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S7NetPlus / s7netplus

S7.NET+ -- A .NET library to connect to Siemens Step7 devices
MIT License
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S7.Net.TPKTInvalidException: TPKT is incomplete / invalid #411

Open kaustas opened 2 years ago

kaustas commented 2 years ago

Hello. I'm facing an issue with connection to PLC.

There are two PLCs (S7-300) to connect with one application. Problem happens when the second instance of application is started: one of PLCs failed to connect with TPKT is incomplete / invalid error message. At the same time second PLC connects without problem. Doesn't matter at what PC application's copy starts on same or different.

I thought there could be some limit for connections amount, but I didnt find any information about 102 port limitations and ISO on TCP. image

I have no idea why this happens.

scamille commented 2 years ago

Do I understand this correctly: You have a application which connects to both PLCs. The first instance of your application works fine with both PLCs. Once you start a second instance of your application, only one of the two PLCs works in this second application instance. And I presume the first application instance works fine the whole time.

Is that correct?

kaustas commented 2 years ago

Yes you understood this correctly.

scamille commented 2 years ago

Ok. I don't know much about connection limits for S7 plcs, but I would assume that there is something restricting the number of connections on your second plc, at least more tightly compare to the other one.

S7NetPlus currently does not fully parse all error codes in the responses it gets, so the TPKT is incomplete / invalid message might in fact contain something stating explicitly that some limit has been reached.

rafasimple commented 2 years ago

Hi i have the same problem, the TPKT is incomplete, , but i dont know why, whit CPU 317 with CP343-1 Siemens,the error appears usually and then dissapears.

umha commented 2 years ago

I also encountered the same error in the simulation environment. I tried two kinds of CPUs, 1200 and 1500.

Alkaidxx commented 2 years ago

when i use the CP243-1 to connect s7-200 with s7.net(use plc.open) , this problem(the TPKT is incomplete) is also appened. has anyone solved it?

sebastianhofer commented 5 months ago

Is there any update on this issue? I have the same problem with S7-300 CPU, with the latest S7.Net Version 0.20.0.

Alkaidxx commented 5 months ago

Is there any update on this issue? I have the same problem with S7-300 CPU, with the latest S7.Net Version 0.20.0.

You can try earlier Version

sebastianhofer commented 5 months ago

You can try earlier Version

We fixed it with restart of the CPU (STOP -> RUN). After that the same lines of code works fine.

superbug8848 commented 4 months ago

I have same problem , CPU is S7 416， when my program want to connect to PLC, get a exception with “TPKT is incomplete / invalid ”， I use S7.net 0.20.0