Mitsubishi Electric melsec q00ujcpu User Manual page 285

(4) Precautions
The following describes precautions when the service processing setting is configured.
1) For the following functions, scan time will be increased longer than the specified time during service
processing even if the service processing time specification is set.
• Online change
• Change T/C setting
• Local device monitor
• Program memory backup
• Writing to/reading from a file register (The scan time will be increased when the write or read size is
large.)
• Writing to/reading from the buffer memory of the intelligent function module (The scan time will be
increased when the write or read size is large.)
• Access to a network module
a) Diagnostic functions (CC IE Control diagnostics, MELSECNET diagnostics, Ethernet diagnostics,
CC-Link/ CC-Link/LT diagnostics)
b) Monitor function (Module access device, Link direct device)
2) Note that the scan time will be increased much longer if the CPU module receives multiple requests
simultaneously while the service processing count specification is set many.
3) When setting the service processing time much shorter than the scan time, the response performance of
service processing is extremely reduced. Set the service processing time with considering the time-out
time of a peripheral.
4) An error of -20
time.
6 - 134
s to +30 s occurs between the actual processing time and the set service processing