Control Logix Controller Failure

[stuhad]

We have recently experienced two failures on our Allen Bradley Controllogix PLCs and I have been tasked with researching the problem and hopefully finding a solution. One of the PLCs is a 1756-L55 Controllogix Controller Rev 13.25 & the other is 1756-L55 Controllogix Controller Rev 11.25

On both occasions the PLCs have been online with our programming Laptop, and on both occasions the laptop has frozen while we have been looking through the Logic then the system has tripped.

On each occasion we have had no PLC fault lights illuminated and when we removed the laptop the faults have not reoccurred.

On each occasion there has been a background communications program called Notifier Gateway running. Is it possible that this may have interfered with the communications between the Laptop and the PLC causing the problem ? We have since been on line with our laptop with all background communications programs shutdown and not experienced the fault again.

Are there any hotfixes or updates we need to prevent this from happening again?

 

[geniusintraining]

Do you have anymore information ? such as the OS on PC and the version of RSLinx running

 

[stuhad]

The laptop is running Windows XP. Not sure about the software versions

 

[harryting]

When you say the system "tripped", what exactly does it mean? Did you have to clear the fault? Did all digital output turned off?

 

[dginbuffalo]

Is your laptop connected through Ethernet? Could you have duplicate IP addresses or a conflict?

 

[stuhad]

The system under control tripped then we were able to restart immediately. The laptop was connected via the rs232 link

 

[harryting]

A programmed trip? A system trip can mean so many different things it doesn't necessarily means the PLC malfunctioned, which seems to be your conclusion but only thing for certain from the facts you provided is that the RSLogix program locked up.

 

[JonHopper]

This post is very confusing..

Have the controllers failed? Or faulted? You say you were able to immediately "reset"... Whatever that means.

Are you inquiring as to why the laptops have froze? Or are you actually having some kind of issue with the PLC ????

 

[stuhad]

Hi

This happened at the same time as the laptop froze the PLC Failed. This caused the system the PLC was controlling to shutdown

 

[Ken Roach]

To troubleshoot this system using community input, you're going to have to be very explicit and detailed in explaining what you mean by "tripped" and "restarted".

I've never heard of a ControlLogix that faulted without showing a Fault LED, but I also don't know if you're checking the controller before or after the system has restarted.

Can you tell us exactly what steps you go through to restart the system ? Do you power cycle anything ?

If the laptop "freezes", how is functionality restored to it ?