Technical data

Table Of Contents
Organization Blocks
System Software for S7-300/400 System and Standard Functions - Volume 1/2
1-50
A5E00709327-01
1.23 Communication Error Organization Block (OB87)
Description
The operating system of the CPU calls OB87 whenever an event occurs that was
caused by a communication error.
The CPU does not change to the STOP mode if OB87 has not been programmed.
You can disable or delay and re-enable the communication error OB using SFCs
39 to 42.
Local Data for OB87
The following table describes the temporary (TEMP) variables for the
communication error OB. The variable names are the default names of OB87.
Variable Type Description
OB87_EV_CLASS BYTE Event class and identifiers: B#16#35
OB87_FLT_ID BYTE Error code:
(possible values: B#16#D2, B#16#D3, B#16#D4,
B#16#D5, B#16#E1, B#16#E2, B#16#E3, B#16#E4,
B#16#E5, B#16#E6)
OB87_PRIORITY BYTE Priority class; can be assigned via STEP 7 (hardware
configuration)
OB87_OB_NUMBR BYTE OB number (87)
OB87_RESERVED_1 BYTE Reserved
OB87_RESERVED_2 BYTE Reserved
OB87_RESERVED_3 WORD Depends on the error code
OB87_RESERVED_4 DWORD Depends on the error code
OB87_DATE_TIME DATE_AND_TIME DATE_AND_TIME of day when the OB was called