using PC to monitor the measurement taken using PXI1024Q

[engkokyen]

i'm currently working on a project which i have to design a monitoring system for a pilot plant for educational use. so basically, the monitoring system is developed using LabVIEW 8.0 and the measurement is done by attaching sensors, transmitter to NI PXI1024Q with M-series multifunction DAQ. the NI PXI1024Q is bundled with MAX but not LabVIEW, so the LabVIEW 8.0 is installed on another PC and the system is developed and that particular PC will be connected to PXI1024Q using ethernet conection. for all the measurements taken by the DAQ will be collected and passed to the PC so that measurements can be shown on that PC for all the parts being measured (monitoring). my problem is that i cannot detect the hardware (M-series multifunction DAQ) using the monitoring PC, thus monitoring cannot be done because the DAQ assistant in LabVIEW stated that no devices are detected, even though a connection had been established. i'm not sure what is the cause of the porblem, it can be the connection problem, or it can either be the software or hardware problem. it came to my attention that my case is actually a remote computer case, so the software that i should use is LabVIEW Real Time, is it true??? and for extra information, i can't even detect a remote system in MAX. how can i solve the problem??? i hope i can get some explanations and guidances for this matter. the help given will be very much appreciated, thank you.

[Prashanth]

Hi There,

I think you meant you were using 1042Q pxi chassis. What controller are you using on this pxi chassis? OR are you using a MXI setup? Are you using/installed LabVIEW RT?

Regards,
Prashanth

[engkokyen]

oh yeah i've made a mistake. i'm actually using a PXI-1042Q chassis installed with PXI-8196 Embedded Controller and PXI-6289 M-series Multifunction DAQ, it also has monitor, keyboard and mouse connected to it. as for the software platform for the chassis, i only have Windows XP, drivers and MAX installed, because this is a bundled unit and that's what had been installed for me, it has no LabVIEW8.0 or LabVIEW RT. as for the PC, i have LabVIEW 8.0 and some drivers installed in it, including MAX. and again, i'm not using any LabVIEW RT, and i'm not using any MXI as well, no VISA, no Fieldpoint. the connection i used is TCP/IP, a network connection to connect the PC to the PXI. i have the I/O device installed and i managed to take reading using the PXI, but i have problem transfering those readings to the PC to display it using LabVIEW on a panel diagram. i'm taking many measurements (around 20 measurements) and simultaneously i want to display those measurements on the PC which connected to the PXI. i know i can't use DAQ assistant or DAQ express VI because the M-series DAQ is not installed in the PC, and obviously i'll get the message saying 'no supported devices found'. and i've tried to use remote desktop connection, all it did was to give my PC the authorization to control the PXI only, i can't display the measurements on LabVIEW.

i know actually from the PXI itself i can monitor the readings using MAX, but that's not really what i want. i want to display a diagram of the whole plant and show the measurements beside the sensors and transmitter, so that the end user can monitor the plant and all the measurements. i've try shared variable method, but sadly i don't have LabVIEW 8.0 install in the PXI so i can't host the variable and share it to the network. however, i have doubt on using shared variables. the question is, does the shared variable method need LabVIEW RT??? does LabVIEW 8.0 it self is sufficient to do the work? instead of RT (real time), what else can i use/do to help solve the problem? web hosting is also fine, as it needs Visual Basic programming, so that'll only be my last option if there's no more option left to me. if that is the case, what is the requirement (hardware and software) to do web hosting??? and for any solution (other than web hosting) that you (the reader) suggest, pls list the requirement for it, so that i can make sure that i have both the hardware and software to get it done.

thank you.

regards,

engkokyen

[Jarrod_S.]

Hi engkokyen,

You can monitor channels on your DAQ board on your PXI system from your PC that has LabVIEW 8 installed, even if the PXI system only has MAX installed. The first thing you will want to check is that the PXI system has DAQmx 8.0 or higher. This will be required. DAQmx is a free download for NI customers from ni.com/downloads, if you need to upgrade versions.

What you can do is bind a shared variable on your PC to a global channel for your M Series card. The shared variable when then poll that global channel at a specified rate and update itself with the scaled value. It's important to note that this is not an optimal solution. By default the server polling rate on your PXI system is not very fast, and even if you do increase it, you're still dealing with software timed acquisitions. So if you're wanting acquisitions less than 10Hz or so (and this is just an estimate off the top of my head), you'll be fine with this method. But if you need to be taking frequency measurements or some such thing, this will not work so well.

So what you will want to do is create Global Channels for all the sensor channels on your PXI machine. Then from your PC, create shared variables in your project of data type double precision numeric. Then bind those channels to your newly created Global Channels on the PC. I'll post some links below that give more information on this topic.

http://zone.ni.com/devzone/conceptd.nsf/webmain/995D38F6D8CF57BB8625706700529F3F
http://digital.ni.com/public.nsf/websearch/AA2C53473923CC22862570CA00543602?OpenDocument

Another option, which is better if you need to make buffered hardware-timed acquisitions, would be to create a LabVIEW executable on your PC system and port it to the PXI system. You would need the Application Builder on your PC. This comes with the Professional Development System. Then, all you would need on the PXI system is the LabVIEW Run-Time Engine, not LabVIEW itself. Hope this helps!

[engkokyen]

hi Jarrod,

thank you for all the information, it's very helpful indeed. i'll try the first option first, the global channel and shared variable method, see if it suits my needs.  as for the second method, how do i know i have LabVIEW Run-Time Engine on the PXI system??? when i run MAX, under the software tree, i can't locate LabVIEW Real-Time. is it an optional platform/software for the system?? is it pre-installed on every PXI system?? is there any link that i can visit to learn how to apply that method??? i've refer to the HELP in LabVIEW, i need to create a boot disk to boot the PXI.  to my suprise that the option is not applicable, because i can't click on it.  is there any tutorial or example that i can follow??

sincerely,
engkokyen

[Jarrod_S.]

Hi engkokyen,

You should note that there is a difference between LabVIEW Real-Time and the LabVIEW Run-Time engine. LabVIEW Real-Time is a module for targetting VIs to real-time operating systems. It does not sound like you are using this module at all. The LabVIEW Run-Time engine allows you to run LabVIEW-built executables on machines that don't have LabVIEW installed. You can download this from ni.com/downloads for free and install it on any Windows 2000/XP machine you like. Or, if you build an installer from the LabVIEW development system for your executable, you can package the LabVIEW Run-Time engine with it. You can also include all the necessary drivers, so when you install the application on your PXI system, you will have everything you need.