8 INSTRUCTIONS FOR DATA LINK
8.1 Network Refresh Instructions
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8
• When the ZCOM instruction is executed, the CPU module temporarily suspends processing of the sequence program and
conducts refresh processing of the network modules designated by Jn/Un. (For LCPU whose serial number (first five digits)
is "13011" or earlier, the designation by Jn cannot be made.)
• The ZCOM instruction does not perform the following processing.
• The ZCOM instruction can be used as many times as desired in sequence programs. However, note that each execution of
a refresh operation will lengthen the sequence program scan time by the amount of time required for the refresh operation.
• Designating "Un" in the argument enables the target designation of the intelligent function as well as the network modules.
In this case, the auto refresh is performed for the buffer memory of the intelligent function modules. (It replaces the FROM/
TO instructions.)
• Only with the Universal model QCPU and LCPU, interruption of processing is enabled during the execution of the ZCOM
instruction. However, when refresh data are used in an interrupted program, the data can split.
• Communication processing between CPU module and programming tool
• Monitor processing of other station
• Read processing of buffer memory of other intelligent function module by serial communication module.
• Low-speed cyclic data transmission of MELSECNET/H
Refresh
processing
Execution of ZCOM
instruction
END
Refresh
processing
Refresh
processing
Refresh
processing
Refresh
processing
END
Execution of ZCOM
instruction
Execution of ZCOM
instruction
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