Mitsubishi Electric L02SCPU User's Manual And Reference page 351

(4) When executing an interrupt/fixed scan execution type program
When the local device is used for an interrupt/fixed scan execution type program, turn on SM777 (Enable/disable
local device in interrupt program). The programs will not function properly if SM777 is turned off.
*1 The index register set as the local device uses the local device area for the program executed before the interrupt/fixed
scan execution type program, regardless of the on/off status of SM777.
Ex.
Operation when SM777 is turned on with the following setting
Program name
A
B
C
X
A
Execution program
For B
Local device
(1)Uses the program X local device.
(2)When an interrupt/fixed scan execution type program is executed during the END processing, the local device for Program C, which was
executed before the END processing, is read out and saved. Thus, the END processing time increases by the time required for the read and
save.
(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.)
(5) Clearing local device data
Local device data are cleared by the 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 from a programming tool.
Execute type
Scan
Scan
Scan
Fixed Scan
C
B
X
For B
For C
For X
(1)
CHAPTER 7 CONVENIENT USAGE OF DEVICES
Local device
A
END
B
X
For B
For C
For X
(1)
* 1
Not used
Used
Used
Used
C
END
X
For C
For X
(1)
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