It is possible to use latch devices or I/O devices (X/Y) for link refresh devices.
However, when using I/O devices (X/Y), use  I/O numbers (such as X1000 ~/Y1000~) that are not assigned to actual control.
Also, you can check the device allocation settings for refresh devices in GX Works3 by following the steps below.
 View > Docking Window > Device Assignment Confirmation of GX Works3 menu and specify the appropriate module number in [Mounting Position No.].
However, make the network configuration settings and link refresh settings in the CC-Link parameters beforehand.