Technical data

Table Of Contents
Organization Blocks
System Software for S7-300/400 System and Standard Functions - Volume 1/2
1-52
A5E00709327-01
1.24 Processing Interrupt OB (OB 88)
Description
The CPU operating system calls OB 88 after a program block execution is been
aborted. Examples of possible causes for this interruption may be:
the nesting depth of synchronous errors is too high
the nesting depth of block calls (U-Stack) is too high
Error during allocation of local data
If you have not programmed OB 88 and a program block execution is aborted, the
CPU goes into STOP mode (Event ID W#16#4570).
If program block execution is aborted in priority class 28, the CPU goes into STOP
mode.
You can disable, delay and enable the processing interrupt OB with the help of
SFCs 39 to 42.
Local data of the Processing Interrupt OB
The table below contains the temporary (TEMP) variables of the processing
interrupt OB. The default names of OB 88 was selected as variable name.
Variable Data type Description
OB88_EV_CLASS BYTE Event class and Ids: B#16#35
OB88_SW_FLT BYTE Error code
possible values:
B#16#71: the nesting depth of the nesting stack is
too high
B#16#72: the nesting depth of the master control
relay is too high
B#16#73: the nesting depth of synchronous errors
is too high
B#16#74: the nesting depth of block calls (U
stack) is too high
B#16#75: the nesting depth of block calls (B
stack) is too high
B#16#76: Error during allocation of local data
B#16#78: Unknown instruction
B#16#7A: Jump instruction with destination
outside of the block
Please refer to the operation list for your CPU to
determine which error codes apply to your CPU.
OB88_PRIORITY BYTE Priority class: 28
OB88_OB_NUMBR BYTE OB number (88)