Estimating your Allen-Bradley (A-B) Logix controller's Ethernet/IP bandwidth using Rockwell's free Ethernet/IP capacity tool


When designing or upgrading a system which relies on a network, bandwidth is always a concern.

But for Rockwell's CompactLogix and ControlLogix on an Ethernet/IP network there is a free, easy to use utility to help you size your system.

Rockwell's Ethernet/IP Capacity Tool:

Rockwell's Ethernet/IP Capacity Tool, which can be freely downloaded here or here, allows the user to select a platform, add different types of I/O and network devices, and then calculates how many CIP and TCP connections are consumed along with the packets per second (PPS) needed to service the network.

Below I'll walk you step by step through using this tool to calculate the connections and PPS requirements of a sample system:

Step 1: Using this link, download and install the Ethernet/IP Capacity Tool. Once installed, launch it from the Windows Start Menu as shown below:

Using the EthernetIP Capacity Tool 1

Step 2: When the tool opens, you'll see nine dropdown lists and boxes (as seen below:)

Using the EthernetIP Capacity Tool 2

Step 3: To start sizing our sample system we'll need to choose a Programmable Controller from the top center dropdown. In this example we'll choose a CompactLogix L24ER:

Using the EthernetIP Capacity Tool 3

Step 4: Now in the top left dropdown (above the “Node Group 1” box) we'll select “Point I/O Rack” as shown below:

Using the EthernetIP Capacity Tool 4

Step 5: Change the “No. Racks” for the Point I/O to 4:

Using the EthernetIP Capacity Tool 5

Step 6: Next. check the “Analog / Specialty Modules” box and change the first “No. of Analog Modules” to 2 as shown:

Using the EthernetIP Capacity Tool 6

Step 7: With the four Point I/O racks added, press the “Compute” button found half way down on the left side of the program. This returns the number of connections and  PPS used, as well as how many are remaining. Since we are still within our limits all the results are green:

Using the EthernetIP Capacity Tool 7

Step 8: Let's add some VFD's to our system. Select the dropdown above “Node Group 2” and choose “PowerFlex 525 Drive” from the list:

Using the EthernetIP Capacity Tool 8

Step 9: Now, look under the picture of the drive you have just added – you have a field to enter the number of drives (on the left) and the update rate (on the right.) In the left hand box under the drive's picture change the number of drives to 4 as shown. Note: Sometimes the text doesn't display in the correct location, as is the case below. Hey, it's free right?

Using the EthernetIP Capacity Tool 9

Step 10: Press the “Compute” button. The software reports back that we have exceeded the limit of 8 Ethernet/IP I/O drops for the L24. However, we only have 8?

Using the EthernetIP Capacity Tool 10

Step 11: To resolve the above issue, uncheck the “Switch IGMP Snooping with Querier.” Read the popup and then press “OK:”

Note: This does not mean you can't have an IGMP switch in this system, it only means that if the switch was added to the RSLogix5000 I/O Tree it would consume one of the L24's eight Ethernet I/O racks. In our example, we won't be adding the switch to the I/O Tree (in order to allow our L24 to have 4 racks of Point I/O and 4 PF525 drives.)

Using the EthernetIP Capacity Tool 11

Step 12: Press the “Compute” button again and you should now see yellow which indicates we have reached (but not exceeded) one of the system limits:

Using the EthernetIP Capacity Tool 12

Step 13: Next we'll add some HMI's. In the “Node Group 3” section,n select the PanelView Plus from the dropdown, read the popup and press “OK:”

Using the EthernetIP Capacity Tool 13

Step 14: Change the number of HMI's to 10 and press “Compute”

Using the EthernetIP Capacity Tool 14

Step 15: As you can see below, event though our L24 has no more room for Ethernet/IP I/O, it still has plenty of bandwidth for HMI's. In fact, this is a key feature of the entire line of 5370 CompactLogix controllers.

Using the EthernetIP Capacity Tool 15

Step 16: To see how the older line of CompactLogix controllers were much more limited when it came to the number of HMI's that could be connected, lets change the L24 to an L35E (as shown below:)

Using the EthernetIP Capacity Tool 16

Step 17: Now press “Compute.” You'll see red as we have greatly exceeded the connection limit of this older model:

Using the EthernetIP Capacity Tool 17

Step 18:To find a working number of HMI's for this system, reduce the number of PanelView Plus units down until you can press “Compute” and not have a red result for CIP connections. In my test below I maxed out at three PVPlus units.

Using the EthernetIP Capacity Tool 18

Step 19: Now that our design is complete we can save our work as either a native file, as a picture, or in Excel format.

Using the EthernetIP Capacity Tool 19


I hope the above step by step walkthrough of using the Ethernet/IP Capacity Tool is helpful. If you have any comments or questions on this tool please feel free to leave using the “post a comment or question” link below.


Shawn Tierney
Automation Instructor and Blogger
If you enjoyed my article, you may like my courses at

Old Comment:

  1. Do you have any suggestions on what to use for a GuardLogix system with an EN2T that goes out to a big switch, that then goes out to 18 Point I/O modules, 9 Emerson Servos, 3 ABB robots, 2 Henrob Riveters, and 6 Murr Cube67 systems?

  2. Good morning controlsgirl,

    You can still use this Ethernet IP Capacity Tool as it does have a “generic device” selection you can use with third party devices.

    Hope this helps,

    Shawn Tierney

    If you enjoyed reading my article you may also like my affordable training courses at

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