Optimizing Driver to PLC Communications

The ABCLX driver connects to the ControlLogix system devices using the Ethernet/IP network. To know the connection state of all configured PLCs, the driver supports the use of Status Tags for the system and for each device.

To minimize network traffic, the ABCLX driver also supports the use of different scan rates for different devices, and active and inactive devices. See Status Tags and Scan Rates.

Note: The ABCLX driver maintains an internal tag cache and services Plant SCADA DCB requests from the internal cache.

You can also adjust the System Overhead Time Slice in the PLC to the highest value possible. The higher you make the number, the better the MSG performance will be. However, this may have an adverse performance impact on the control program being executed by the ControlLogix controller.

The System Overhead Time Slice in the PLC is adjusted from the ControlLogix programming software by right clicking on the controller and navigating to the "Controller Properties" then click on the "Advanced" tab.

It is also good engineering practice to arrange your variable.dbf by IO Device then DataType. This allows Plant SCADA to create requests by blocking the same data types within an IO Device together.