TCP write doesn't work in Veristand 2017

[raphael.wittwer]

Dear Forum

I am trying to send a telnet command to some custom hardware, unfortunately there is no data being sent. The task would be quite simple and it works both from Windows 7 and a simple real time project running on the target without Veristand, but not from the custom device in Veristand itself.

Looking at the traffic with wireshark I can see that the TCP write does not send anything to the target, but the code doesn't produce an error either..

I could share the code for both the real time target and the custom device, however I don't know if this is the source of the problem at all. Is there a problem with TCP write in Veristand 2017?

Thanks in advance,

Raphael

[Eric.M]

Before looking into Wireshark (that stuff is for heavy debugging!), I would check whether the TCP Open is able to return anything (without error). It allocates the socket and configures it, so there should be packets being sent/received at that point already.

And no, I can tell there's no problem with TCP 🙂

[raphael.wittwer]

Hi Eric

TCP open does not produce an error, it also doesn't send any packets.

I have a SOAP interface running on Veristand as well, in theory this would show that TCP works when used through the http.put block. Still TCP write does not send anything.

Thanks, Raphael

[raphael.wittwer · Accepted solution]

Hi all

the problem was as simple as it is embarrassing: There was no connection in the VI start to hand through the reference to the TCP write.

Why the TCP write does not return an error with the empty reference it is getting is still not quite clear but at least it works with the reference..

Thanks to NI for finding this!

Raphael