PXI & RT

[jmpugh]

Hello gang!

I'm working on putting together a new test cell and am trying to throw together a PXI system to do it. I did, however, run into a few questions.

I'm looking at the PXI-8145 RT as the controller.  The product overview states that this controller includes an installed LabVIEW Real-Time engine.  Would this mean that we also have to purchase a LabVIEW Real-Time Run-Time License or does it come with it? I understand that we need the LabVIEW RT Deployment module to actually load our program.

And lastly, and this question will probably show my ignorance of PXI, but the PXI-8145 RT runs headless, meaning a monitor is not needed. However, we do want to use a desktop computer in the test cell to start/stop the test as well as read values back from the test. I was thinking the purpose of adding a remote was to achieve this, but when I try to add one to my configuration it removes the PXI-8145 RT. So would I just use the desktop we already have and use it's DIO card to send triggers and read values back from the PXI? Thanks for your help folks!

-- Jase

Message Edited by jmpugh on 08-07-2007 12:09 PM

[reggier]

Hi Jase,

As far as the RT license goes, you should receive the license when you purchase your controller.  Now let's consider your options with the PXI system.  The PXI 8145 RT controller will work great for your application.  You say you want to use a PC to "start/stop" the test.  You could easily do this using any PXI DIO card using triggers.  This would eliminate the PC. 

For the logging, you could write the data to memory and FTP into the controller later to retrieve it.  If you are looking to view the data while the program is running, you will want to look more at a host/target architecture.

If you are truly interested in a PXI system that will mold to your application and perform everything you need, I would suggest getting in touch with your NI Sales Engineer for your area.  If you let me know your area I can get you their contact information.

Reggie Rector ¦ Applications Engineer ¦ National Instruments

[jmpugh]

Thanks Reggier!

I think I will definately be giving the NI engineers a ring, but if you have the time, I do have one more question.

The only thing I am not really sure about is the headless operation. I don't know if we really want it to be headless. Is there an option?

 The test cell will be used to check the wiring on our products. After hooking the wiring up correctly (there are about 50 different wiring connections we need to check) we want the worker to be able to hit "Start" and then have it run the test. A computer monitor will then show indicators for every wiring connection and feedback whether it has passed the test or not. So the worker knows exactly where the wiring problem is should one exist.

I suppose I could use the DIO card on the PXI to send the information to ANOTHER desktop computer with a DIO card and a monitor, but I was hoping we could completely get away from having anything Windows on this test cell.  The IT department here grabs any Windows boxes and installs so much garage it becomes nearly useless.

I guess to sum up my question: If you are running a Real Time OS, can you still see the front panel and get feedback? Thanks again for your help!

-- Jase

[Reggie_R]

Hi Jase,

If you are running this on a RT system, my suggestion would be to have a host computer reading data from the RT target using shared variables, and updating that information on the front panel of the host PC.  This way the RT target will run deterministically and send data through the shared variables to the host.

I'm a bit confused on how you want to trigger things using a DIO card.  You could potentially eliminate any PC needed at the test site if you had a PXI DIO card.  You could send triggers from it to start and stop the test, and then pass any data over a network to a host PC to view on a Front Panel.  I think this is what you are looking for, but I think one of our field sales engineers could help get you set up with exactly how you want to do things.

I hope this helps!
Reggie Rector ¦ Applications Engineer ¦ National Instruments

[jmpugh]

Thanks again Reggie! You have made by day! And now if the temperature would drop below 110 degrees, I might do a few cartwheels.

That is exactly what I was looking to do. I had forgotten all about shared variables. I was thinking I would need two DIO cards to pass the information between the two computers. *smack* My bad.

That was the primary thing troubling me. I was thinking, "Well we will have this lovely RT system running the test process only we have no idea if it is running, if it has stopped, and the status of any of the 50+ tests it is performing."

I'm off to go read up on shared variables now. Thanks again for your help! As soon as I figure out exactly what we need to test (we have every changing product lines so we are trying to figure out the worst case scenario on how many wires we may need to check) I'll definately phone into NI. Just now I'm scouting it all out and I prefer to sound like a moron on a message board rather than over the phone. 😉 Take care!

-- Jase