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CHAPTER 8 FUNCTIONS
8
8.
7
Lo
opback F
unct
ion
(1) Setting procedure
1.
Configure the network in ring topology.
2.
Select "Use" under "Loopback Function Setting" in the network configuration settings for the
master station.
Project window
[Parameter]
[Network Parameter]
[Ethernet/CC IE/MELSECNET]
button
[CC IE Field Configuration]
[Supplementary Setting]
(2) Program that detects loopback station numbers (master operating station only)
By detecting loopback station numbers, a faulty station can be found.
Whether loopback is being performed or not can be checked using Loopback function setting status (SB0078)
and Loopback status (SB0065) of the master operating station.
Program that stores loopback station numbers to D1000 and D1001
For details on link special relay (SB) and link special register (SW), refer to the following.
Page 473, Appendix 3, Page 493, Appendix 4
(3) Precautions
(a) Master/local module and GX Works2 that support the function
Before using the loopback function, check the serial number of the master/local module on the master station
and the GX Works2 version. (
(b) Loopback function setting and network configuration
For ring topology, select "Use" in "Loopback Function Setting". For network topology other than ring topology,
clear the checkbox.
If the loopback function setting and the network configuration are inconsistent, an error may occur in all stations
and data link cannot be performed.
Select the checkbox.
Select the checkbox.
Ex.