Out of Bandwidth Connection

celso3093

Member
Join Date
May 2021
Location
Brazil
Posts
16
Hello!

I am expanding a plant and IÂ’ll have to add 27 powerflex 525 that communicate through Ethernet/IP. IÂ’ve already added 12 of them.

The problem is that since the 9th driver, every time I try to add a new one, after configuring IP address and subnet mask, I get a “(Code 16#0302) Connection Request Error: Out of communication bandwidth” in the RSLogix 5000. In order to communicate to the new driver, the solution that I found is to increase the RPI (Requested Packet Interval) of ALL the drivers in my project.

I am adding the drivers under a 1756-ENET/B that communicates right now with another 1756-ENET/B, 13 1794-AENT and the 12 recently added drivers.

IÂ’m a little lost here. Could anyone give me a hint of something to check or anything to do?


Thank you all!
 
Sorry cant help on the exact error code. But Id try adding the planned configuration through integrated architecture builder first.
 
What is your RPI for the drives? How much data are they sending?
 
What is your RPI for the drives? How much data are they sending?

The RPI is set to 120 ms. It was originally set to 80 ms.

I dont know where it shows the amount of data that is transfered in terms of bytes, but the parameters that the drivers are set to send are Drive Status (15 booleans and 1 INT) Output frequency (INT) and output current (INT).

The parameters that the drivers are set to receive are Logic Command (16 booleans and 1 INT) and Freq command (INT).

Thank you!
 
Last edited:
I didn't know that the software warned you about exceeding the estimated "packets per second" capacity of an older EtherNet/IP module.

The 1756-ENET is the original 20+ year old Ethernet module for ControlLogix. It didn't even support I/O over Ethernet when it was introduced.

It necessarily has the least capacity of all of the EtherNet/IP modules; it's not even listed in the 1756 ControlLogix Communication Modules technical specifications document ! My recollection is that it can handle only about 900 packets/second of combined I/O and messaging traffic.

For a system with that many adapters, you need a 1756-ENBT or better (1756-EN2T, ideally).

The EtherNet/IP bandwidth estimation tool that's included in the Integrated Architecture Builder is a good tool for determining how you need to adjust RPI's and numbers of devices to suit a control system's network data capacity.
 
Also: you can add more 1756-ENET or -ENBT modules to your controller chassis to get more bandwidth. If all you have is 1756-ENET modules, figure out how you want to allocate your I/O and drives to them, and split up the load among two or more.
 
I didn't know that the software warned you about exceeding the estimated "packets per second" capacity of an older EtherNet/IP module.

The 1756-ENET is the original 20+ year old Ethernet module for ControlLogix. It didn't even support I/O over Ethernet when it was introduced.

It necessarily has the least capacity of all of the EtherNet/IP modules; it's not even listed in the 1756 ControlLogix Communication Modules technical specifications document ! My recollection is that it can handle only about 900 packets/second of combined I/O and messaging traffic.

For a system with that many adapters, you need a 1756-ENBT or better (1756-EN2T, ideally).

The EtherNet/IP bandwidth estimation tool that's included in the Integrated Architecture Builder is a good tool for determining how you need to adjust RPI's and numbers of devices to suit a control system's network data capacity.

Sorry guys, I made a mistake. Looking at the controller organizer from rslogix 5000 it does say 1756-ENET/B, but I typed the IP in my browser and the webpage showed it is actually a 1756-ENBT/A.

Also in the webpage, at the Diagnostic Overview the system resource utilization shows me a 90% usage of the CPU, sometimes even more. The other two ENBT/A that we use are far below the 50% usage.

So it seems that the module is near its limit, right?

Also in the webpage, looking at the I/O connections, I see that the size of the messaging with the drivers is 10 (drivers as source) and 8 (module as source).
 
Just slide another ENBT card next to it or another EN2T and put half of the vfds on that ethernet card in your io config tree.

That diagnostic page gives you connection limits or look in the pdf for that card it will tell you.

Usually 50% utilization is what you want to keep it under. Are you sure you dont have some produced and consume tag that has a real low rpi on it?
 

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