unable to find visa refnum

[sujani]

I am trying to run several VIs connected to different serial ports-all at the same time.I got the error:1073807246-I was trying to clear it in the way described in this forum-by creating a VI with a 'refnum' wired as input to the VISA close session.I am only able to wire a 'control' to it-and again it shows me some other error(1073807346)-other than this,the VI seems to be perfectly(It is also surprising that I was able to run the same VI without any problems yesterday!Would it be a good idea to 'open' the VISA session just once in the beginning of the whole VI(which has several sub VIs)and then 'close' it only at the end of the whole process?
any suggestions/ideas are welcome.

[Rob Cole]

Opening the VISA session once at the beginning of the program or process and then closing once done, is the usual way to handle it. It saves on a lot of opening and closing. Just pass the reference from VI to VI. This will speed things up a little as well.

Rob