Hi. I have the following setup. One computer has DAQ boards in it and is situated in a remote underground location. The second computer, in the lab., has no direct acces to DAQ hardware. The two computers are link in peer to peer configuration and communicate through TCP/IP. Applications are written in LabVIEW (ver. 5.0, Full development edition). Since once the DAQ computer was operated locally there are lots of applications written that work very well. One easy way to adapte them to the new setup consist in replacing all direct calls to VI's that acces the hardware with VI's that use Invoke Node to call simple VI's on the remote computer that will acces the DAQ hardware. As an example lets imagin
e that in a application a VI that acces a PCI 1200 board is replace with a VI that uses 3 Invoke Nodes, first one to set a value (channel(s) to be read), the second to start the remote VI and the last one to read the result (double or array of doubles). I timed the remote VI that acces the hardware : 14 ms. Than the VI that uses Invoke Nodes : 1300 ms. This is unexpected since Open Application Reference and Open VI Reference were called well before the VI containing the Invoke Nodes starts to execute. IP number addressing is used to avoid any possible name resolution conflict. In VI server configuration I uncheck "strict checking" option. Ping time between the two computers is 1 ms. Than I downloaded an example VI from the NI web page. This VI uses one Invoke Node to read the value of a global variable on a remote PC. Execution time is about 550 ms.
What is the expected execution time (order of magnitude) for the Invoke Node once a VI reference number is provided? In other words how
long a Invoke Node takes to read (or set) a value (one double) on a remote computer?
