Help with LabVIEW DAQ application architecture

[Kenny_K]

Here is a very simple template based on some of your requirements.  I will try to add in some more, but it should give you an idea of how to use the state machine to go through the different states.

[PaulG.]

I didn't get to see KennyK's suggestion since I'm still stuck in 7.1. But my $0.02 is attached, too. You can add states, change sequences, etc. Break a leg!

PaulG.

[Kenny_K]

Here it is in 7.1.

Paul, the vi did not get attached to your post

Kenny

[PaulG.]

Ooops. OK ... let's try this again ..

[webcmc]

Kenny,

Thanks for the template. I have some experience with state machines and producer consumer loops (both data and event driven), so your design makes sense to me.

My big struggle with this is in the controlling of the actuall acquisition timing. I need to be able to collect and log low speed data (1 Hz sampling rate using compact fieldpoint with 5 modules (2 AI, 1 TC, 1 CT, 1 DIO) throughout the test, but use only the data collected during the Set Point Duration to perform the limit testing.

I would also need to collect and log high speed data (5 channels around 24kHz sampling rate) during the set point duration and perform some limit bounds checking after running the HS data through RMS and FFT functions.

How would I coordinate that type of timing based on the state machine model? Would I have separate Prod. / Cons. loops handling the LS and HS DAQ over the course of the entire test and use the given state machine model to try and identify the sections of the collected data to run the limit tests against as the data accumulates? (this is actually the approach that I got from one of the NI guys, but I haven't been able to implement it 🙂

Thanks again for all the help.

[webcmc]

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@PaulG. wrote:

Ooops. OK ... let's try this again ..

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Paul,

I think there is a 'messagebox.vi' missing in your VI.

- Chris

[Kenny_K]

I like Paul's approach of using the VI server to load the subvis that run in parallel.  I will be saving the template for some later projects.  Thanks Paul

Kenny

[webcmc]

I like it was well, however, I'm not sure how I'm going to update the UI with 'real time' values as they are acquired if that process is in a sub vi.

The other problem is how to synchronize the acquisition timing between the high speed, low speed and controls when they are in separate VI's. This is really the root of my trouble and the part I really don't understand.

- Chris

[PaulG.]

Chris: the messagebos is not important. It's simply a souped-up version of the message box vi. The framework I posted was stripped down from a main vi that controls up to 6 'main' subvi's. All in all the main application loaded over 600 vi's and 22 states. I simply forgot to delete everything.

PaulG.

7.1 with 8.2 "in the mail"

[PaulG.]

Chris: functional globals are very useful in storing and retrieving data from vi's running in parallel. When the equipment is running and acquiring data you simply put the data in the USR. When another part of your code wants that data simply call up that data vi and get it. You can put the data in one program, then get it in another program that's running in parallel. Hope that helps.

PaulG.

7.1 with 8.2 "in the mail"