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Channel Writers/Readers just disappear. No error messages or anything.

Does anyone know what could be generating this issue?

 

I don't get any error messages.

 

Restarting the PC and LabVIEW doesn't help.

I've made sure the LabVIEW Data folder is in the correct location. (in Documents, locally)

 

What's weird is sometimes it works, without changing anything. So I have no idea what's different or why it worked in those cases. But I have to try that many, many times. Its completely random as far as I can tell. (I attached a gif of the issue)

 

Any advice? What else should I try?

 

I'm using LabVIEW 2017, 17.0f2 32-bit.

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Message 1 of 17
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I think I started using channel wires with LV2018, and have used them a lot now, but I have never seen this.

 

Try and delete the extravilib-folder when LabVIEW is closed and start LabVIEW again. It's in the documents folder for the user, then in LabVIEW Data\2017(32-bit)\.

 

If it doesn't work, maybe try a fresh install, if you cannot upgrade.

Certified LabVIEW Architect
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Don't know about this issue specifically, but I'm assuming that what you're seeing is the scripting code running and then rolling back the undo transaction, probably because of an error.

 

One thing you could try to do is to see if you can look at the channel creation code and see where that could happen. I'm guessing the code is unlocked and is probably in <LabVIEW>\Resource somewhere. There are probably one or more threads discussing where it is in the relevant user group.

 

I'm not sure if you would be able to set breakpoints or conditional breakpoints on it, because it probably runs in its own context, but maybe you could at least modify it to write stuff to a log file. Of course, you would probably want to keep a copy of the original code before you start making modifications.


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Message 3 of 17
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You probably can set breakpoints but have to restart LabVIEW after.

Certified LabVIEW Architect
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I tried deleting the extravilib folder, but that didn't solve the issue.

 

I definitely wanted to avoid having to do a fresh install. I hadn't thought of looking into the source code and seeing what's causing those issues. I'll try that next.

 

If that doesn't work, fresh install it is.

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Ps: I'm looking for those resources, but If anyone knows where those libs/creation code scripts are, please chime in.

 

Edit: Nevermind. Just found them. They're quite literally inside the resources folder.

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Alright. So the endpoint creation VI is working. It seems that the issue is occurring around UpdateChannelEndpoint_ExecCore.vi

 

. . . It's password protected. I don't suppose there's any way of debugging that now is there.

 

: /

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Thank you for the very clear (not) explanation of your problem and precisely what you were trying to do.

 

Frankly, a .gif (with no documentation or text) is a pretty poor way to aid us in trying to understand or replicate your issue.  Please forgive me if I miss an obvious step in what follows:

 

I opened LabVIEW 2017.0.1f3 (32-bit).  I opened a blank VI.  I put an empty String, gave it the label Message, right-clicked it, and tried to create a Messenger Channel Writer with Abort.  After a few seconds, it appeared and connected up with the blank string.  I don't see any problem.

 

I've been using Channel Wires, especially Messenger Channels, ever since (before) they were introduced in LabVIEW 2016.  I have one routine with close to 100 Messenger Channels running at the same time (actually, I'm not sure I've ever run the 100-channel version, but have certainly run >50).  I have not needed to run the Messenger with Abort as I try to avoid "Abort" situations.

 

If you have further information that can help me to reproduce your situation (like, perhaps, existing code in the context of which this error occurs), please attach such information, and be sure to attach VIs and supporting material as native LabVIEW entities, not pictures or movies, which do not provide LabVIEW-specific information useable for testing purposes.

 

Bob Schor

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Message 8 of 17
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@Bob_Schor wrote:

Thank you for the very clear (not) explanation of your problem and precisely what you were trying to do.

 

Frankly, a .gif (with no documentation or text) is a pretty poor way to aid us in trying to understand or replicate your issue.  Please forgive me if I miss an obvious step in what follows:

 

I opened LabVIEW 2017.0.1f3 (32-bit).  I opened a blank VI.  I put an empty String, gave it the label Message, right-clicked it, and tried to create a Messenger Channel Writer with Abort.  After a few seconds, it appeared and connected up with the blank string.  I don't see any problem.

 

I've been using Channel Wires, especially Messenger Channels, ever since (before) they were introduced in LabVIEW 2016.  I have one routine with close to 100 Messenger Channels running at the same time (actually, I'm not sure I've ever run the 100-channel version, but have certainly run >50).  I have not needed to run the Messenger with Abort as I try to avoid "Abort" situations.

 

If you have further information that can help me to reproduce your situation (like, perhaps, existing code in the context of which this error occurs), please attach such information, and be sure to attach VIs and supporting material as native LabVIEW entities, not pictures or movies, which do not provide LabVIEW-specific information useable for testing purposes.

 

Bob Schor


No need for the passive aggressiveness.

 

I sincerely thought it was pretty clear from the .gif and the post in my opinion. I mean I could be biased. I'll take that into account in future posts.

 

The main issue: 

  • "Channel Writers/Readers just disappear. No error messages or anything" <- Exactly what it sounds like. I attempt to create channel writers and the operation just doesn't work. That's it. Just like in the gif, I can create a channel writer and then it disappears. No error messages or anything. Am I misunderstanding its operation...?

Some facts about the issue:

  • The VI at moment of creation doesn't seem to matter. I can replicate this issue with any VI, be it in a project, library, stand-alone, etc.
  • The channel writer or reader creation fails ( I assume ) for any type of data. I can't create any kind of channel writer. This means, the type of data source and the type of channel I'm creating does not matter. (From my point of view) Since it doesn't seem to work with anything.
  • Sometimes, it works. Like I explained, if I keep trying and trying sometimes, it works. From my point of view it seems to be completely random. For example: Today I tried to create the channel writers about 35 times-ish. I could not get it to work. Yesterday I managed to get it to work twice, in a seemingly random way.
  • The channel is created. Once the VI that creates the channel goes out of memory, the channel disappears (From the block diagram). (UpdateChannelEndpoint_ExecCore.vi) <- As far as I can tell, there's no errors, but I can't inspect any further.

I'm not following you when you say native LabVIEW entities, you mean like the lib in charge of creating channels?

 

I'm not misunderstanding channel creation right? I mean I've used them in other contexts before.

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Bob, I'm going to go ahead and disagree here and say that a gif is actually pretty good as far as showing the issue and precisely what he was trying to do.

 

As far as replicating the issue, it's with near-certainty a problem with his specific computer at this moment and not a problem with LabVIEW 2017 or channel wires in general.

 

To the original poster:  Do you have a license in good standing including NI support?  It couldn't hurt to ask.  They are after all the people who have the password to the VI that might be able to give you a hint at what's wrong with your setup.

 

Since this may be trying to write something to disk, could you try it either with your antivirus disabled or by running LabVIEW as administrator just in case there's a weird issue there?

 

Is this something where you could take the nuclear option if need be?  Complete uninstall and reinstall?

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