Hello again, What I meant by the synchronization "by hand" was that if one computer has not yet started running and the other computer is writing a request and expecting a response, the whole serial application could just wait forever and not do anything. Anything that a computer receives on its port before it does a VISA Open is going to be ignored by that computer.
It seems that you get around this by sending a "dummy response" if the computer detects no data at its port. >From your description of your program, this should work okay. Assuming you start both programs at the exact same time and assuming that each step takes the same amount of time to run, your first read request will timeout and will return you no data. The 2 computers will then write dummy data to each other, and then the second time through the loop the serial read should pick up the data from the previous dummy response. Is this what you see happening, or is something else going wrong? Depending on what you want to do, you could change one of them to write first. Are you starting both VI's at the same time, or are you running one followed by the other? Which one do you start first? What exactly happens at each step on each computer? Hope this helps. Let me know if you are still having problems, and answer my questions above. Scott B. Applications Engineer National Instruments
