Configure 6225 in PXi to communicate with PC

[MarkfromSAGE]

I'm a relatively experienced LV programmer but am struggling a bit with the folowing.  I want to use an NI-6225 installed in a PXi chassis to do data acquisition.  I would prefer to run the program on a PC rather than download it to the PXi RT module, but am having trouble finding the PXi in my LV device lists.  My physical set-up is as follows:

I have a PC running LV 7.1.1 and LV2009, which is being used for the development.  I will eventually port this to another machine as an exe and run it with the runtime engine.  The PXi is on a Static IP on the LAN.  I can access it using VISA and am using the built-in serial port to control an external voltage source which will then generate signals to be read into the ADC. 

I spent some time trying to set up a virtual channel via MAX, but it complained that my software on the target and on my PC were different versions. Before i start down any course of upgrading software, etc. I would like to understand what I am trying to do.  Is it possible to use the NI-6225 as a remote ADC or do I have to run the application on the PXi?

Any help appreciated...

thanks.

[Christian Mergl]

Hey

So your System Setup ist something like this:

HostPC(LV for Windows) -------- Ethernet --------> PXI (LV Realtime) --------------> DAQ Card

With this setup you typically would have a realtime application doing the data acquisition in a time critical loop and transfering the data to the host with a normal priority loop.

The communication could be TCP/UDP, STM, Shared Variables or Network Streaming API (since LV2010). At the host your run the UI and other stuff like communication to a database.

The other way, which is really a bad way, would be to use VISA to communicate directly with the DAQ Device from the Windows host. But with this you will need to do Register Level Programming.

The setup you would want, would be a MXI Bridge. This means instead of the PXI Controller you would have an MXI Connection to the PC or Laptop, which makes the PXI Chassis appear direclty as PCI Bridge and you will see your DAQ Card as it would be installed in your PC or Laptop.

Christian

[MarkfromSAGE]

Christian,

You have pretty much nailed it.  I was hoping there would be an easy way to directly address the DAQ card, but judging from your reply, I'm better off running an application on the PXi and monitoring the process from the PC.  This leads me to a further question:  When I originally started this project, I was running LV 7.1, and in order to implement a program on the PXi I had to upgrade to 7.1.1.  I have subsequently upgraded my development environment to LV2009.  Now when I try to look at the PXi, it tells me that the versions of the DAQmx driver versions are different on the local and remote systems.  When I went to upgrade them, there was a whole slew of dependencies.  Do I need to upgrade everything, and if so, am I forced into using LV2009, or is there a trick?  Also, where can I get the latest LV real time driver?

Thanks for you help.

Mark.

[Christian Mergl]

Hey!

Well, the problem your are facing now is that you can only have one DAQmx version installed on your system, and there is no version which supports LV7.1.1 as well as LV2009.

The latest version supporting LV7.1.1 will be DAQmx 8.9, whereas the oldest version supporting LV2009 is 8.9.5.

You will find a compatibility list here: http://digital.ni.com/public.nsf/allkb/F4E76EC05118F72D8625773000672298

I would recommend to use LV 2009 SP1 (and for sure also LV RT 2009) with the latest DAQmx. Especially when working with different targets there have been some major improvements since the release of LV 8.0, e.g. to have everything in the labview project.

You can download the software under ni.com/src.

Hope this helps,

Christian