daq-assistent not working sometimes

[mh_51]

Hi,

I'm new to LabView and I experience a strange problem: The DAQ-Assistent stops working correctly some times. It is running correctly till all configuration is finished and the sub-vi should be created. After that I have this sub-vi but with no input or output connections, just the symbol of the vi. By double clicking it, the configuration is running normal, but after clicking OK there is still no in- or output by the vi.

My steps are:

1. open a new vi in labview

2. clicking the express --> input --> DAQ-Assistent  

3. configuring by my means (analog input, voltage, channel ai0)

4. testing the input (all is working)

5. clicking OK, so the vi is created

I had this problem before and solved it by reinstall (repair the installation) labview and DAQmx. After that it worked. But I haven't  made any changes to the computer since the last time it worked and now, after the weekend, it isn't possible to create a running vi again. I can use my old vi which I saved, but it isn't possible to alter the configuration made by the DAQ-Assistent. I don't know how this is possible or how to solve it, so I hope you can help me. I can provide some picture with my steps and showing that the hardware is running (as I see some output in the MAX testpanels as well as in the DAQ-Assistent) and only getting a vi with no connections and my saved vi where it is still running as long as I don't change anything by the DAQ-Assistent.

Thanks for any advice. 

Hardware:

PCIe-6251

BNC 2110

cable: SHC68-68-EPM

Software (german):

Windows XP SP3

LabView 8.6

DAQmx 8.9

MAX 4.5.0f0 

EDIT:

Now after waiting and trying it several times, it works again. I can't explain it . Even after several reboots and starting and closing the program it wasn't working and now all of a sudden it's OK... I welcome any explanation, why this happens from time to time...

Message Edited by mh_51 on 05-11-2009 07:54 AM

[Marian_O]

Hello MH_51,

thank you for posting at our forum. This behaviour sounds abnormal to me, but I need some more information to clarify the problem:

What do you mean with step 4. "testing the input". Are you hitting the "run" button inside the DAQ Assistant?

Could you post one of these "damaged" Express VIs without any inputs / outputs?

Best regards

[mh_51]

Hi MarianMO,

thank you for answering.

Yes, by testing the input, I meant hitting the run button. I try adding some picture to this post to illustrate my steps as well as adding a saved vi with a non-working DAQ-Assistent.

pictures hosted at imageshack.us 

step2.jpg

step3.jpg

step4.jpg

step5.jpg

vi hosted at rapidshare (only 10 downloads possible, if it is needed more ofte, I will put it on an other hoster)

non_working_daq.vi.html

I hope these files will illustrate my problem.  By the way, if I'm trying to reconfigure my settings in the DAQ-Assistent in a working vi it happens (if it is not working) that LabView shows errors about non existing and/or wrong input types, because then there is (as said) no in- or output.

Kind regards,

mh 

[Marian_O]

Hello MH,

thanks for your upload. Did the attachement - function of our forum not work? If you enter a new post, you have the possibility to add an attachment. It is a link below the text box.

What OS are you using? Linux or Windows? I took a closer look to your VI and found something very strange. Could you try to deinstall your RAR - Ziptool? It seems to me, that there is an incompatibility.

Best regards from Munich

[mh_51]

Hello MarianMO,

the OS running LabView is a fully patched Windows Xp with ServicePack3. To be totally correct I should say, that I'm using the computer per RemoteDesktop from a Linux machine, but that shouldn't disturb any program, should it?

I have installed 7zip for (de-)compressing files which is able to handle rar and other formats, too. I can't imagine how this can influence LabView, because LabView should run without a packager, too. Or is it using the packager it finds on the system? I don't know. And what kind of incompatibility can this be? I'll try to uninstall 7zip and see if the behavior still appears.

 As for the uploads, I think I saw a file attachment link at starting a new thread, but now by replying to a topic I see only the Submit/Cancel Post buttons and the Tags box under my text box. Or am I supposed to edit the first post to add files? The images were links because I thought it is better to have them as links so the images won't take a lot of space in the post (reduce scrolling) and one can decide to look at them or not. It differs from message board to message board what is the most liked form to do it.

 I'll inform you if uninstalling changes anything in the behavior (perhaps a get to it today, else I will do it tomorrow).

Kind regards,

mh (sitting in Erlangen) 

[Marian_O]

Ok, what I found out: there is a possibility to convert the Express-VI to LabVIEW-Code. Right-Click on the item and select: "open front panel". If you open the frontpanel and swich to the blockdiagramm, you will usually see the DAQmx code.

In your case, I only see textlabels with something related to rarlab:

 

It seems to me, that when creating the automatic code for your express VI (after hitting OK), the scripting does not succesfully reference to LabVIEW  but to RAR lab. Could you verify this by uninstalling it?

[mh_51]

I followed you instruction by opening the front panel of the DAQmx vi and I was left with the two pictures below. One is from a working vi (left or upper), the other is not (right or lower). One can see the data connection on the working vi as well the non-existing connections on the non-working vi:

 

 I also have uninstalled 7zip but that had no effect in the behavior of labview. By the way, I had never installed winrar and in the registry there is no entry with winrar or rarlab. Perhaps it comes from your side?

I'll try to phone the support of NI later the day, perhaps they have heard about this and can help me. Thanks for your help so far and I still welcome any ideas.

Kind regards,

mh

EDIT: changed picture position in text for the case they're on top of each other or side by side. (By the way, the add attachment link is back for me; still strange)

Message Edited by mh_51 on 05-13-2009 05:54 AM

[Marian_O]

Hello MH,

thank you for your detailed Screenshots, one important screenshot is missing: if you open the front panel from the corrupt express-VI, please switch to the coresponding blockdiagramm and post this picture here, too

Best regards

[mh_51]

Hi MarianMO,

I think, I have found the reason with your help. I just tried to create another express vi with the DAQ-Assistent. I converted it and open all the front panels and block diagrams. What I saw were some part my last post here. OK, now here is the reason:

I wrote some times before, that I'm using Remote Dekstop to control the measuring (win XP) computer. I'm doing this from a linux machine where I work (and write this post). Some times before I wrote my last post here and have recently tried the steps again you proposed. The frontpanel of the non-working DAQ vi came up with parts of my last post. And this was the content of my clipboard!! The linked vi some post above had old clipboard contents where I installed unrar on another machine. If I delete my clipboard contents all works well. This behavior is reproduceable now.

Now is the question if this is a bug in LabView or the Remote Desktop client or both?

So I wish you a nice afternoon.

Kind regards,

mh 

[Marian_O]

Hi MH,

is there a way to empty the clipboard in Linux? I am not that familiar with this OS. In Windows, you can try to copy a blank text, but there is no explizit function to clear the clipboard.

The behaviour, you mentioned, sounds really interesting. I would like to reproduce it. Without using a remote desktop, the phenom does not appear. Could you give me more information about the remote software, you are using?

Best regards