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Maksim Kuznetsov

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Maksim Kuznetsov last won the day on April 30 2017

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About Maksim Kuznetsov

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  1. I am now thinking of creating PPL for a Messenger Library, that is the best solution. I remember 2 years ago you suggested: Creating a PPL and relinking VIs in existing actors to that PPL should work. However how would you approach creating the PPL that will also appear in LabVIEW palette for development (as it is now with Messenger Library)? I would like to distribute PPL to developers seamlessly without having them to dig into the PPL and look for particular VIs.
  2. Yes, Dr Powell, this is exactly what I was trying to do. Thank you for diagrams. I also realised it is not possible and shouldn't be possible based on this discussion: https://forums.ni.com/t5/LabVIEW-Idea-Exchange/Allow-type-casting-between-classes-types-in-PPLs-lvlibp-s-or/idi-p/3136231?profile.language=en Why it was necessary? Due to how TestStand Interacts with LabVIEW application instances: http://www.ni.com/product-documentation/14335/en/ TestStand steps tend to use the same application instance as LabVIEW executable (based on Messenger Library), this is why steps that used Messenger Library from another location didn't work. I wanted steps to be easily distributable, so had to keep dependencies (including Messenger Library) next to them. NI suggests to keep LabVIEW steps in PPL, that didn't work for me because it changed the namespace of the library. However, as you suggested, also changing namespace of the actor I communicate to, worked! So now I have two PPLs with exactly same names, but with different contents. One with actor, second with steps. Additionally, to make TestStand use a different application instance I specified a project path for each step (it forces it to use another application instance). Then I continued my experiments and included steps directly into the Actor PPL and it also worked perfectly without having multiple PPLs. Just one Actor PPL, that has API VIs that are called from TestStand. So far so good, it works well. Thank you very much! It is a relief and I learnt valuable things. P.S. Sharing PPL Messenger Library should also work, it will involve a little bit of extra work.
  3. It is a good analogy. It is unfortunate that changing namespace affects the class names and hence brakes the communication. However for my particular task it is essential. I will try to remove the namespace from flattened address and see what happens. Thank you for all of your assistance and support. I highly appreciate it.
  4. I haven't done that because the main idea was to actually have a separate namespace for a ppl and for the executable. It is unavoidable.
  5. To eliminate the misunderstanding. I have 2 applications: One is a built executable, uses messenger library as is from VI package manager. Second is a ppl with one actor inside (possible on a completely different PC). I can't make these 2 applications communicate through a TCP messenger. I understand that PPL changes the namespace of all classes. Hence when flattening/unflattening messenger addresses the namespace is included. That is why communication doesn't work. To solve this I think I need to somehow remove the namespace when flattening and then add it when unflattening (in actor that runs from PPL). What do you think?
  6. Thank you for the link. But, the problem appear even if I just have a single Actor that uses dependencies from ppl. Basically as soon as "Messenger Library" is put in ppl or a library the TCP Messenger brakes (I can send message without reply, but I can't receive replies). Apparently PPL also creates a namespace for everything that is inside and that brings us back to your reply: Is there any easy fix that I can apply to make Messenger Library work from ppl and library? Kind Regards. Maksims
  7. Hi everybody. After couple of more days of thinking and trying, I managed to narrow down the issue to a very simple experiment. Making it work will solve the problem I've been facing for many days. Experiment setup: 1. Create a simple Actor with a TCPEventMessenger (server). Make it reply with some text to the incoming message. 2. Create another Actor that connects to the actor from step 1 (through TCP). Make it send a message (with reply). 3. Add actor from step 2 to project library. 3. Test both actors in development environment, they should communicate perfectly. 4. Create a packed library build specification for project library from step 3. 5. Now open the actor from the freshly built .lvlibp and try to run it. It should fail with a timeout error while waiting for a reply. This behavior doesn't make sense to me. Because when instead of building packed library I build an executable everything works perfectly. Why can't I build a packed library and make it work the same way. P.S. Packed library includes every dependency, same way as in executable. Any advice will be highly appreciated! Thank you in advance and happy new year! Kind Regards, Max
  8. I believe there is a misunderstanding and I am failing to explain correctly the issue that I am facing. Let me please try once again, if you still have patience. I prepared the following diagram: 1. TestStand Actor.exe is launched in LabVIEW Run-Time Server, hence the Messenger Library VIs will be loaded into memory. 2. TestStand Actor.exe runs the sequence file (with any kind of steps) using TestStand API. 3. Sequence File has some LabVIEW steps that are using Messenger Library VIs. LabVIEW Adapter in TestStand automatically uses the same LabVIEW Run-Time Engine Server as in step 1. Hence there will be a name conflict. Ideally I would build all of the LabVIEW steps into a packed library (as advised by NI). Doing that provides a namespace + puts all the dependencies into one file. However, this brakes communication in Messenger Library and steps become useless. Running steps without library produces a naming conflict in LabVIEW Run-Time Server.
  9. Unfortunately that didn't work. The same behavior appears as described in the initial post: "Send Message (without reply)" and "Receive Notification" work, however "Send Message (with reply)" doesn't. What I did was I created an .exe actor which receives and replies with a text message. Then I created a client actor that sends a message and waits for a reply. Source and Build for the client work perfectly. Then for a client actor I created a source distribution and included all dependencies in a library (that included Messenger Library). I also tried putting the client actor itself into a library, but still with no luck.
  10. Yes, you have a very good point here. Usually I follow this approach. However, TestStand Actor is allowed to load any sequence file through TestStand API. The sequence file itself sometimes calls LabVIEW code, which in my case by a coincidence use the same library that is already loaded by a Run-Time engine. For the sequence developer it is impossible to know that his steps will have a conflict in memory once deployed. Thank you for a suggestion about putting Actors and Messenger library under the library. It sounds like a potential solution, I will give it a go.
  11. Yes, the steps are source. I understand that ideally steps should be built and it can be achieved by building them into "packed library". But packed library automatically brake the communication (same as when changing the namespace of the Messenger library). Another possibility would be to build every step into an executable, but then returning errors, setting step input data would become more complex.
  12. Thank you for your reply. Indeed, I built a separate application (.exe) for TestStand. It is using the Messenger Library with TCP input messenger. Actors from other applications connect to TestStand Actor and run sequences, subscribe for sequence finished events, etc. That part works well. The conflict arises when the sequence file itself contains a LabVIEW step that connects to another actor (e.g. valve controller) and sends a command to it. That step also utilises the Messenger Library, but loads it from the folder next to the sequence (to make sure it runs on systems with LabVIEW Run-Time only). As a result I have a TestStand Actor that runs in LabVIEW Run-Time application instance, that actor loads a sequence that has steps that also run in LabVIEW Run-Time. And that's where problem arises. Sequence can't load any Messenger Library VIs because they are already in memory (loaded by TestStand Actor).
  13. Hello Dr Powell and everybody. I am facing some frustrating behavior, already spent many hours trying to figure it out, but no luck. Maybe you could assist me. In my previous posts I mentioned that I have been working on TestStand Actor. Current setup: TestStand API wrapped in Messenger Library. It is calling Steps that also use Messenger Library to send messages (through TCP) to other actors that control hardware. Issue: TestStand Actor and LabVIEW steps share the same application instance. Hence, I am getting a conflicts/errors when trying to run sequences. The same steps work perfectly from normal TestStand provided by NI. I am looking for a way to isolate LabVIEW steps code from the TestStand Actor. It can be accomplished by putting all the dependencies in "lvlib" or "lvlibp". This way Messenger Library in custom steps will have a separate namespace. However when putting Messenger Library in "lvlib" or "lvlibp", my steps can no longer receive TCP replies. Only "Send Message" without a reply address work (if reply address is provided the send message makes the destination address invalid) . Interestingly, the published events are received successfully. Do you know why would "Send Message (without reply)" and "Receive Notification" work, however "Send Message (with reply)" wouldn't? (when Messenger Library is in put in .lvlib) Thank you! Kind regards, Max
  14. Thank you for all the suggestions! Since I based my actor on NI example of TestStand UI the SubVIs were already configured to run in a separate execution and I still experienced blockings. That is why I thought maybe the actor itself has to run in a different execution and posted in this thread. However today I found out that the freeze was caused by a dialog box that was created asynchronously by the TestStand API (e.g. when it noticed that sequence file was changed). There is a "TestStand - Set TestStand Application Window.vi" that accepts VI reference and makes all the dialog boxes modal to that VI (I set it to TestStand ActorNR.vi reference). It works perfectly fine when TestStand Actor's front panel is the front-most window, no blockings. However if another actor's front panel is currently in focus (front-most) there will be no dialog box until I switch the focus back to TestStand Actor front panel. And in this case both actors get frozen until I acknowledge that dialog box. P.S. Simple front panel drag around with a mouse pointer make actors unfreeze. I think it is related to modality settings that I will explore in more details. Thanks again James and bbean. I highly appreciate your time and support.
  15. Thank you both for quick replies. Indeed the TestStand actor also is used as a GUI. So, it makes it difficult to call everything in SubVIs. There are cases when TestStand engine creates popups that automatically appear on top of the actor front panel (hence blocking it).
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