Siemens SIMATIC S7-1200

Extended instructions
9.5 Interrupts
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
435
9.5.5
DIS_AIRT and EN_AIRT (Delay/enable execution of higher priority interrupts
and asynchronous error events) instructions
Use the DIS_AIRT and EN_AIRT instructions to disable and enable alarm interrupt
processing.
Table 9- 124 DIS_AIRT and EN_AIRT instructions
LAD / FBD
SCL
Description
DIS_AIRT();
DIS_AIRT delays the processing of new interrupt events. You can execute
DIS_AIRT more than once in an OB.
EN_AIRT();
EN_AIRT enables the processing of interrupt events that you previously disabled
with the DIS_AIRT instruction. Each DIS_AIRT execution must be cancelled by an
EN_AIRT execution.
The EN_AIRT executions must occur within the same OB, or any FC or FB called
from the same OB, before interrupts are enabled again for this OB.
Table 9- 125 Data types for the parameters
Parameter and type
Data type
Description
RET_VAL
OUT
Int
Number of delays = number of DIS_AIRT executions in the queue.
The DIS_AIRT executions are counted by the operating system. Each of these remains in
effect until it is cancelled again specifically by an EN_AIRT instruction, or until the current OB
has been completely processed. For example: if you disabled interrupts five times with five
DIS_AIRT executions, you must cancel these with five EN_AIRT executions before interrupts
become enabled again.
After the interrupt events are enabled again, the interrupts that occurred while DIS_AIRT was
in effect are processed, or the interrupts are processed as soon as the current OB has been
executed.
Parameter RET_VAL indicates the number of times that interrupt processing was disabled,
which is the number of queued DIS_AIRT executions. Interrupt processing is only enabled
again when parameter RET_VAL = 0.