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5.4.7
NCK hardware interrupts
5.4.7.1
General information on hardware interrupt OBs
If a hardware interrupt is triggered by a module during runtime, the hardware interrupt OB
defined in the associated event is triggered or entered in the queue depending on its priority.
● This allows you to react specifically in the PLC user program to events that are triggered by
various modules.
You can use the same or different hardware interrupt OBs for different hardware/module
events. When you assign the same hardware interrupt OB to different events, you must
distinguish between the triggering events in the program code of the hardware interrupt OB.
● The hardware interrupt mechanism is also used by the event-driven signal exchange (NCK
to PLC) to be able to respond to NCK events in the PLC program.
You must activate the event-driven signal exchange in the NCK properties. You should
assign an exclusive hardware interrupt OB during this. The hardware interrupt OB must
contain the call of LBP_NCKProcessIRT [FC3] and the queries for the occurrence of the
NCK events.
5.4.7.2
Transfer and acknowledgment time of NCK signals
Various events in the NCK are transferred to the PLC. These are accessible at different times
in the PLC user program, depending on their type, and are acknowledged at different times to
the NCK again. You can reconfigure this behavior for auxiliary functions as described in the
table.
When you activate hardware interrupts in the properties of the NCK and assign a hardware
interrupt OB, this assigned hardware interrupt OB is called for all NCK events. When multiple
events occur at the same time, a separate instance of the same hardware interrupt OB is
executed for each event.
All NCK signals that are accessible in the PLC user program are listed in the table below.
Signal type
Standard auxiliary function
Fast auxiliary function
(user-defined auxiliary func‐
tions with fast acknowledg‐
ment)
MCU commissioning: NC, PLC, Drive
Commissioning Manual, 02/2020, A5E47437618B AB
Handover to
Acknowledg‐
user
ment to NCK
Cycle OB
After cycle OB
Cycle OB
Immediately in
the hardware in‐
terrupt OB
(see note)
5.4 Creating a PLC program
Remark
Fast auxiliary functions (user-defined auxiliary func‐
tions with fast acknowledgment) are auxiliary functions
that are already acknowledged in the hardware inter‐
rupt OB in the NC before they are pending for process‐
ing in the cycle (cycle OB). This means the acknowl‐
edgment does not acknowledge the execution of the
PLC user function in this case.
Especially when fast auxiliary functions are output in
consecutive part program blocks there is no guarantee
that the reaction in the PLC user program is synchro‐
nous with the block. Acknowledgment is delayed in
such cases until after the cycle OB.
PLC commissioning
89
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