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Allen-Bradley ControlLogix Ethernet Driver Help


protocol depends on the application at hand. When performance is crucial, it is worth performing Logical Blocking and Logical Non-Blocking trials to determine which is the best protocol mode for the application. Symbolic protocol is not necessary since it will never meet the performance caliber of either of the other protocol modes. It is shown here for the sake of the example.

Measures were taken to optimize communications using the tips outlined in Optimizing Your Communications. Most notably, tag division was used to place the Logical Blocking type tags in a device assigned Logical Blocking and the Logical Non-Blocking type tags in a device assigned Logical Non-Blocking. Furthermore, both devices resided on the same channel. The results show an improvement over using Logical Blocking on a single device. This is because some tags lend themselves better to one protocol mode over another. For example, reading an entire COUNTER will benefit from Logical Blocking over Logical Non-Blocking since it's much faster reading the COUNTER as a block then as individual members.

Measures were also taken to optimize the application by placing devices on their own channel. Using the devices created in the previous trial, a Logical Blocking device was placed on one channel and a Logical Non-Blocking device on another. The results show improvement over the single channel/multiple devices scenario from the previous trial. This reinforces the idea that performance is improved by having as few devices per channel and as many channels as necessary.

After using these three optimization methods, the project has an 827% performance increase over Allen-Bradley ControlLogix Ethernet Driver version earlier than 4.6.0.xx. Tag division and multiple channels improved the performance by 107%. The performance increases will be more apparent with larger projects.

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