1756-L8 Series Control Logix Fault Bits

Hey All,

I have a 1756-L81E. There is a piece of code I only want enabled when I don't have a communication error present from the ethernet connection. Usually this routes through an EN2T card which I know how to get the fault bits from, however, since on the 81E the Ethernet port is built into the processor, I'm unsure as to how I can access such a bit. Any help would be greatly appreciated so I can see in the code when my connection to the rest of my EIP devices is "healthy".

Thanks!

In the instruction Help for RsLogix 5000 look up the GSV (Get System Value) instruction. That is what we use to monitor the Ethernet comms for CompactLogix controllers with on-board Enet connection. I would imagine that it would work similarly for the larger processor.

Hi everyone,


I've got the very same question, same PLC model L81E and trying to get fault bits specificaly for the Ethernet module, not the CPU itself. GSV with Module / FaultCode is fine for CPU related faults and detecting for example when the module is offline (connection timeout), but there doesn't seem to be anything in the list of fault codes for the built in ethernet port / module.


Regards,
Tom

Welcome to the PLCTalk forum community!

In general, if a thread has been idle for a couple of years, it's best to start a new one. This thread is one of those rare occasions where the clarifying questions had not been answered and the topic hardware was actually the same, so it's really still an open question.

What, exactly, do you want the "fault bits" for the Ethernet port on the 1756-L81E to indicate ?

All ControlLogix Ethernet modules have an Ethernet object and a TCP/IP object, from which you can get things like bad packet counters or the link status.

That data isn't part of the pre-configured GSV Objects, but rather can be accessed using CIP Generic Messaging.

So let's figure out what you want to monitor on that module, and we can search the User Manuals and the Knowledgebase for the details.

Hi Ken,


thanks for the warm welcome!


I'm doing a conversion from L6# processors to the L8# range, but keeping all the old code unchanged (or as close as possible). The old code now running on one L81E has a rung which checks the status of an ethernet module using a GSV /Module / FaultCode instruction and then checks the status of the CPU using the same type of instruction. So I'm trying to modify the rung with the Eth GSV /Module / FaultCode and replace it with an equivalent but for the built-in Ethernet module on the L81E.


So I guess the question should be: how can I replace the original Ethernet module GSV /Module / FaultCode instruction to get the same information from the built-in Ethernet module on the L81E?


Regards,
Tom

Thanks for the details !

I think this is an element of the program you can safely remove.

The connection to the Ethernet module itself is not as relevant as the connections to all of the devices whose connections are routed through the module. If its own connection fails, then all the others will as well.

I don't think there is a Module connection inside the 1756-L8x controller that is comparable to the one between a 1756-L6x and a 1756-ENxx.

Thank you kindly Ken, I was guessing this is going to be the case, but wanted to double check before getting rid of the code.



Regards,
Tom

Hi dscish,

Did you figure out the way to convert L6 to L8 processor successfully?

Riquet said:

Hi dscish,

Did you figure out the way to convert L6 to L8 processor successfully?

Click to expand...

You go to Controller Properties, Change Controller.

There are caveats though. You must have a new enough version of Studio5000 installed which supports the L8 series ControlLogix.

If I'm remembering correctly, the L8 controllers were not all released at once, so which controller you have matters to which minimum version you must have.

Do you have any versions of Studio5000? If so, which ones?

Edit: It may have a better chance at success by converting to L7 first, then L8. I'll try one out....