Technical data

Diagnostics
23.8 Flow of Diagnostic Information
Programming with STEP 7
496 Manual, 05/2010, A5E02789666-01
23.8.1 System Status List SSL
The system status list (SSL) describes the current status of the programmable logic controller. It
provides an overview of the configuration, the current parameter assignment, the current statuses
and sequences on the CPU, and the modules belonging to it.
You can only read the data in the system status list but not modify them. It is a virtual list that is
only created on request.
The information that you can display using the system status list can be divided into four areas.
Reading Out the System Status List
There are two ways of reading out the information in system status lists, as follows:
• Implicitly, via STEP 7 menu commands from the programming device (for example, memory
configuration, static CPU data, diagnostic buffer, status displays).
• Explicitly, via the system function SFC 51 RDSYSST in the user program, by entering the
number of the required partial system status list (see Help on Blocks )