At compilation, the block is inserted automatically into a F-run-time group named
@F_TestMode.
I/Os
The block has no visible I/Os.
Error Handling
None
Operation and Monitoring
The invisible TEST parameter has the system attribute S7_m_c. It can therefore be
monitored directly from an operator interface system (OS). You can thus see on
your display whether safety mode is active or inactive.
•
0: Safety mode active
•
1: Safety mode inactive
Report Characteristics
When safety mode is activated/deactivated, the block issues the message "PLC
not in safety mode" to the OS using SFB 33 (ALARM).
The messages can be switched off via the (invisible) input EN_MSG = 0
(MSG_STAT output parameter remains unchanged) if a suitable report system is
not available.
The ALARM block is called if message suppression is not activated. ALARM error
information (messages cannot be issued) is displayed in the (invisible) MSG_STAT
output parameter.
Error information of the MSG_STAT output parameter is described in detail in the
online help system for SFB 33 (ALARM).
General message text: Safety program is not in safety mode
Message class: process message with acknowledgment
Fail-Safe Systems
A5E00085588-03
8-79