Hi
I am using LabVIEW 2012 SP1 programming a TPC-2206 touch-panel computer running Windows Embedded Standard 7.
I have a fairly simple program which uses the LabVIEW "UDP Multicast Open" VI to open a Read-Only multicast port, then reads data continously from it using the "UDP Read" VI.
The routine works by calling the "UDP Multicast Open" VI and if successful, then entering a continous While-loop which reads from the opened port via the opened Connection-ID refnum. If unsuccessful at opening, the routine sits there waiting for the Open to succeed, displaying a message to the user that the network is not plugged in (or similar).
My problem is that if I open the port without a network connection, the open operation succeeds (which is great as its a multicast open and that seems like the right thing it should do), but subsequently when I plug in the network with good data being sent on it, I do not receive anything?! I would have expected data to be received if the port succeeded in opening, no matter what the initial condition of the connection.
When I tried this on Windows XP, I got a open failure which let me know the network was not plugged in. I subsequently programmed it to put up the flashing message and waited for a good connection such that "UDP Multicast Open" then succeeded. Subsequent reception was then good.
Is this a known difference between WES7 and WinXP and LabVIEW "UDP Multicast Open"/"UDP Read", or am I missing something?
Thanks for any help you can give.
