Hi!
What is this "Ex" at the left border of the second line? Exception?
Modbus is able to return error messages.Those contain the original adress and the original function code + 0x80 as well as an error number.
That is, it seems your device indeed speaks ModbusTCP, and responds with a valid error message. At least, it seems so from your screenshot.
Not every software handles error packets correctly, and since nor normal answer package is sent, runs into a timeout.
Click on those lines, and wireshark will show you a very detailed analysis of the packet in the lower half of the window.
It's possible it also shows you the error message as text.
