NEW_parallel.lbb from LTR 8.4 doesn't work

[pawel]

Hello
In LTR 8.4 NEW_parallel.lbb was issued. The author change it so it should work on LV > 6.0. But I can not make it work.
COM 1 and COM 2 works but LPT 1 works only on the screen, but nothing is changing on the
lines of LPT. Any clues?

thanks in advance

PP

[LucaP.]

Hi Pawel

Have you grounded the BUSY and PE lines? To get the data lines working correctly, ground the BUSY and PE lines. These are pins 11 and 12, respectively. These are both handshaking lines and left unwired, these lines indicate that the printer is busy or out of paper. Grounding these inputs communicates to the parallel port that the device is ready to accept data.

Hope it helps

Luca P.
Application Engineer
National Instruments

[pawel]

Hi Luca,
Yes, I am aware of this and I have it grounded.
regards

Pawel

[LucaP.]

Hi Pawel

I don't know this LTR example. Is it using the Port In/Out VI's? If yes and if you're using Windwos NT/2000/XP you need to install an extra driver (Acesshw.dll). Please check this link. Perhaps you can try one of the described examples too:
http://zone.ni.com/devzone/conceptd.nsf/webmain/72C6FC6CE4AD4D1386256B1800794596?opendocument

Luca P.

[pawel]

Hi Luca
Thank you once more, and I see theat if it was the first my approach to LPT I would have the sufficient help, you give a good advices.
But unfortunatelly I already went through this track and I have Accesshw installed. In fact I have worked with LPT using Port In/Out VI's, but the LTR example I am talking about uses VISA. My old vi works fine, but the reaon why I wanted to change to the VISA driven one is, that the former one has an error handler, whereas the Port In/Out VI's does not.
Normally i do not change something which works for something which does not :), but I have found I need the error handler quite much.
thanks a lot
Pawel

[Randy_H]

Pawel,

I have a few thoughts. I actually built a little printer port LED item to attach to my parallel port to help with support after a VISA e-mail came in. What I actually found was that I needed to wire pins 1-13, 10-16, 11-17, and 12-20. This was the only way to make it work. Now, you probably have an intrument connected on the other side, so some of this may be a littlt different, but when I did this, I could then do a VISA Write to my parallel port.

Then something interesting happened. I tried all four modes on my Dell Optiplex GX150 (AT, PS/2, EPP, ECP) in the bios. The first three worked fine, but if I set the mode to ECP in the bios, it would not work anymore. I have no idea why. I have reproduced this on other machines as well. Then, I tried the s
ame thing out on other brands of computers and got mixed results. For some computers, ECP mode worked fine, but others it did not. I had to come to the conclusion that it was a harware issue that LabVIEW could not control.

Anyway, that is my 2 cents worth on this issue.

Randy Hoskin
Applications Engineer
National Instruments
http://www.ni.com/ask

[pawel]

Hello Randy
Wow, now we are talking :). That's grate you made it work. There is no problem with connecting the given pins. I use
the parallel port to control 256 channel multiplexer which I build by myself, so I can do whatever I want with the pins.
I use pin 2,3,4,5 so all others I have to ply with.
Thank you once more for this help, I shell try this as soon as possible.
kind regards
Pawel