Multi-Channel Acquisition with PXI-4204

[Intern2005]

Hello,

I would like to acquire 2 channels simultaneouly with the PXI-4204 DAQ board.
At the moment I am using a VI for each channel but I have to switch, I can't acquire both ath the same time. So I don't know if there is a multiplexer function or if I have to edit my VIs because I tried to find an example of multichannel acquisition with PXI-4204 but it was not successful. I am using DAQ assistant Vis with Write to LabView Measurement VI. Could you tell me if it is possible to edit them and if yes how?
The second possibility would be to use my second DAQ board E-Series 6052E to acquire the second channel but I have already tried a long time ago and MAX Explorer indicated a conflict between both cards (maybe due to Traditional NI-DAQ and NI-DAQmx) and one board was not set properly and could't work.

Thanks for advices

[Kerouac]

Hello,

Continuously acquire multi-rate analog input using a DAQ Series device requires to sample all the channel at the highest sampling rate and eliminates the undesired points from the slower channels. To do this, you must specify the maximum scanning rate (base) and one frequency divider factor for each of the channels. The NI PXI-4204 has the simultaneous-sample-and-hold capability which eliminates phase delay between channels but all the channels are using the same internal clock. You cannot assign a specific clock to each channel. You will find below an example based on NI-DAQmx programming with labVIEW:

* NI-DAQmx: Multi-Rate Continuous Analog Input for E Series Devices

http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=BCB8746152612330E034080020E74861&p_...

Have a nice day.

Matthieu G.

NI France

[Intern2005]

Hello,

Thanks for this information.
I think I can solve my problem.

In fact, I would like tu acquire both channels during the displacement of my stepper axis connected to PXI-7344 board and Motion accessory UMI-7764.
So I need to SYNCHRONIZE the motion board 7344 (position/displacement capturing) and the DAQ device (4204) by using RTSI method with RTSI-Lines integrated in the PXI-Chassis (1031).

I know I have to use DAQmx VIs since 4204 doesn't support traditional DAQ.

So the problem would concern then the data storage
Because I 've been using until now the DAQ Assistant (express VI palette) and the Wrtie LabView Measurement FIle which save under *.lvm format. Then I had to load in ASCII format in DIadem since the version 8.0 doesn't support TDM format...!:smileysad

Although I've tried many times and many times, I can never load the LabVIEW/Diadem Connectivity VIs from NI Web Site...?!
And is it possible to update LabView 8.0 to 9 to use the Storage VIs so that I can store files directly in native Diadem file formats?

THANKS A LOT FOR YOUR PRECIOUS HELP

B. Tafati

I found some VIs interesting

 by using some One more thing, I can never load the LabVIEW/Diadem Connectivity VIs from NI Web Site...?!
And is it possible to update LabView 8.0 to 9 to use the Storage VIs?

Regards

B. Tafati

[Kerouac]

Hello,

Concerning your MOTION questions, I advice you to post your question on the motion control forum (http://forums.ni.com/ni/board?board.id=240). You will find some experienced developers and motion control specialist in this forum and you will get more easily an answer to your questions.

I do not understand why you speak about LabVIEW 8.0. LabVIEW 8.0 is not released. Which version of LabVIEW are you using, which version of DIAdem? Could you explain with more details what is the problem with saving/loading you data in ASCII format? Why you cannot download the DIAdem Connectivity VIs?

Thanks for the details.

Matthieu G.

Message Edité par Kerouac le 08-24-2005 11:50 AM

Message Edité par Kerouac le 08-24-2005 11:51 AM