VISA Parallel Port Error

[NickO]

I am trying to access the PC Parallel port using MAX and the Instrument I/O Assistant express VI (hoping the work has been done for me!). I see a ! on LPT1 in MAX with the message:

VISA returned this static device when finding resources, and MAX could use VISA to parse the resource name.  MAX could not succesfully open a VISA session to the device.

How can I make MAX and the express VI communcate with the parallel port?

Thanks

Nick Owens

[MarkLe]

Hi Nick,

Thanks for your post. If MAX isn't able to get a VISA session to the parallel port, then you won't be able to in LabVIEW either.

A few things could be going on here, one problem could be that another application has access to the parallel port and is stopping VISA having access to it. So check that no other application is trying to write to the port at the same time (this includes printers that are set up to communicate through the LPT).

Secondly, you could have some issues or wrong settings for the port in BIOS, there is a KB here which may help you:

http://digital.ni.com/public.nsf/websearch/31DC65938A666A9A86256F56005B2624?OpenDocument

This will take you through checking the BIOS settings, then confirming the port is working in Windows, before you try MAX.

Finally, I would try checking you have NI VISA properly installed, there are some notes about how to check this here:

http://digital.ni.com/public.nsf/websearch/928D3D3B63AF0EF186256F12004D7E12?OpenDocument

If you suspect VISA could have been installed wrongly, or may be corrupt you can try reinstalling or repairing it, from the Control Panel - Add or Remove software option.

I hope this helps, if you get rid of the ! by the port, try writing to it in MAX using the VISA test panel and Basic IO tabs.

Please let me know how you get on, or if you are still having problems.

Mark

Applications Engineer

National Instruments

[NickO]

I have lost the !. What seemed to work was the LPT properties: 'Use any interrupt assigned to this port', and IRQ7 appeared. There was a reboot and reinstall inbetween and it seemed to need this configuring again, but I can now go back and try communicating!

Many thanks

Nick Owens

[MarkLe]

Hey Nick,

Thanks for the update, glad the LPT port is working OK now!!! I had similar issues with a soundcard conflicting with BIOS settings over the weekend, really frustrating at the time, but great when you fix it!

Good Luck with the rest of your project.

Mark

[NickO]

I am now as far as dealing with the equipment's intransigence; once I've worked out a command string that it OUGHT to reply to, I shall then know which lump to hit!

Thanks

Nick