Reading Diagnostic And Message Information From The Safety Program - Siemens SIMATIC S7-1200 Safety Programming Manualline

3 Methods for Safety Programming
Advantages

Lean F-runtime group

Better overview of the exchanged data

Changes of the diagnostic and signaling concept in the standard user
program do not affect the safety program's signature

Minimized risk of downtimes caused by data corruption due to write access
to the safety program

Simplified typing of F-blocks

Changes to the standard user program can be loaded without stopping the
CPU

Standard user program and safety program can be created independently
of each other, provided that interfaces have already been defined
3.9.1

Reading diagnostic and message information from the safety program

A frequent application for data exchange between the standard user program and
the safety program is the visualization of diagnostic and message information such
as:

Acknowledgment requests of errors

Reset requests of safety functions

Error messages

States of safety functions
Transfer the "raw data" from the safety program. The logic operation then takes
place in the standard user program. This has the advantage that the safety
program is kept lean and is independent of changes in the standard user program.
Smaller changes at a later stage (e.g., changes to the control of an indicator light)
are made in the standard user program. This does not change accepted F-blocks.
If you transfer a large amount of diagnostic data from the safety program, create an
F-data type for this purpose. A tag with a self-defined data type keeps the block
interface compact and clear. For data always to be transferred in a similar way, it is
recommended to standardize these F-data types across all F-function blocks.
Figure 3-11: Reading diagnostic and message information from the safety program
Status
Safety Programming Guideline
Entry ID: 109750255, V1.0,
Standard user program
DataFromSafety
10/2017
Safety program
Sensors
29