Mitsubishi Electric MELSEC-Q00U(J)CPU User Manual page 430

(a) Precautions
• When SM777 is on, local device data are read out before execution of an interrupt/fixed scan execution
type program, and the data are saved after execution of the IRET instruction.
Because of this, the scan time is increased if one interrupt/fixed scan execution type program is executed
with SM777 set to on.
• The on/off status of SM777 is set for each CPU module.
It cannot be set for each file.
• For the local device monitoring, the target local device is monitored by switching the selection of
corresponding program manually. When SM777 is off, when an interrupt occurred immediate after the
switch processing, monitoring target local device is monitored. (The local device for the program executed
prior to the interrupt (the program immediate before END) is not monitored.)
Remark
For details of SM777, refer to the following.
QCPU User's Manual (Hardware Design, Maintenance and Inspection)
(7) Clearing local device data
Local device data is cleared by either of the following:
• When the CPU module is powered off and then on or is reset
• When the CPU module status is changed from STOP to RUN
Local device data cannot be cleared using a programming tool.
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