Socket UDP Send not working in NJ Series / Sysmac Studio Posted 7 Apr 2018 · Edited 7 Apr 2018 by Lacita 5 hours ago, innoaloe said: I think I'm starting to get what's happening... but you need to try it. Delete all of the Initial Values set for your Socket variable. In the SktUDPCreate documentation it describes that both SrcAdr and DstAdr sections will be filled with zero once the socket is created. As UDP is an unconnected communication, you don't need to specify any source IP Address. If the UDPCreate is successful, fill the DstAdr with your target device IPAddress and PortNumber, then try the UDPSend command. The Handle value is basically just a pointer. If you Create a socket one time in the entire program, it will be filled with 1. If you create another socket, it will have 2 as the handle value. If say socket 1 is closed properly, next time you open a socket it will get 1 as the handle value. So it's predetermined by the CPU. Oh wow thank you very much innoaloe, it works!!! This is my setup, hope it will help for anyone have to face this problem.