Mitsubishi MELSEC Q Series Reference Manual page 523

APPX - 27
POINT
(1) The programmable controller CPU performs only one of the above operations
during END processing.
If the programming tool and modules simultaneously access the
programmable controller CPU, the newly-requested processing has to wait
until the current processing ends. In this case, the number of scans required
for the processing increases even more.
(2) To reduce the time intervening in the scan time, adjust the time value under
"Service processing setting" on the PLC System setting tab of PLC parameter.
For "Service processing setting", refer to the User's Manual (Function
Explanation, Program Fundamentals) for the CPU module used.
(3) If the increase in scan time affects the operations of the programmable
controller CPU, access the CPU module multiple times by dividing the points.
(4) If File close (Command: 182A) is executed during STOP, the programmable
controller CPU will have to respond after the contents of the program cache
memory are transferred to the program memory. This causes delay in the
response to the command.
APPENDICES
APPX - 27