I upgraded my VISA to 2.6, which seems to work fine with Labview 5.1 (I couldn't find version 2.5 for Windows).
I still have the same problem. If I use serial VISA, I can get well-timed pulses at up to 62kHz out of the parallel port, connecting it as given in the <a href="http://zone.ni.com/devzone/conceptd.nsf/webmain/72C6FC6CE4AD4D1386256B1800794596?opendocument&node=DZ52058_US";>Using the Parallel Port in LabVIEW</a> tutorial and using their vi. NI-Spy shows that the commands are sent as they are generated, but the pulses do not actually go out the port until after the VISA session closes. I have tried flushing the buffer after every write. As a result, I can get the requested pulses, but with no feedback as to when they are complete. If I open VISA, write a number of steps to VISA, then close again, I get a 50ms gap between segments that I write. I want the output to appear seamless. In the past I have used the outport.vi, but to get evenly-spaced steps, I have to use the wait-ms.vi This limits my pulse frequency to 500 Hz. To go faster, I have used a for loop with several hundred iterations -- this leaves an erratic pulse train and is difficult to control and ties up the processor. 500 steps/second is also too slow when you consider that a typical scan requires 120,000 steps, each direction. So if anyone knows how I can get a regular pulse train out of the parallel port (or is their another port that would work -- not the serial though) and know when it completes so I can continue my program, I would appreciate some help. Thanks, Scot
