SLC 505 Series C FRN 3-9 Immediately Faults when Connected to Network

huntmthws

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Jan 2021
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I'm a mega noobie when it comes to PLCs and the such. I'm a network guy.

We are currently experiencing an issue where the SLC immediately faults when connected to the main network.

The SLC is forced to half-duplex and the port is experiencing packet collisions (roughly 1000 collisions in the last 5 hours), I have a feeling it's because its set to half-duplex

Attached is a screenshot of the Errors when it is faulted

Screenshot 2021-01-06 215934.png
 
Thanks for providing those details, and welcome to the PLCTalk forum community !

The RA Knowledgebase has a summary of what causes code 16#A2 faults. KB Answer ID BF3067, (Access Level: TechConnect)

The most common, by far, is a duplicate IP address.

But a flood of RARP requests, or a user program that runs out of TCP connections, or even a mis-configuration of a type of "multi hop" MSG instruction in some older firmware can cause that fault.

Unless your SLC-5/05 is connected to a media converter or other device that only supports half-duplex, it should be left set for Auto-Negotiate. The "Series C" hardware added an ordinary 10/100 Auto-MDX port about ten or more years ago.
 
Thanks for providing those details, and welcome to the PLCTalk forum community !

The RA Knowledgebase has a summary of what causes code 16#A2 faults. KB Answer ID BF3067, (Access Level: TechConnect)

The most common, by far, is a duplicate IP address.

But a flood of RARP requests, or a user program that runs out of TCP connections, or even a mis-configuration of a type of "multi hop" MSG instruction in some older firmware can cause that fault.

Unless your SLC-5/05 is connected to a media converter or other device that only supports half-duplex, it should be left set for Auto-Negotiate. The "Series C" hardware added an ordinary 10/100 Auto-MDX port about ten or more years ago.

I appreciate the reply. Duplicate IP was the first concern, but when the SLC is disconnected, the IP cannot be pinged.

As far as Auto-Negotiate goes, the Controls Engineer kept setting it and the downloading the program. Everytime the PLC went online, it was set back to Half Duplex Forced
 
We have an OSI PI Historian on site, could that possible overload the communication to the SLC? Especially since it's quite a bit older?
 
Couple of silly basic questions: the network cable is known good? The switch port is good?

It could be IP addressing problems, or physical media problems. Have you tried forcing the comms to be what you would expect (full duplex, 100M?) and seeing if the controller overrides that?
 
Another remote possibility is that someone plugged a UIC in the Ethernet port, sending voltage into it and damaging it. When an Ethernet cable is now plugged in it shorts out internally.

Had one customer with a similar problem & their maintenance tech said he tried to connect using a UIC not knowing it was Ethernet
 
Another remote possibility is that someone plugged a UIC in the Ethernet port, sending voltage into it and damaging it. When an Ethernet cable is now plugged in it shorts out internally.

Had one customer with a similar problem & their maintenance tech said he tried to connect using a UIC not knowing it was Ethernet


I've always seen this go the other way.


Out of curiosity, do you have any other 5/05's on the site? A spare or one in a machine that doesn't need the ethernet port. Could you swap them and see if the problem moves? This would eliminate the processor.


I've had AB equipment before that wouldn't auto-negotiate, and I had to manually set the switch port to 10 or 100 full-duplex to get the device to negotiate.


Can you plug a laptop into the network cable and see what you get for auto-negotiation?


Those are just some quick-and-dirty suggestions to help isolate the problem.
 

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