Scan Time - Mitsubishi Electric A800 Programming Manual

3.7

Scan time

Scan time
Scan time is the time period from operation execution of a sequence program from step 0 until executing the next step 0.
The scan time is not constant in every scan but differs according to whether instructions used are executed or not.
Scan time check
The scan time from the END instruction to the next END instruction is measured inside the programmable controller and
stored in special registers SD520 (SD521), SD524 (SD525), and SD526 (SD527).
Device number
SD520
Current scan time
SD521
SD524
Minimum scan time
SD525
SD526
Maximum scan time
SD527
• Scan time accuracy
The accuracy of the scan time observed inside the programmable controller is ±2 ms.
For example, the actual scan time is within the range of 3 ms to 7 ms when data stored in SD520 is 5.

Scan time

END 0
Name
The scan time is stored at every END and is constantly updated.
SD520: Stores the ms places (Stored range: 0 to 65535)
SD521: Stores the μs places (Stored range: 0 to 900)
The minimum scan time is stored at every END.
SD524: Stores the ms places (Stored range: 0 to 65535)
SD525: Stores the μs places (Stored range: 0 to 900)
The maximum scan time is stored at every END.
SD526: Stores the ms places (Stored range: 0 to 65535)
SD527: Stores the μs places (Stored range: 0 to 900)
END 0
Sequence program
END processing
Timer/counter count processing
Self-diagnostic checks
Description
Scan time
Sequence program
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