Modbus Plus X-Link Driver User’s Guide
4.3 Destination Accesses
The Modbus Plus driver supports three possible destination accesses.
The first destination defines a local address which allows any device on the Modbus Plus network to read the data from the X-Link. This type of destination can be used to allow a PLC to read back the data it has written. Programming must be provided on the remote device to initiate the read.
The second type of destination access supported by the Modbus Plus driver is an X-Link initiated write. This destination defines an external address which the X-Link uses to write the data to a remote node on the network. This access also requires the user to specify when to write the data. This type of data destination does not require any programming in the remote node and can avoid wasting network bandwidth that would be consumed by having the PLC poll the data.
The last type of destination access supported is global data. The X-Link writes the values into the global data table for the Modbus Plus station that is X-Link.
