I am communicating with a serial device on Linux, using LV 7.0 and NI-VISA. About a year and a half ago I had asked customer support if it was possible to change the buffer size for serial communication. At that time I was using NI-VISA 3.0. In my program the VISA function for setting the buffer size would send back an error of 1073676424, and the buffer would always remain at 4096, no matter what value was input into the buffer size control. The answer to this problem was that the error code was just a warning, letting you know that you could not change the buffer size on a Linux machine, and 4096 bytes was the pre-set buffer size (unchangeable). According to the person who was helping me: "The reason that it doesn't work on those platforms (Linux, Solaris, Mac OSX) is that is it simply unavailable in the POSIX serial API that VISA uses on these operating systems."
Now I have upgraded to NI-VISA 3.4 and I am asking the same question. I notice that an error code is no longer sent when I input different values for the buffer size. However, in my program, the bytes returned from the device max out at 4096, no matter what value I input into the buffer size control. So, has VISA changed, and it is now possible to change the buffer size, but I am setting it up wrong? Or, have the error codes changed, but it is still not possible to change the buffer size on a Linux machine with NI-VISA?
Thanks,
Sam
