Technical data

Diagnostics
23.6 Diagnosing in STOP Mode
Programming with STEP 7
492 Manual, 05/2010, A5E02789666-01
23.6 Diagnosing in STOP Mode
23.6.1 Basic Procedure for Determining the Cause of a STOP
To determine why the CPU has gone into "STOP" mode, proceed as follows:
1. Select the CPU that has gone into STOP.
2. Select the menu command PLC > Diagnostics/Settings > Module Information.
3. Select the "Diagnostic Buffer" tab.
4. You can determine the cause of the STOP from the last entries in the diagnostic buffer.
If a programming error occurs:
1. The entry "STOP because programming error OB not loaded" means, for example, that the
CPU has detected a program error and then attempted to start the (non-existent) OB to handle
the programming error. The previous entry points to the actual programming error.
2. Select the message relating to the programming error.
3. Click the "Open Block" button.
4. Select the "Stacks" tab.