Time Delay Interrupt Ob; Cyclic Interrupt Ob; Hardware Interrupt Ob - Siemens S7-1200 System Manual

4.1.3.3

Time delay interrupt OB

Time delay interrupt OBs execute after a time delay that you configure.
Time delay interrupt events
You configure time delay interrupt events to occur after a specified delay time has expired.
You assign the delay time with the SRT_DINT instruction. The time delay events interrupt the
program cycle to execute the corresponding time delay interrupt OB. You can attach only
one time delay interrupt OB to a time delay event. The CPU supports four time delay events.
Table 4- 4
Input
Sign
4.1.3.4

Cyclic interrupt OB

Cyclic interrupt OBs execute at a specified interval. You can configure up to a total of four
cyclic interrupt events, with one OB corresponding to each cyclic interrupt event.
Cyclic interrupt events
The cyclic interrupt events allow you to configure the execution of an interrupt OB at a
configured cycle time. You configure the initial cycle time when you create the cyclic interrupt
OB. A cyclic event interrupts the program cycle and executes the corresponding cyclic
interrupt OB. Note that the cyclic interrupt event is at a higher priority class than the program
cycle event.
You can attach only one cyclic interrupt OB to a cyclic event.
You can assign a phase shift to each cyclic interrupt so that the execution of cyclic interrupts
with the same scan time can be offset from one another by the phase offset amount. The
default phase offset is 0. To change the initial phase shift, or to change the initial scan time
for a cyclic event, right click the cyclic interrupt OB in the project tree, select "Properties"
from the context menu, then click "Cyclic interrupt", and enter the new initial values. You can
also query and change the scan time and the phase shift from your program using the Query
cyclic interrupt (QRY_CINT) and Set cyclic interrupt (SET_CINT) instructions. Scan time and
phase shift values set by the SET_CINT instruction do not persist through a power cycle or a
transition to STOP mode; scan time and phase shift values return to the initial values
following a power cycle or a transition to STOP. The CPU supports a total of four cyclic
interrupt events.
4.1.3.5

Hardware interrupt OB

Hardware interrupt OBs execute when the relevant hardware event occurs. A hardware
interrupt OB interrupts normal cyclic program execution in reaction to a signal from a
hardware event.
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
Start information for a time delay interrupt OB
Data type Description
Word Identifier passed to triggering call of SRT_DINT
PLC concepts
4.1 Execution of the user program
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