Technical data

SFCs for Handling Interrupts and Asynchronous Errors
System Software for S7-300/400 System and Standard Functions - Volume 1/2
A5E00709327-01
12-7
12.4 Delaying the Processing of Higher Priority Interrupts
and Asynchronous Errors with SFC 41 "DIS_AIRT"
Description
With SFC 41 "DIS_AIRT" (disable alarm interrupts), you delay the processing of
interrupt OBs and asynchronous error OBs which have a higher priority than that of
the current OB. You can call SFC 41 more than once in an OB. The SFC 41 calls
are counted by the operating system. Each of these calls remains in effect until it is
canceled again specifically by an SFC 42 "EN_AIRT" call or until the current OB
has been completely processed.
Once they are enabled again, the interrupts and asynchronous errors that occurred
while SFC 41 was in effect are processed as soon as they are enabled again with
SFC 42 "EN_AIRT" or as soon as the current OB has been executed.
Parameter Declaration Data Type Memory Area Description
RET_VAL OUTPUT INT I, Q, M, D, L Number of delays (= number of
SFC 41 calls)
Return Value
The following table shows the return value for SFC 41 that is output with the
RET_VAL parameter.
Return Value Description
n "n" shows the number of times that processing was disabled, in other words the
number of SFC 41 calls (interrupt processing is only enabled again when n = 0; see
Enabling the Processing of Higher Priority Interrupts and Asynchronous Errors with
SFC 42 "EN_AIRT").