328
6 BASIC INSTRUCTIONS
6.6 Program Execution Control Instructions
DI, EI, IMASK
■When the High Performance model QCPU/Process CPU/Redundant CPU/Universal model
QCPU or LCPU is used
■DI
• Disables the execution of an interrupt program until the EI instruction has been executed, even if a start cause for the
interrupt program occurs.
• A DI state is entered when power is turned ON or when the CPU module is reset.
■EI
• The EI instruction is used to clear the interrupt disable state resulting from the execution of the DI instruction, and to create
a state in which the interrupt program designated by the interrupt pointer number enabled by the IMASK instruction and the
fixed cycle execution type program can be executed.
• When the IMASK instruction is not executed, I32 to I47 are disabled.
(S): Head number of the devices where the interrupt mask data is stored (BIN 16 bits)
Setting
data
Internal device R, ZR J\ U\G Zn Constant Others
Bit Word Bit Word
(S)
IMASK
DI
EI
Sequence program
SIMASK
DI
EI
Sequence program
DI
Sequence program
EI
In
FEDN
Interrupt programs
Even if a cause of interrupt occurs during
the execution of the sequence program
between the DI and EI instructions,
execution of the interrupt program is
suspended until the processing of the
sequence program is completed.
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