Technical data

Diagnostics
23.9 Program Measures for Handling Errors
Programming with STEP 7
Manual, 05/2010, A5E02789666-01 503
23.9.2 Error OBs as a Reaction to Detected Errors
Detectable Errors
The system program can detect the following errors:
• CPU functioning incorrectly
• Error in the system program execution
• Errors in the user program
• Error in the I/Os
Depending on the type of error, the CPU is set to STOP mode or an error OB is called.
Programming Reactions
You can design programs to react to the various types of errors and to determine the way in which
the CPU reacts. The program for a particular error can then be saved in an error OB. If the error
OB is called, the program is executed.