409
COM
1
2
3
4
4
6
7
8
7.6
S
tructure cr
eation
instructions
7.6.10
COM
2) In cases where the remote station scan time is longer than the scan time of the host station, the COM instruction
used at the remote station side can avoid the occurrence of timing failure in which the data cannot be fetched,
as shown in (a).
3) When the COM instruction has been used at the other station, a link refresh will be performed each time that
station receives a command from the host station.
(6) If the scan time from the linked station is longer than the sequence program scan time at the host station, designating the
COM instruction at the host station will not increase the speed of data communications.
The programs in which the COM instruction cannot be used are shown below:
• Low-speed execution type programs
• Interrupt programs
• Fixed scan execution type programs
Operation Error
(1) There is no operation error in the COM instruction.
Refer to Page 407, Section 7.6.9. for the COM instruction of the following CPU modules.
• Basic model QCPU of serial No. 04121 or later
• High Performance model QCPU of serial No. 04011 or later
• Process CPU of serial No. 07031 or later
COM
Select refresh
7.6.10
COM
• Basic model QCPU: The serial number (first five digits) is
"04122" or later.
• High Performance model QCPU: The serial number (first five
digits) is "04012" or later.
• Process CPU: The serial number (first five digits) is "07032" or
later.
Setting
Data
Internal Devices
R, ZR
J \
U \G
Zn
Constants
Other
Bit
Word
Bit
Word
––
––
Step 0
COM instruction
COM instruction
COM instruction
END instruction
COM instruction
Lin
k
refresh can be performed
once in each of these intervals.
Sequence program
0
END
COM
Lin
k
scan
0 COM
END 0 COM
COM
0
END
END
Basic
Process
High
performance
Redundant Universal
LCPU
Ver.
Ver.
Ver.
COM
COM