Technical data

Table Of Contents
Organization Blocks
System Software for S7-300/400 System and Standard Functions - Volume 1/2
A5E00709327-01
1-15
If a hardware interrupt is triggered and its OB is currently active due to a hardware
interrupt from another module, the new request is recorded and the OB processed
when it is free.
You can disable or delay and re-enable hardware interrupts using SFCs 39 to 42.
You can assign parameters for the hardware interrupts of a module not only with
STEP 7 but also with SFCs 55 to 57.
Local Data for Hardware Interrupt OBs
The following table describes the temporary (TEMP) variables for a hardware
interrupt OB. The variable names are the default names of OB40.
Variable Type Description
OB40_EV_CLASS BYTE Event class and identifiers:
B#16#11: interrupt is active
OB40_STRT_INF BYTE
B#16#41: interrupt via interrupt line 1
B#16#42: interrupt via interrupt line 2
(only with an S7-400)
B#16#43: interrupt via interrupt line 3
(only with an S7-400)
B#16#44: interrupt via interrupt line 4
(only with an S7-400)
B#16#45: WinAC: interrupt triggered via PC
OB40_PRIORITY BYTE Assigned priority class: defaults 16 (OB40) to 23 (OB47)
OB40_OB_NUMBR BYTE OB number (40 to 47)
OB40_RESERVED_1 BYTE Reserved
OB40_IO_FLAG BYTE Input module: B#16#54
Output module: B#16#55
OB40_MDL_ADDR WORD Logical base address of the module that triggers the
interrupt
OB40_POINT_ADDR DWORD For digital modules:
bit field with the statuses of the inputs on the module(Bit
0 corresponds to the first input)
The assignment the bits from OB40_POINT_ADDR to
the channels in the module can be found in the
description for the given module.
For analog modules:
Bit field, informing which channel has exceeded which
limit (for detailed info on the structure refer to /71/ or
/101/).
For CPs or IMs:
Module interrupt status (not user relevant)
OB40_DATE_TIME DATE_AND_TI
ME
DATE_AND_TIME of day when the OB was called
Note
If you are using a DPV1 capable CPU you can obtain additional information on the
interrupt with the help of SFB 54 "RALRM" which exceeds the start information of
the OB. This also applies when you operate the DP Master in S7 compatible mode.