Mitsubishi Electric melsec q00ujcpu User Manual page 47

(b) Programming order
When creating multiple interrupt programs, it is not necessary to set the interrupt pointer numbers in
ascending order.
(c) Before executing an interrupt program
Before executing the interrupt programs of the interrupt pointers I0 to I15, I28 to I31, I45, and I50 to
I255, enable interrupts with the EI instruction.
Remark
For details of the EI instruction, refer to the following.
QCPU Programming Manual (Common Instructions)
(d) Restrictions on programming
1) PLS and PLF instructions
The PLS and PLF instructions perform off processing in the next scan of which the instruction is
executed.
Therefore, the device which is turned on by the instruction remains on until the same instruction is
reexecuted.
X0
M0
Figure 2.10 Device turned on by the PLS instruction in the interrupt program
2) EI and DI instructions
During execution of an interrupt program, interrupts are disabled (DI) so that any other interrupt
processing will not be executed.
Do not execute the EI or DI instruction during interrupt program execution.
3) Timer (T) and counter (C)
Do not use the timer (T) and counter (C) in interrupt programs.
If more than one interrupts occur in one scan, the timer (T) in the interrupt program cannot
measure the time correctly.
If more than one interrupts occur in one scan, or depending on the status of the OUT C
instruction at the time of interrupt program execution, the counter (C) in the interrupt program
cannot measure the count correctly.
4) Instructions not available in interrupt programs
Refer to sections corresponding to each instruction in the following.
QCPU Programming Manual (Common Instructions)
2 - 8
X0
END 0 IO IRET END 0
ON
OFF
ON
OFF
Turns on by executing the PLS M0 instruction at the rise of X0.
X0
PLS M0 PLS M0
END 0 IO IRET END
Turns off by executing the
PLS M0 instruction.
0
ņ