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COM
7.6.9 Refresh instruction (COM)
COM
Refer to Section 7.6.10 for the COM instruction of the following CPU modules.
• Basic model QCPU of serial No. 04122 or later
• High Performance model QCPU of serial No. 04012 or later
• Process CPU of serial No. 07032 or later
• Redundant CPU
• Universal model QCPU
Function
(1) Use the COM instruction when:
(a) It is desired to increase the speed of transmission/reception processing to/from the
remote I/O stations.
(b) It is desired to ensure reliable data transmission/reception with other stations that use
different scan times during the execution of the data link.
(2) The processing of the COM instruction differs depending on whether the special relay
SM775 is ON or OFF.
• When SM775 is OFF: Performs auto refresh and communication with a peripheral
device *
1
*
2
• When SM775 is ON: Performs communication with peripheral device only *
1
*1: The following processing is performed in communication with peripheral device:
• Monitor processing of other stations
• Read processing by the serial communications module of the buffer memory of another intelligent
function module
*2: The auto refresh includes the following processing:
• Refresh of MELSECNET/10H
• CC-Link refresh
• Auto refresh of intelligent function modules.
Setting
Data
Internal Devices
R, ZR
J\
U\G
Zn Constants Other
Bit Word Bit Word
–– ––
Basic
Process
High
performance
Redundant
Universal
COM
COM