6. BASIC INSTRUCTIONS
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MELSEC-A
Operation Error If the IRET instruction is executed prior to the run of interrupt program, the PC stops
its operation.
Program Example EI , DI
Disable/enable program of the run of interrupt program by DI and EI.
Sequence program
IRET
FEND
IRET
I13
When IRET instruction is executed,
PC stops operation.
Interrupt program
CJ P20
X000
0
4
5
10
X000
X003
DI
EI
11
CJ P10
Enables execution of interrupt
program when X0 is on and
disables execution of interrupt
program when X0 is off.
P20
P10
• Coding
0 LD X000
1 CJ P10
4 DI
5 P10
6 LDI X000
7 CJ P20
10 EI
11 P20
12 LD X003
……….