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10.14 Convenient Usage of Devices
10.14.2 Local devices
10
DEVICE EXPLANATION
(c) Precautions
• If SM776 is ON, the local device data is read when the subroutine program is
called and the local device data is saved after the execution of the RET
instruction. Accordingly, scan time is elongated by the time as when a
subroutine program is executed once with the setting of "SM776: ON".
• ON/OFF setting of SM776 is enabled in CPU modules.
Setting in file units is not enabled.
• If the ON/OFF setting of SM776 is changed while a sequence program is
executed, the control is made according to the information after change.
Remark
For details on SM776, refer to Appendix 1.
(6) Using local devices when executing an interrupt/fixed scan execution
type program
It is possible to use local devices in the file where an interrupt/fixed scan execution
type program is stored when executing an interrupt/fixed scan execution type
program.
The local devices can be set available/unavailable by special relay "SM777" ON/OFF
setting.
(a) Operation at "SM777 : OFF"
Table10.31 Switching over local devices by setting ON/OFF for a special relay (SM777)
SM777
Operation
OFF
Executes operation with the local devices in the file which was executed
before the execution of the interrupt/fixed scan execution type program.
ON
Executes operation with the local devices in the file where the interrupt/fixed
scan execution type program is stored.
Figure 10.108 When SM777 is OFF
X0
X2
D1
D0
DECP
INCP
END
Occurrence
of interrupt
IRET
I0
Interrupt program
Local devices used
by the file name: ABC
Local devices used
by the file name: DEF
File name: ABC
File name: DEF
(Stand-by type program)
Execution of the
interrupt program
Read/write of the
local devices
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