Scan Time - Mitsubishi Electric 700 Series Programming Manual

3.7 Scan Time

(1) Scan time
A scan time is a time from when sequence program operation is executed from
step 0 until step 0 is executed again.
The scan time of each scan is not equal, and changes depending on whether the
used instructions are executed or not.
END
(2) Scan time confirmation
(a)The scan time from the END instruction to the next END instruction is timed in
the PLC, and stored into the special registers D9017 to D9019 in units of
10ms.
1) Data stored into special registers D9017 to D9019
• D9017 ........... Minimum value of scan time
• D9018 ........... Present value of scan time
• D9019 ........... Maximum value of scan time
2) Scan time accuracy
The accuracy of the scan time observed in the PLC is
For example, when the D9018 data is 5, the actual scan time is 40ms to
60ms.
Scan time
0
Fig 3.8 Scan Time
END 0
Sequence program
END processing
Timer/counter count processing
Self-diagnostic checks
Scan Time
10ms.
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