Mitsubishi Electric MELSEC-Q00U(J)CPU

183
CHAPTER 3 FUNCTIONS
3
3.13 Execution Time Measurement 3.13.3 Scan time measurement
• When only the start step is executed
The specified end step is not executed by the JMP instruction.
• When the end step is executed before the start step
The start step is specified as the next step of the CALL instruction and the end step is specified in a
subroutine program executed by the CALL instruction.
• When the IRET instruction, FEND instruction, BREAK instruction, or RET instruction is specified for the
end step
In an interrupt program by I31, the IRET instruction is specified for the end step.
Ex.
0
3
5
7
10
12
13
P0
End step: 9
Start step: 3
JMP P0
END
The specified end step
is not executed due to
the JMP instruction.
Ex.
0
3
5
6
9
P0
End step: 8
Start step: 3
FEND
CALL P0
RET
The start step is executed
after the end step by the
CALL instruction.
Ex.
0
1
3
7
10
12
I31
FEND
END
IRET
EI
4
13
End step: 12
Start step: 4
When the scan time in an
interrupt program is measured,
do not specify the IRET
instruction for the end step.