1 - Check the IP addresses of the PLC and the STB module
2 - Try pinging the STB module and the PLC from the PC
If it is working:

3 - Check configuration of the Ethernet card in the Premium configuration:
With PL7 Pro and Unity , click on the Ethernet module and check the following parameters:
, The IO scanning box must be selected
In IP address: The IP address of the STB module has been correctly entered
In Unit ID: Enter the value 255
In RD ref slave: Enter the value 5391
In WD slave ref: Enter the value 0
Note:
On an STB module in Ethernet protocol, images of the NIM I/O are at fixed addresses:
Images of the outputs begin from address 40001 --> enter 0 in WR slave ref
Images of the inputs begin from address 45392 --> enter 5391 in RD slave ref

See example screen shot from Unity.

Released for: Schneider Electric UK