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MELSEC-Q
10 DEVICES
1) Switching over local devices by setting ON/OFF for a special relay
(SM776)
SM776
OFF
Executes calculation by the local devices that are used by the file
where the sub-routine program was called
ON
Executes calculation by the local devices that are used by the file
where the sub-routine program is stored.
[Operation at "SM776 : OFF"]
CALL P100
X0
INCP D0
X2
END
Local devices used by
the file name: ABC
File name: ABC
Local devices used by
the file name: DEF
File name: DEF
(Standby program)
RET
P100
Sub-routine
program
Read/write of the
local devices
Execution of the
sub-routine program
[Operation at "SM776 : ON"]
CALL P100
X0
INCP D0
X2
END
Local devices used by
the file name: ABC
File name: ABC
Local devices used by
the file name: DEF
File name: DEF
(Standby program)
RET
P100
Sub-routine
program
Read/write of the
local devices
Execution of the
sub-routine program
2) Cautions
• If SM776 is ON, the local device data is read when the sub-routine
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 sub-routine program is executed once with the setting of "SM776:
ON". (See Section 10.13.1)
• 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, see Appendix 1.