Control.com - Nerds in Control

Need some help about this issue.

Our plant has an SCADA system using 6 Rockwell Control Logix 5000 PLC and Intouch Wonderware Software in an Ethernet network.

5 Plc's have a quick response when wonderware ask for visualization data (open screens) but one of them has a delay from 30 to 45 seconds to update data on screens.

We already change Ethernet cables and switches without any good results.

I used also a laptop with RSLogix 5000 to try to check PLC configuration and took same amount of time to answer.

Any ideas to resolve this slow response???

Check all the parameters in the ENBT module. There is a diagnostic tab in the "Properties" that can give you some useful information. Also, perhaps try swapping the ENBT with one that is working OK. At least then you will have a better idea of where to look.

Good luck
Cheers

Gerald Beaudoin

Hello,

Try use Wireshark to diagnose the problems with communication.

Regards,
Andrzej
www.modbus.pl

Have a look at System Overhead Timeslice in RSLogix 5000 controller properties. Default setting is generally too low for any significant communications rate combined with busy PLC CPU.

Visit Automated Solutions website to download some PC communications products that will allow you to test ControlLogix command/reply response time alongside your application.

http://automatedsolutions.com/products/dotnet/ascomm/

-Mark
http://automatedsolutions.com

Is this a new application or existing and problem just started to occur? It could be the setup in Wonderware depending on what version and configuration it may not be the PLC controller. You could compare the configuration in your device driver for each of the six controllers.

To Gerald Beaudoin
We already check via browser ENBT Module diagnostic page and we could not find any issue. We will change this module by a new one as soon as we get it from supplier. Thanks for your response.

To Andrzej, I never use Wireshark for control network I will try to figure out how. Thanks Andrzej.

To Mark, I already check this item System Overhead Timeslice and I compared it with others PLC and it is the same in all of them, but I will try to put some higher number, I will inform results. Thanks Mark.

To Scott, our SCADA system has 8 years in operation and during last couple of years PLC time response has been increasing. We are made some minor ladder changes, one or two additional rungs; I think this could not be an issue? Thanks Scott.

We will try to fix this issue, in the meantime we will hear any suggestions, and once again thanks all of you for your ideas.

Regards.
Carlos Soriano

Hi Carlos, Did you fix the slow response issue?

we are just experiencing the same situation with L63 Controllogix 5000. the problem started this week. it was working properly for 5 years. we are also using wonderware intouch.

Thanks

Always remember to click on "Auto negotiate" in settings of ethernet module. Sometimes it might be due to different speed settings on both ends. (like one on 10 and other on 100 MBPS)

Regards,
Dinesh Chauhan
IOC