8-3
ZCOM
1
2
3
4
6
6
7
8
8.1 Network refresh instructions
8.1.1 Refresh instruction for the designated module (S(P)/J(P)/G(P).ZCOM)
(2) The ZCOM instruction does not perform the following processing.
(a) Communication processing between CPU module and programming tool
(b) Monitor processing of other station
(c) Read processing of buffer memory of other intelligent function module by serial
communication module.
(d) Low-speed cyclic data transmission of MELSECNET/H
(3) PLC to PLC network*1
(a) When the scan time for the sequence program of host station is longer than the scan
time for the other station, the ZCOM instruction is used to ensure the data reception
from the other station.
(1) Example of data communications when the ZCOM instruction is not used
(2) Example of data communications when the ZCOM instruction is used
For details of the transmission delay time on the PLC to PLC network*1, refer to the
manual below:
• CC-Link IE Controller Network Reference Manual
• Q Corresponding MELSECNET/H Network System Reference Manual
(PLC to PLC network)
(b) When the link scan time is longer than the sequence program scan time, data
communications will not be faster even if the ZCOM instruction is used.
*1 : Controller network in CC-Link IE controller network.
Control station
program
Link scan
Normal station
program
0ENDEND
00
0END0END0END
Control station
program
0END0END0
ZCOM ZCOM ZCOM
Link scan
Normal station
program
0END 0 END 0 END
Sequence program 0END
ZCOM
Link scan
0
ZCOM
END 0
ZCOM ZCOM
0END
END