pppn - 2024-06-25

I am facing an issue with my Ethernet-based project in Codesys. My product was functioning well until I modified the protocol stack and uploaded it to my device. Here are the details of my problem:

Project Setup:
I am working on an Ethernet-based project to test my product.
The project was running without issues before modifying the protocol stack.

After modifying the protocol stack and uploading it to my device, I am encountering an error in Codesys related to the forward open connections. Error status: connection failure, extended: connection in use or duplicate forward open.

According to the Ethernet/IP protocol, there are three forward open connections that need to be established.
The first two connections are opening without any issues.
The third connection, which is an input-only connection, is causing problems.
The error message indicates that the connection is already open.

Debugging Attempts:
I have extensively debugged the protocol stack and found no issues.
The product works well when tested with EIP tools but not with Codesys.
Exclusive owner connections are working correctly, and only the input-only connection is problematic.

Wireshark Traces:
Wireshark traces show that the third connection attempts to open but reports that it is already open.

Steps to Reproduce:
Modify the protocol stack and upload it to the device.
Attempt to establish three forward open connections in Codesys.
Observe the error on the third connection (input-only).

I would appreciate any suggestions or guidance on how to resolve this issue. If there are specific settings or configurations in Codesys that I need to check, please let me know. Additionally, if there are known issues or workarounds related to this problem, I would be grateful for the information.

Wireshark traces showing the connection attempts and errors
Screenshots of the error messages in Codesys

codesys version: CODESYS V3.5 SP16 Patch 3 + 64 bit


Last edit: pppn 2024-06-25