Mitsubishi Electric MELSEC-Q00U(J)CPU User Manual page 184

(5) Precautions
(a) Measurement range setting
Set the measurement range so that "Start step < End step" is satisfied.
(b) Minimum unit of measurement time
The minimum unit of measurement time is 0.01ms.
If the measurement time is less than 0.01ms, 0.000ms is displayed.
(c) When steps are specified between the FOR and NEXT instructions
Scan time required to execute the program between the specified steps is measured.
(d) When only the start step is specified between the FOR and NEXT instructions
• CPU modules other than the High-speed Universal model QCPU and Universal model Process CPU
Since the start step is executed repeatedly, scan time cannot be measured. (Time values are not updated
on the Scan Time Measurement window of a programming tool.)
• High-speed Universal model QCPU and Universal model Process CPU
The High-speed Universal model QCPU and Universal model Process CPU recognize only the first start
step and ignores the second and later start steps. Scan time required to execute the program between the
first start step and the end step is measured.
(e) When scan time cannot be measured
Scan time cannot be measured for scans executed across multiple program files.
Scan time is not updated on the Scan Time Measurement screen in the following case.
• When the branch instruction is specified to the end step
The JMP instruction is specified to the end step.
Ex.
182
3
6
8
Since the start step is specified
between the FOR and NEXT
instructions, it will be executed
10
repeatedly.
11
0
Start step: 3
3
5
7
P0
10
FOR K2
Start step: 8
NEXT
End step: 13
End step: 6
JMP P0