Technical data

Table Of Contents
Organization Blocks
System Software for S7-300/400 System and Standard Functions - Volume 1/2
A5E00709327-01
1-17
1.8 Update Interrupt OB (OB 56)
Note
A update interrupt OB (OB 56) is only available for DPV1 capable CPUs.
Description
The CPU operating system calls OB56 if an update interrupt was triggered via the
slot of a DPV1 slave. This can be the case if you have changed the parameters for
the slot of a DPV1 slave (via local or remote access). For precise information on
events that trigger an update interrupt, refer to the documentation of the DPV1
slave‘s manufacturer.
Local data of the update interrupt OB
The table below contains the temporary (TEMP) variables of the update interrupt
OB. Selected variable names are the default names of OB56.
Variable Data type Description
OB56_EV_CLASS BYTE Event class and identifiers:
B#16#11 (upcoming event)
OB56_STRT_INF BYTE B#16#56: Update interrupt for DP
B#16#59: Update interrupt for PN IO
OB56_PRIORITY BYTE Configured priority class, default values 2
OB56_OB_NUMBR BYTE OB number (56)
OB56_RESERVED_1 BYTE Reserved
OB56_IO_FLAG BYTE Input module: B#16#54
Output module: B#16#55
OB56_MDL_ADDR WORD logical base address of the interrupt triggering component
(module)
OB56_LEN BYTE Data block length supplied by the interrupt
OB56_TYPE BYTE ID for the interrupt type "Update interrupt"
OB56_SLOT BYTE slot number of the interrupt triggering component (module)
OB56_SPEC BYTE Specifier
Bit 0 to 1: Interrupt specifier
bit 2: Add_Ack
Bit 3 to 7: Seq. no.
OB56_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 OB56.