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Causes of Error and Reactions of the CPU
5.6.1
OB 19: Calling a Logic
Block That Is Not Loaded
(KB)
5.6.2
OB 19: Calling a Data Block
That Is Not Loaded (KDB)
5 - 24
If your program jumps to a block that does not exist, the system
program detects an error. This applies to all logic blocks and also for
conditional and unconditional calls.
When the system program detects the call of a logic block that is
not loaded, it calls OB 19, if this is loaded. In OB 19, you can
specify how the CPU should proceed.
If OB 19 does not exist, the system program continues executing the
interrupted STEP 5 program at the next operation.
If you call a data block or an extended data block in your program that
does not exist in the memory or is marked as invalid, the CPU detects
an error and the system program calls OB 19, if this is loaded. If
OB 19 is not loaded, the CPU changes to the STOP mode. A zero is
entered in the DBA and DBL registers.
Note
OB 19 is called both when a logic or data block is not loaded.
You can read system data register RS 75 to determine (via the
STEP 5 program) which type of error occurred. The contents of
RS 75 are as follows:
- for a KB error:
0101H,
- for a KDB error:
0904H.
CPU 948 Programming Guide
C79000-G8576-C848-04
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