Mitsubishi Electric MELSEC-Q Series User Manual page 46

4 SEQUENCE PROGRAM CONFIGURATION & EXECUTION
CONDITIONS
Interrupt factor
Interrupt program
execution
Network refresh
execution
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3) Interruption during a network refresh:
If an interrupt factor occurs during a network refresh operation, the
network refresh operation is suspended, and the interrupt program is
executed.
This means that "assurance of blocks in cyclic data at each station"
cannot be secured by using a device designated as a destination of
link refresh operation on the MESSECNET/H Network System.
10ms
Fig.4.4 Interruption during Network Refresh Operation
4) Interruption during END processing:
If an interrupt factor occurs during an END processing waiting period
during constant scanning, the interrupt program corresponding to that
factor will be executed.
(c) See Section 10.6.1 for details regarding index register processing when
switching to an interrupt program from a main routine program or sub
routine program.
(4) High-speed execution of an interrupt program and overhead time
By default, the Basic model QCPU "hides and restores an index register" when
executing an interrupt program.
The above-listed processes are not performed if an option to "Execute at a High
Speed" is selected in the PLC System Setting sheet of the PLC Parameter dialog box.
This will make it possible to shorten the duration of overhead time required for
execution of an interrupt program.
Refer to Section 11.2 for the overhead time of an interrupt program.
REMARK
1: For details regarding the IMASK and EI instructions, refer to the "QCPU (Q mode)/
QnACPU Programming Manual (Common Instructions).
2: See Section 10.10 for details regarding the priority ranking of interrupt programs.
3: For assurance of station unit blocks in cyclic data, see the "MELECNET/H
Network System Reference Manual."
10ms 10ms
Network refresh operation is suspended,
and the interrupt program is executed.
MELSEC-Q
3
10ms
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