Problems in VISA communications with Labview8.20

[GcDago]

Hi,

I’ve just upgraded my software from Labview7.0 to Labview8.20 and I’m having some problems with the VISA communication. In particular I’m sending commands and receiving data via serial port. The port is working correctly only if a strange symbol is present on the block diagram when you select COM1, COM2 etc in the port setting. If the symbol is absent the communication doesn’t work. I have the feeling that it is something related to the busy or free of the port but I’m not able to go on, how can I solve it?

The software works without problems with Labview7.0!

Thanks a lot

Giancarlo

[Dennis_Knutson]

Can you post an image of this 'strange symbol'?

[GcDago]

I'm sending a stamp of the block diagram.

thank you for your help.

Gcdago

[Dennis_Knutson]

See the post at http://forums.ni.com/ni/board/message?board.id=170&message.id=212658&query.id=53336#M212658.

Are you doing a VISA Open before you try to do a Read or Write?

[GcDago]

Dear Dennis,

I think that I didn't do the VISA open before doing the VISA write/read. I'm going to add it tomorrow morning.

Moreover, should I doing the VISA open also before setting the serial port?

Thank you in advance

GcDago

[Loura]

Hi Gcdago,

for comunication with serial port you don't need to open Visa session with 'VISA Open' if you set the serial port with 'VISA Configure Serial Port'. Remember to close the VISA session at the end in order to free the resource. For an example of a tipical serial comunication with LabView refer to Basic Serial Write and Read.vi in LabView examples.

Have a nice day.

Clara

[GcDago]

Thank you foir the information concerning the VISA open. I'm doing the VISA close after the VISA session but the problems are still present.

Now I'm waiting for the help next tuesday from the National Instrument support who told me that the problem could be due to BIOS settings...but I'm completely ignorant in this fiel...

I'll keep you informed,

GC