Using DAQ Assistant with a remote system

[GriffE]

I am new to National Instruments hardware and LabVIEW and I'm trying to use an instrument with LabVIEW by using the DAQ Assistant. I am using a PC with Windows Vista and I'm connected through a network to a PXI 8108 controller in a PXI 1050 chasiss. The instrument is just a thermocouple which I am using to get familiar with everything. The thermocouple is connected to the SCB-68 connector block which is connected to a PXI 6221 multifunction DAQ in the chassis. I am able to create a task in MAX under remote system and everything seems to work. What I want to do is use that instrument within LabVIEW, and it seems that in order to do that I need to use the DAQ Assistant but when I do it says that no supported devices are found. I'm wondering if there is a way to get LabVIEW to look at the remote system to see the DAQ and the thermocouple.

Any advice is appreciated.

Thanks

[hecmar.arreola]

Hi GriffE -

You don't need to use DAQ assistant in LabVIEW to communicate to the device.  I'm not familiar with your specific hardware, but try this:

Make a task for your global channel with the sampling parameters you want.

Drag the task name from MAX to a block diagram in LabVIEW.  Right-click the newly created task constant and select "generate example code."  See if that gets you closer to where you want to be.

[GriffE]

I created both a Task and a Global Virtual Channel in MAX and tried to drag them onto the block diagram in LabVIEW and all that was created was a label with the task's name. I didn't see any "generate example code" anywhere when I right clicked it.

[hecmar.arreola]

Hmm...that is really odd that it would be just a label.  It should be a task or global channel constant.

You can also try dropping a task constant from the Functions palette:

[GriffE]

When dropping a task constant, if I click Browse none of my tasks created in MAX under Remote System show up. If I click Create New none of the DAQs show up.

The thing is that I've been playing around a lot with LabVIEW trying to figure this out and it seems to me like LabVIEW just isn't looking at the remote system to see any DAQ device. I keep thinking that there's got to be a way to create tasks in LabVIEW using a remote system or at least create them in MAX and then access them in LabVIEW. Do you or anybody else know whether that's possible.

[hecmar.arreola]

Sorry.  I guess the same techniques don't apply for DAQ on a remote system.  My experience is limited to hardware that is connected directly with a test system that I'm targetting for a LabVIEW application.  When working remotly from a system, I utilize Remote Panels.

Message Edited by Nickerbocker on 10-21-2009 11:38 AM

[Ben]

Maybe I'm behind the times but I thought that RDA (Remote Data Acquisition) was only supported under Traditional DAQ and was dropped about version 8 of LV.

If RDA has been implemented with DAQmx I want to hear about it (for a project coming my way in about 3 months).

Ben

Message Edited by Ben on 10-21-2009 12:43 PM

[Paul_C. · Accepted solution]

Hello All,

Ben is correct.  RDA is no longer supported in DAQmx.  We do have another way to use DAQmx with a remote system.  This is to use DAQmx with an OPC server or simply with shared network variables.  There is a knowledge base article here that should help you get started.  You should also take a look at the developer zone article here.  The basic idea is that you can use a shared variable within labVIEW that is bound to a shared variable on your networked machine.  This way you can write and read values from a DAQmx task.  Take a look at the instructions in the two articles above and let me know if you have any questions.

Regards,

Paul C.

[GriffE]

Thank you Paul. I bound a variable to the MAX created channel and wired it to a chart in the block diagram and it appears to be giving me readings from the thermocouple. I still want to play around with it some more but it seems like it's doing what I wanted.

Thank you everyone for your help.

[mihamm]

Hello,

i have the same problem as GriffE had. The links, posted above do not function anymore. Can anyone help?

Regards

Michael