ControlLogix Message Error

[jrsnydley]

I have a 1756-L62 that is sending a message to give a 1769-L24ER a permissive bit to run. This system has been working fine for about 2 years. Yesterday, I got the following error on the MSG instruction and could not resolve it no matter what I tried.

Error Code: 16#001f
Extended Error Code: 16#0000_0204
Error Text: Error processing connection related service

The L62 was a middle man between the L24ER and an L72 controller. I was able to route the message from the L72 to L24ER in order to give the machine permission to run and get production up and running again. It is working fine and can remain this way.

The question I have is what would cause this seemingly sudden error in the L62? I checked all network cables and connections and I had connection to each device on the network. I tried deleting the rung and the message tag from the L62 and starting over. The MSG is configured exactly the same in the L72 as it was in the L62 so I am not sure what the difference is. Any help to clarify and troubleshoot this issue would be greatly appreciated.

 

[Operaghost]

My first thought is that it is a connection issue on either the L62 or the Compact. But, since the L72 isn't seeing the problem, I think it must be with the L62.

When you open the MSG configuration, is Cache Connections selected? I would look at all MSG instructions in the L62 and see how many there are, and are they caching their connections. And then, do they really need that selected. I typically only use that for auto-repeating MSGs. If it finishes sending and then sends again over and over, that is a good place to cache.

The L7x controllers have twice the available connections of the L6x controllers. So that is what leads me to think your L62 might be bumping up against its connection limit.

OG

 

[Ken Roach]

The error code 0x0204 generally means that the underlying Ethernet link and/or TCP route is broken, and that the message literally cannot get through to the target device. 99 times out of 100, there is a broken switch, cable, connector, router, or other network component.

But "error processing connection related service" does really mean a CIP protocol connection, so a target device that refuses or fails to answer a CIP connection request can also be the culprit. Or, the sending device really can't get an internal resource and the message never makes it out to the backplane or onto the wire.

Because of the troubleshooting history described in this thread, the most likely culprit is the 1756-L62's outgoing CIP connection budget. Power-cycling the controller would have purged that, but it's worth exploring.

But before I did that, I would put effort into verifying the ordinary Ethernet and TCP connectivity between the L62 and the L24. A lot of us do that by visual inspection of cables and link lights, which is useful but not as thorough as using PING, then TCPING/TNC to check to be sure that TCP Port 44818 is open and accessible on the target device.

 

[jrsnydley]

Thank you both for the information. The L62 does have quite a few read/write messages. I will look into your suggestions and see what I can figure out.

 

[mylespetro]

Thank you both for the information. The L62 does have quite a few read/write messages. I will look into your suggestions and see what I can figure out.

I've also used Rockwell's suggested message staggering protocol to control the execution of messages in sequential order with great success.