ShaunR

This may be of help: Inter thread Comms

I was searching for a way of being able to effect events from dynaimically loaded vi's elagantly. These vi's make it very difficult to use with events and generally it gets all messy with globals since you have to wire them somehow. Then I stumbled upon callbacks (never seen them before). And there doesn't seem to be much information about them apart from using with Active X, so I thought I'd knock up an example to demonstrate their enormous member power. The example attaches a couple of callbacks onto a dynamically loaded vi's controls. One callback is an event generator so that any time a value changes on the dynamically loaded vi, our custom event fires in our top level vi. Every time we load a vi, we attach these callbacks, meaning that any vi will generate our event.

Mark I ear hole and a precision digit works best.....lol If you search this forum you will find a IDE addon that enables you to control Labview using voice commands. Most of what you need is in that.

Welcom Markus. Not sure about a good time, but is always interesting

QUOTE (normandinf @ Apr 30 2009, 10:30 PM) Right...lol So it must be impossible to do this then http://lavag.org/old_files/monthly_04_2009/post-15232-1241128886.png' target="_blank">

Whats the micro controller expecting?

You can change the cursor legend font as with any other indicator/control. Just set the font of the cursor legend to "Plain". Then they won't be bold.(If that's all you need to acheive).

QUOTE (bEMOL @ Apr 30 2009, 12:14 AM) If you want to programmatically add tabs to a tab control then use an active X container and browse for the Microsoft Tab Strip. This has the methods to add, delete,clear etc. http://lavag.org/old_files/monthly_04_2009/post-15232-1241110320.png' target="_blank">

There's an example in the Labview examples directory of a tank filling system. Might be worth a look.

QUOTE (jdunham @ Apr 30 2009, 02:45 AM) I'll take a look later...thanks. QUOTE (jdunham @ Apr 30 2009, 02:45 AM) That's an interesting quote. I think just shows that the NI VISA team is not on the forefront of LabVIEW development (to be fair, I don't know how old that doc is). Their API could easily accept a VI reference and invoke VI.Run on it when the event happens. They could also accept an occurence or a queue refnum, but I think it would make more sense to do the VI reference. Then inside that VI you could invoke whichever queues or notifiers or occurrences (or polled globals) you need to interact with your running processes. LabVIEW with a callback (which you can also implement in your own code with a private notifier or a VI reference) is no less event-driven than C code with a callback. Jason You may be right. In fact, there ARE callbacks, in the true definition of callbacks (well in 8.6.x at anyrate). I've been playing with them for my event problem (well its not really a problem, it would just greatly simplify code and maintenance). But VISA doesn't expose the event refnum so you can't attach a callback. Or conversely, callbacks don't accept VISA resource sessions.There is/isn't/probably a way to get at it, but that aspect isn't on my priority list at the mo. I would go one statment further. Labview is event driven (in the context of truly asynchronous events) with a callback, however C is not event driven....ever.

No. Your DAQ definitely won't be enough to drive the motor. Motors are high current devices. You will need a separate power supply and control it via that. I agree with carlover in so much that really you need a dynamic tracking system (as well as it has been done before). You will also probably want to go backwards and forwards, as well as up and down (since the sun tracks in an arc and starts in the east and sets in the west every day) so a single motor probably won't be enough (2) and they will need to rotate in both directions. You might find this useful in thinking about what you want to acheive. Solar Tracking Project Although I'm at a loss as to why it took 13 weeks...lol.

QUOTE (Mark Yedinak @ Apr 29 2009, 09:53 PM) Read the thread again from 7 posts up.

Short answer "yes". We need to know more too. How are you interfacing to the motor (is it RS232 , PWM card, digital card, parallel port, force of will?). Regardless of the interface, you will need a while loop that generates a timed pulse. It'll look something like this There are many examples in the Labview examples directory. I would take some time to look at them as quite often you can modify them to suit your needs.

QUOTE (Mark Yedinak @ Apr 29 2009, 03:50 PM) We were talking about a full Labview development environment my comment was aimed at this QUOTE The LV development environment is very useful in debugging on the fly if you have live code. NI even supports it with a licensing option. Since the OP said he deploys the vi's and anyone can change them (have to have labview on there for that). That is more than $500.

QUOTE (shoneill @ Apr 29 2009, 02:03 PM) Ah. Thats not it then. I'm looking for a way to link events from dynamically loaded vi's So that the vi can basically "hook" the existing event mechanism.

QUOTE (shoneill @ Apr 29 2009, 08:12 AM) I think that's what I'm missing for me to use events effectively from within an encapsulated architecture. Whats the workaround?

QUOTE (manojba @ Apr 29 2009, 08:00 AM) Hmm. Got me thinking. This would be a good one for a Coding Challenge. Who could write the best URL Label XControl. Be nice to be able to just plonk one on the FP.

QUOTE (jzoller @ Apr 13 2009, 09:40 PM) I'm thinking more about the cost of deployment. Exes and dll's are don't require licensing.I'd find it impossible to justify that the customer pays thousands for a full package which he/she never uses just so that they can use my software.

QUOTE (candidus @ Apr 29 2009, 09:02 AM) Much better solution.

The "Specify path on diagram" is the way forward but I don't think that exists in 7.1 (long time since I used that). So you would have to use the old method of creating an intermediary DLL which you can call from the "Call Library Function node" to pass data too and from other the other DLLs. (2D array in and out always worked best for me). Not elegant, but it works.When you create the plugins, if you make their inputs/outpts are a 2D array then your intermediary dll only needs 2 inputs (the dll name and the 2D array) and one output (2D array).

QUOTE (jbrohan @ Apr 27 2009, 02:30 PM) If I remember correctly, you can hook IE using active x to get click info. Might solve your positioning problem. I'll see what I can dig up if your interested.

QUOTE (PaulG. @ Apr 27 2009, 05:44 PM) You can always ignore us (like 90% of the lurkers ). Or you could read it during work time when your paid for it...lol. QUOTE (jdunham @ Apr 27 2009, 04:09 PM) Queues are cool that they can even the load if your data is bursty, but queue or no queue, if you're not processing fast enough, you have a problem that queues couldn't fix. Unfortunately my data isn't "bursty". It is multiple continous streams with control on top. No problems either. QUOTE (jdunham @ Apr 27 2009, 04:09 PM) I would never send data through a queue that wasn't meant for the queue listener. I would just use separate queues to send data to separate loops that were 100% devoted to handling that data. If I were to adopt the same strategy in the current project I would end up with 87 queues QUOTE (jdunham @ Apr 27 2009, 04:09 PM) OK, I give up trying to convince you. We obviously use queues in very different ways. I find them useful, even indispensable. My team's code doesn't suffer from any of those things you say queues suffer from, and we're doing things that you say are nearly impossible in LabVIEW, and they were pretty easy to code up and have great performance and scalability. Ummm. Are you referring to spawning multiple (200+) threads like in the BT client? I don't think that is possible. Especially if you can only have cores x 4 threads. QUOTE (jdunham @ Apr 27 2009, 04:09 PM) It's fine if you don't want to use more queues, but I don't think you'll manage to dissuade the rest of us. So I guess your in the Q or die camp (but suspected that quite a few posts ago)

QUOTE (jdunham @ Apr 27 2009, 09:41 AM) Quite the converse in fact. You would use a queue to "queue" ( or buffer) the messages/data/etc (because you can't process them fast enough) in the hope that they may ease up later so you can get through the backlog. QUOTE (jdunham @ Apr 27 2009, 09:41 AM) Why do you need wait functions if there is data available? Because you may be busy doing something else that is time critical and higher priority. QUOTE (jdunham @ Apr 27 2009, 09:41 AM) Why is the receiver inspecting the data? So many why's. I've already explained that one. QUOTE (jdunham @ Apr 27 2009, 09:41 AM) Why would you let a queue consumer get data that wasn't meant for it? That's what I call a bug. How can you not? Since there is data in the queue how does it know that its not for it? Thats what I call the nature of queues. QUOTE (jdunham @ Apr 27 2009, 09:41 AM) One way I like to think about it is that a queue is a 'dataflow wormhole' between parallel loops. Since you like dataflow as much as I do, maybe that makes it clearer why a queue is so useful. Don't get all Trekky on me now And I know why as queue is useful, in the same way I know that a car is useful unless you in a swamp. QUOTE (jdunham @ Apr 27 2009, 09:41 AM) Well, do a Google search on "Global variables are bad". I got 400,000 hits. They are considered dangerous in every language. I have been using more unnamed queues and notifiers lately so that they are not available globally. Do a search on "kill Bush" and you get 12,700,000. Your point is? This is what NI have to say on it: http://zone.ni.com/devzone/cda/tut/p/id/5317 QUOTE (jdunham @ Apr 27 2009, 09:41 AM) About my version of the sample application, I tried to add some asynchronous behavior to show the power of the queues. Did you read all the diagram comments? I though that would have answered your questions. It would be easy to modify it to match the original more closely. I took all the globals out because I think they are a defect, not a feature. For asynchronous behaviour they are already in while loops. If data is lost, then I'm not really sure what you were trying to demonstrate with the example.