Technical data

Table Of Contents
Organization Blocks
System Software for S7-300/400 System and Standard Functions - Volume 1/2
A5E00709327-01
1-25
1.14 CPU Redundancy Error OB (OB72)
Note
The CPU redundancy error OB (OB72) exists only with H CPUs.
Description
The operating system of the H CPU calls OB72 when one of the following events
occurs:
Loss of CPU redundancy
Reserve-master switchover
Synchronization error
Error in a SYNC module
Updating aborted
Comparison error (for example, RAM, PIQ)
OB72 is executed by all CPUs that are in the RUN or STARTUP mode following a
suitable start event.
Local Data of the CPU Redundancy Error OB
The following table contains the temporary (TEMP) variables of the CPU
redundancy error OB. The default names of OB72 have been used as the variable
names.
Variable Type Description
OB72_EV_CLASS BYTE Event class and IDs:
B#16#78: outgoing event
B#16#73, B#16#75, B#16#79: incoming event
OB72_FLT_ID BYTE Error code (possible values: B#16#01, B#16#02,
B#16#03, B#16#20, B#16#21, B#16#22,
B#16#23, B#16#31, B#16#33, B#16#34,
B#16#40, B#16#41, B#16#42, B#16#43,
B#16#44, B#16#50, B#16#51, B#16#52,
B#16#53, B#16#54, B#16#55, B#16#56,
B#16#C1, B#16#C2)
OB72_PRIORITY BYTE Priority class; can be assigned via STEP 7
(hardware configuration)
OB72_OB_NUMBR BYTE OB number (72)