Technical data

Table Of Contents
SFCs for Handling Interrupts and Asynchronous Errors
System Software for S7-300/400 System and Standard Functions - Volume 1/2
A5E00709327-01
12-5
12.3 Enabling the Processing of New Interrupts and
Asynchronous Errors with SFC 40 "EN_IRT"
Description
With SFC 40 "EN_IRT" (enable interrupt), you enable the processing of new
interrupts and asynchronous errors that you previously disabled with SFC 39
"DIS_IRT." This means that if an interrupt event occurs, the operating system of
the CPU reacts in one of the following ways:
It calls an interrupt OB or asynchronous error OB.
It triggers the standard reaction if the interrupt OB or asynchronous error OB is
not programmed.
Parameter Declaration Data Type Memory Area Description
MODE INPUT BYTE I, Q, M, D, L,
constant
Specifies which interrupts and
asynchronous errors will be enabled.
OB_NR INPUT INT I, Q, M, D, L,
constant
OB number
RET_VAL OUTPUT INT I, Q, M, D, L If an error occurs while the function is
active the return value contains an error
code.
MODE
MODE
(B#16#...)
Meaning
0 All newly occurring interrupts and asynchronous errors are enabled.
1 All newly occurring events belonging to a specified interrupt class are enabled. Identify the
interrupt class by specifying it as follows:
Time- of-day interrupts: 10
Time-delay interrupts: 20
Cyclic interrupts: 30
Hardware interrupts: 40
Interrupts for DPV1: 50
Multicomputing interrupts: 60
Redundancy error interrupts: 70
Asynchronous error interrupts: 80
2 All newly occurring events of a specified interrupt are enabled. You specify the interrupt
using the OB number.