NI DAQmx read VI.

[Azzam87]

Hello all,

I have the following system:

NI PXI-1042Q chassis

NI PXI-8106 RT Controller

NI PXI-6289 M series DAQ and its corrsponding software

LabVIEW 8.6 (LabVIEW real time module is included)

the host computer is running windows VISTA Home premuim.

I want to use the DAQmx read VI, I am not finding it. I would like to ask if this VI is no more usable with real time enviroment or I have a problem.

If it is no more usable what is the alternative way in order to be albe to read and write data to the channels of the M device.

Best Regards!

[Hillman]

Hi Azzam86,

Good afternoon and I hope your well today.

Thanks for your post.

You CAN use the DAQmx API on PXI LabVIEW Real-Time targets.

In-order to develop your code you must have DAQmx installed on the development machine with support installed for your version of LabVIEW. To be able to deploy your code successfully to the PXI Real Time target you must ensure you have the DAQmx driver install on the controller too. 

Using Measurement and Automation Explorer (MAX) can you see the PXI RT controller( under remote systems)? If so,  under the software tab is DAQmx listed? Also, under My System, software, is DAQmx listed? 

Ensure you are using NI-DAQmx 8.7.2 or later, as this was the first version to support LV 8.6 an LVRT 8.6.

NI-DAQmx 8.7.2 - Windows 2000/Vista x64/Vista x86/XP

http://joule.ni.com/nidu/cds/view/p/id/1087/lang/en

*When installing make sure you install for your version of LabVIEW. If your unsure, if you go to control panel, add/remove programs and click to re-install the driver, it will confirm what you have install and what you can add to the current installation. 

How are you trying to program the PXI? Have you got LabVIEW Real Time installed? Once you have, you can create a real time project. Then setup the PXI chassis with the correct IP address, and connect. Then load one of the DAQmx examples from the NI Example Finder, (Hardware I/O>>DAQmx) and then try to deploy this, does it work? does it find the VIs?

The VIs should be found under Measurement I/O>> DAQmx - when you right-click on the block diagram of any VI.

Hope this helps,

Message Edited by Hillman on 06-02-2009 12:20 PM

Message Edited by Hillman on 06-02-2009 12:21 PM

Message Edited by Hillman on 06-02-2009 12:23 PM

[Azzam87]

hello Mr. Hillman,

I woulk like to thank you for your reply.

I woul like to ask:

   under Measurement I/O I find NI scan engine............what about it is it an alternative???

Berst Regards!

[Hillman]

Hi Azzam87,

Thanks for your reply. Did you manage to resolve your first problem?

NI Scan Engine is a few feature of LabVIEW 8.6. It allows programming cRIOs and RT Series PX without using the FPGA. It has maybe advantages in terms of easy of use and time saving, but it limited to 1kHz data rates - because it automatically updates shared variables with the I/O information which you can the access directly in LabVIEW. 

For more information please see the following link, it all applies to the PXI FPGA cards too.

Using NI CompactRIO Scan Mode with NI LabVIEW Software

http://zone.ni.com/devzone/cda/tut/p/id/7338

Recommended Practices for Using the LabVIEW I/O Variable and NI Scan Engine

http://zone.ni.com/devzone/cda/tut/p/id/7694

There are also extra VIs to allow mass readings from channels and modules, to improve of time saving and easy of use. These are known as the Advanced I/O Access VIs for NI Scan Engine. Please refer to the link below for more information,

NI Scan Engine Advanced I/O Access

http://zone.ni.com/devzone/cda/tut/p/id/8071

Are you interested in using the NI Scan Engine in your application?

[Azzam87]

Mr. Hillman,

your help is so valueble to me, I real appreaciate it,

Regarding my first problem......  I am still downloading the new version of DAQmx, and is takeing so much time.

Regarding to the NI Scan engine.....I have figuered out that it is a little bit complicated.....I prefer to wait the new version of DAQmx and see what will happen.

Thanks so much.

[Hillman]

Hi There,

No a problem!

I just wanted to  clear one thing up, NI Scan Engine is part of the NI-RIO driver, this is different to NI-DAQmx. NI-RIO (and Scan Engine) is for FPGA based products, such as the R-Series boards and the cRIO (Real Time Target). On these products you can't use DAQmx.

I hope that makes sense,