LabWindows/CVI has received an invalid reply to a debugging message.

[cholulteca]

We have just installed LabWindows/CVI 8.5.0 to work with a RealTime-PXI-System (PXI-8196). Compiling and running a program on the host PC works fine, but whenever we try to load a dll to the realtime machine, the following error message appears: "LabWindows/CVI has received an invalid reply to a debugging message."

Transfering a vi to the real time machine using LabView works fine, as well as accessing the machine via MAX.

Any ideas what is going wrong?

[JonathanN]

Hi cholulteca,

Are you also using the LabWindows/CVI Real-Time Module? Since we came out with a CVI version of the Real-Time module, you are no longer required to use LabVIEW to download your CVI RT dlls to the RT target. You can download and debug all from within the CVI IDE. 

When you say "whenever we try to load a dll", how are you getting that DLL onto the target? If your not using CVI RT, then I'm a little confused. I was thinking you might be using the LabWindows/CVI Real-Time File Copy Utility but if you don't have CVI RT, then that doesn't make sense.

Before I ask any more questions, can you please clarify what products you are using and versions?

Thanks

Best Regards,

[cholulteca]

Yes, we are using the CVI RT-Module. We don't manually load the dll to the target, but when debugging the project, by clicking the "run" button it is usually downloaded automatically (and this is when the error message appears). We do not use any file copy utility.

We just don't understand why we can access the RT system via MAX and via LabView, but not via CVI. We haven't actually tried to download the dll manually, because for the normal workflow, this isn't really an option for us.

[JonathanN]

Hi cholulteca,

We did fix an issue in the CVI 8.5 RT module where that message was thrown when debugging an RT application from a host computer with more than one physical and/or virtual network adapters. However, since you are using 8.5, that rules out that possible issue. So questions I have for you include:

- Did this issue just start happening recently?
- Could you ever download this specific project which creates a DLL to the RT target?
- Can you build and download any DLLs from examples CVI projects?
- What about creating a basic RT DLL and downloading that?
- Could you post a screenshot of what SW you have installed on the RT target? Just paste an image of the LabVIEW Real-Time Software Utility dialog found in MAX.
- Did you have prior versions of the RT module installed? If so, did those work?
- Do multiple machines exhibit this behavior?

Best Regards,

[cholulteca]

Ok, well let's start then 😉

This issue has been happening since we installed the whole 8.5 package
Before, we used version 8.1, and we never had any problems downloading dlls.

We cannot download any example projects nor the most simple program.

I'll post a screenshot on monday, I'm not at work right now.

Two different machines show this behavior, both machines have the same software installed.

Thanks in advance for your help!

[JonathanN]

Hi cholulteca,

Just so I am clear, you receive the error with our example projects as well as with very simple programs? And this error occurs every single time you try to debug the DLL (i.e. every time CVI tries to download the DLL)? Also, does the error immediately pop-up or is there some delay after downloading the DLL?

Best Regards,

[cholulteca]

Yes, we get that error message with any project.

The error pops up immediately, right after choosing the RT target (even before clicking the "run" button), or, if the target had been chosen, right after clicking "run".

[JonathanN]

Hi cholulteca,

The behavior you are seeing kinda describes the scenario of a bad CVI RTE installation on the RT target. To test this theory out, can you try using the LabWindows/CVI Real-Time File Copy Utility? I am expecting you to see the same error.  You can use this utility from within CVI by selecting Run » Switch Execution Target » Select Target with Options.  In this dialog box, select the RT target from the ring control at the top of the dialog box and click Copy Support Files to launch the utility. Then try and download some support files. This utility will attemp to connect to the CVI RTE on the RT target and it if can't, then the error should be thrown.

Also, I wanted to clarify you statement of "two different machines are showing this behavior"? I assume you were talking about two different host machines which are both talking to the 1 RT target?

Best Regards,

[cholulteca]

Alright, I will try that out tomorrow!

And yes, two different host PCs connected to the same RT machine show this behavior.

[cholulteca]

Ok, first of all, I attached the screenshot with the installed software.

Then, I tried to copy the support files to the RT target, but as soon as I hit the "copy support files"-button, I get the following error message:
"Cannot communicate with the specified target.
Confirm that the specified address is correct, the target ist running, and the target has the LabWindows/CVI Run-Time-Engine for RT installed.
You can launch MAX and use the LabView Real-Time Software Wizard to install the software on the real-time target."