Access via network variables

In this case, the CPx8xx Bus Coupler is linked into 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). Access from host PC to the I/O channels of the Bus Coupler is implemented by the use of network variables.

Setting up RT Ethernet:

A 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.

 

The cycle time of the RT Ethernet device determines the cycle time for the data exchange with the Bus Coupler. The recommended cycle time for the data exchange with the Bus Coupler is 50 to 80 milliseconds (see also Cycle time for data exchange).

One or more network variable(s) are added to the host PC Subscriber corresponding with the network variables configured on the client. In the dialogue window which appears, after the Publisher computer has been searched for, a list of all Publisher variables is displayed and the corresponding variable can be added to the Subscriber.

 

The host PC network variable can now be linked with PLC or task variables.

 

Accessing Bus Coupler outputs:

For accessing the outputs of the Bus Coupler a "Subscriber" is added to the client RT Ethernet device and a "Publisher" to the host RT Ethernet device.

One or more network variable(s) are added to the host PC Publisher according to the PLC or task variables to be mapped on the Bus Coupler outputs. The Publisher network variable, "Pub-Var CPX8XX Outputs" in this example, is linked with the corresponding PLC or task variables.

 

One or more network variable(s) are added to the client Subscriber corresponding with the network variables configured on the host PC. In the dialogue window which appears, after the Publisher computer has been searched for, a list of all Publisher variables is displayed and the corresponding variable can be added to the Subscriber.

 

The client network variable now can be linked with the output variables of the Bus Coupler.

 

The cycle time of the RT Ethernet device determines the cycle time for the data exchange with the Bus Coupler. The recommended cycle time for the data exchange with the Bus Coupler is 50 to 80 milliseconds (see also Cycle time for data exchange).