Technical data

Table Of Contents
Organization Blocks
System Software for S7-300/400 System and Standard Functions - Volume 1/2
1-16
A5E00709327-01
1.7 Status Interrupt OB (OB 55)
Note
A status interrupt OB (OB 55) is only available for DPV1 capable CPUs.
Description
The CPU operating system calls OB55 if a status interrupt was triggered via the
slot of a DPV1 slave. This might be the case if a component (module or rack) of a
DPV1 slaves changes its operating mode, for example from RUN to STOP. For
precise information on events that trigger a status interrupt, refer to the
documentation of the DPV1 slave‘s manufacturer.
Local data of the status interrupt OB
The table below contains the temporary (TEMP) variables of the status interrupt
OB. Selected variable names are the default names of OB55.
Variable Data type Description
OB55_EV_CLASS BYTE Event class and identifiers:
B#16#11 (upcoming event)
OB55_STRT_INF BYTE B#16#55: Status interrupt for DP
B#16#58: Status interrupt for PN IO
OB55_PRIORITY BYTE Configured priority class, default values 2
OB55_OB_NUMBR BYTE OB number (55)
OB55_RESERVED_1 BYTE Reserved
OB55_IO_FLAG BYTE Input module: B#16#54
Output module: B#16#55
OB55_MDL_ADDR WORD logical base address of the interrupt triggering component
(module)
OB55_LEN BYTE Data block length supplied by the interrupt
OB55_TYPE BYTE ID for the interrupt type "Status interrupt"
OB55_SLOT BYTE slot number of the interrupt triggering component (module)
OB55_SPEC BYTE Specifier
Bit 0 to 1: Interrupt specifier
bit 2: Add_Ack
Bit 3 to 7: Seq. no.
OB55_DATE_TIME DATE_AND_TIME Date and time at which the OB was called
Note
You can obtain the full auxiliary information on the interrupt the DP message frame
contains by calling SFB54 "RALRM" with OB55.