inport and outport vi of labview 6.1 on win xp

[msrit]

hi,

i wrote a simple program to write and read from the data reg of parallel port using the outport and inport vi's of the accesshw library.it runs without giving me any errors.but does not show be the value i have written either.i am attaching the program.let me know if you can find something wrong with the program.thanks!

write-read1.vi (16 kb)

[smercurio_fc]

Problem 1: You did not include the subVIs.
Problem 2: Problem 1 is irrelevant, since you have none of your objects wired up!


You should look at the parallel port example that ships with LabVIEW on using the InPort and OutPort VIs.

Message Edited by smercurio_fc on 02-26-2007 08:53 AM

[msrit]

hi,

     thanks for the reply.but i am still unclear about what you meant.which objects are not wired up? i ran a c program to write to and read from the port and there was no problem.i would appreciate it if you make the changes in the program that i have attached.thanks a lot.

[msrit]

hi,

    i am using labview version 6.1 .i did not find any inport and outport vi examples.

[smercurio_fc]

Hmmm.. That's one of the weirdest things I've seen. When I first opened your VI I got icons with the big question mark in them indicating the subVI couldn't be found, and there were no wires connecting the constants to the VIs. I just tried opening it again based on your recent post, and now the subVIs show up, and the wires as well! Very strange.

You would need to search for "parallel" to look for parallel port examples. Unfortunately, I don't have LabVIEW 6.1, and it that version's InPort and OutPort functions are different than the ones that come with later versions of LabVIEW.

Also, when you say it doesn't show you the value written, are you referring to the InPort VI's output, or are you actually looking at the parallel port line states?

You may find the following of some use:

http://forums.ni.com/ni/board/message?board.id=170&message.id=47992&requireLogin=False
http://forums.ni.com/ni/board/message?board.id=170&message.id=149029&requireLogin=False
http://forums.ni.com/ni/board/message?board.id=170&message.id=33494&requireLogin=False

[msrit]

hi,

      as an answer to your question....i was referring to the inport vi's output and not to the voltages available at the lines.

[smercurio_fc]

OK, but have you verified if the actual lines are changing on the parallel port? Like with a DMM?

[msrit]

hi,

i measured the voltage at the pins.Irrespective of the the byte i write to the port,the voltage at the pins is 0.6V which corresponds to a logic zero.i  am using ecp/epp mode of the parallel port which should support bidirectional mode.i am at a complete loss as to why this is not working.any help is appreciated.i have searched the discussion forum for similar posts and found a few but i am not really able to find any solution for this problem.

[smercurio_fc]

You should follow up with the information given in this thread. I believe the document that's referred to in that thread is this one. The basic problem is that the InPort and OutPort functions that shipped with LabVIEW 6.1 don't support XP. The ones with 7.1 do. The library provided in the document to which I provided the link is supposed to provide versions that you can use in 6.1.