DAQ Board for adaptive acoustic control

[zjinmin@my-deja.com]

I am a research staff at Penn State University. We are developing some
lab prototype to adaptively control acoustic reflection from an object.
In our control system, we have two acoustic hydrophones (sensors) and
one acoustic projector. We need a DAQ board to collect the analog
voltage signals from the two sensors and do some mathematical
assessment and then output an analog voltage signal which will
be amplified to drive the acoustic projector. We have bought a NI-DAQ
board (PCI-MIO-16E-1) and Labview 5.1 specially for this purpose.
However, we found
that the control loop could only run at a loop rate of 1000 loops/S.
The control loop rate is considered as too low since the acoustic
signals from the sensors can be
a sine wave with frequency as high as
15KHz. I therefore post this messgae to this group for some technical
advice. Could you kindly advise me on following issues:

1) Is 1000 loops/S is the typical loop rate the PCI-MIO-16E-1 board can
achieve? We use Labview 5.1 (running under Windows 98) to develop the
VI for the control.

2) Could we use other programming tool (say C/C++ ) to achieve high
loop rate?

3) I visited National Instruments' web page and felt that the RT board
PCI-7030/6040E might be able to do the job. Can this board achieve a
loop rate about 100K loops/S if we minimize the computation to less
than dozens of multiplications?

Your advice is desperately needed.

Yours truly,


Dr Jinmin Zhang

*****************************
Senior Member of Technical Staff
Center for Engineering of Electronic and Acoustic Materials
Penn State University
Tel: 814-8652010
Email: jzhang@engr.psu.edu


Sent via Deja.com http://www.deja.com/
Before you buy.

[Joe Hays]

Dear Mr. Zhang,

You asked:

>3) I visited National Instruments' web page and felt that the RT board
>PCI-7030/6040E might be able to do the job. Can this board achieve a
>loop rate about 100K loops/S if we minimize the computation to less
>than dozens of multiplications?

Unfortunately at this time the LabVIEW RT DAQ product will not achieve the
rates that you need (nor will any standard DAQ device as the board you
already have). As you have noticed, relatively slower control loops---that
are deterministic---can be obtained with the RT Series DAQ devices. National
Instruments is in the process of refining the code to allow increased loop
rates but this will not provide speeds at the 100KHz rates that you've
requested. At this point in time I would recommend looking into
a DSP based
solution. There are DSP based products in the market that should be able to
acheive the rates that you need.

Joe Hays
LabVIEW RT Product Support Engineer
National Instruments