BECKHOFF CP-Link3 - Manual (Page 64)

Page 64
deterministically. The recommended cycle time for data exchange with the terminals at the Bus Coupler is still between
50 and 80 ms (see also cycle time for data exchange ).
Setting up RT Ethernet:
One network adapter of both the host PC and the client must be configured as an RT Ethernet device and added
to the I/O configuration (also see Configuration of RT Ethernet Devices ).
"Routing" must be switched on for this RT Ethernet device on both on host PC as well as on the client. In addition
the NetIds of each of the RT Ethernet devices must be entered respectively in the "Routes" tables (also see
Configuration of RT Ethernet Devices ).
Further configuration is carried out as described in 2.a with the exception that for communication with the "Virtual USB
Interface (Remote)" the NetId of the client RT Ethernet device will be added as target system (this differs from the normal
NetId).
3. Access via network variables (RT Ethernet)
In this case, the CPx8xx Bus Coupler is used on the client as a local USB device. The CP-Link 3 USB device server on
the client is configured accordingly via a "Use Local List" (also see Using USB devices locally on the client ). The access
from host PC to the I/O channels of the Bus Coupler is implemented by the use of network variables (also see Network
variables ).
Setting up RT Ethernet:
One network adapter of both the host PC and the client must be configured as an RT Ethernet device and added
to the I/O configuration (also see Configuration of RT Ethernet Devices ).
Accessing Bus Coupler inputs:
To access the inputs of the Bus Coupler a "Publisher" is added to the RT Ethernet Device on the client and a
"Subscriber" is added to the RT Ethernet device on the host PC.
One or more network variable(s) are added to the client’s Publisher accordingly to the inputs of the Bus Coupler to be
mapped. The publisher network variable, in this example "Pub-Var CPX8XX Inputs" is linked with the input variables of
the Bus Coupler.