CIP communication fails after firmware upgrade

[WimVriend]

My colleague has upgraded the firmware of our 1756-L85E CPU from v33 to v35. After doing this, the CIP-client is unable to connect to the PLC, so no data can be read (pool.aquire fails).

It is however possible to retrieve the firmware version of the CPU, using the GetAttributeListService.

Could this be related to the implementation of the CIP client, or can it be some issue related to licensing or something like that?

[kevinherron]

What's the error message / code? Do you have a capture you can share?

[WimVriend]

@kevinherron : I sent you an e-mail, containing two Wireshark captures. Any help is greatly appreciated ...

[kevinherron]

@WimVriend does it work with v35 if you use an "empty" connection path like this instead?

var connectionPath = new PaddedEPath(List.of());

[Marc-Dierikx]

As the mentioned colleague of Wim, I can confirm that with that setting the connection succeeds. Tags addressed in the same manner as with the 33 version firmware are not recognized though.

[kevinherron]

@Marc-Dierikx I noticed in the Wireshark captures that you are not configuring a vendor ID, which results in the ForwardOpen request using 0 for originator vendor ID. This is the only difference I can see when compared to the Kepware capture, which sets the vendor ID to the one assigned to their org.

Can you try setting a non-zero vendor ID and see if that changes anything?

[Marc-Dierikx]

That does the trick. Thanks!

[kevinherron]

That explains why we've never seen this issue in our usage and weren't able to reproduce.

[WimVriend]

At this moment I don't have the exact message, since my colleague did not save it and now he has downgraded the CPU to v34 (which does work, so both v33 and v34 work, only v35 does not).

I will have to ask him if he wants to go through the motions again next week ;)