Technical data

Appendix
27.2 Memory Areas of S7 CPUs
Programming with STEP 7
584 Manual, 05/2010, A5E02789666-01
Diagnostic Buffer Content
The upper list box contains a list of all the diagnostic events that occurred with the following
information:
• Serial number of the entry (the newest entry has the number 1)
• Time and date of the diagnostic event: The time and date of the module are displayed if the
module has an integrated clock. For the time data in the buffer to be valid, it is important that
you set the time and date on the module and check it regularly.
• Short description of the diagnostic event
In the lower text box, all the additional information is displayed for the event selected in the list in
the upper window. This information includes:
• Event number
• Description of the event
• Mode transition caused by the diagnostic event
• Reference to the location of the error in a block (block type, block number, relative address)
which caused the entry in the buffer
• Event state being entered or left
• Additional information specific to the event
With the "Help on Event" button you can display additional information on the event selected in the
upper list box.
Information on event IDs can be found in the Reference Help on System Blocks and System
Functions (Jumps to Language Descriptions and Help on Blocks, System Attributes)
Saving the Contents in a Text File
Using the "Save As" button in the "Diagnostic Buffer" tab of the "Module Information" dialog box
you can save the contents of the diagnostic buffer as ASCII text.
Displaying the Diagnostic Buffer
You can display the contents of the diagnostic buffer on the programming device via the
"Diagnostic Buffer" tab in the "Module Information" dialog box or in a program using the system
function SFC51 RDSYSST.
Last Entry before STOP
You can specify that the last diagnostic buffer entry before the transition from RUN to STOP is
automatically sent to a logged on monitoring device (for example, PG, OP, TD) in order to locate
and remedy the cause of the change to STOP more quickly.