The huge advantage you get with RT-Linux is that you can make a LabView program that
has real time properties. There is more to real time software than eliminating gaps
in data acquisition or data acquisition in general. Yes, they have made special
hardware to capture buffers of data to eliminate the gaps. However, the software can
not make real time decisions based on the data that was captured. RT-Linux allows
you to provide: real time data acquisition, real time decisions based on that data,
and real time control signals out to the physical world. LabView by itself does not
allow real time processing.
With RT-Linux you can have several different real time processes working together and
still maintain their real time properties. In LabView there are some priority
settings that can be assigned to separate threads but none of them are real time. As
other threads get higher priorities some threads suffer from a loss in performance.
National Instruments does have a special board with a DSP to provide some real time
control. From what I have seen so far it is limited to general purpose stepper and DC
motor (pulse width modulation) controls.
> ----------
> From: Dan Samber[SMTP:[EMAIL PROTECTED]]
> Sent: Thursday, May 11, 2000 11:19 AM
> To: Basham, Richard R; '[EMAIL PROTECTED]'
> Subject: Re: FW: [rtl] Labview
>
>
> I have a naive question:
> How does Labview benefit from RTLinux? Alledgedly, the people at National
> Instruments
> have arranged things (via special drivers or some other mechanism....) so
> that there
> are no ugly things like gaps in data acquisition etc.
>
> Can someone clear things up for me?
>
> Thanks,
>
> Dan
>
>
> At 04:09 PM 5/10/00 -0700, Basham, Richard R wrote:
> > > I have been using LabView with RT-Linux for over a year now. It has
> > worked out quite well.
> > >
> > > I use the LabView to deal with the mundane user interface and non time
> > dependant things such as file access. I have displays that present near
> > real time information from the real time processes for the operator to
> > view. I also provide button commands that control some of the execution
> > of the real time processes.
> > >
> > > I use a shared library of small routines to pass the data back and
> > forth between LabView and RT-Linux. These routines access both shared
> > memory and the RT-fifos.
> > >
> > > I used the initial execution of the LabView program to install the real
> > time modules and I also had LabView remove the modules in an orderly
> > fashion when the program was terminated. This was important because some
> > of the users of the project did not want to be bothered with the low
> > level details required to make it work. They just wanted to be able to
> > use it and they really wanted to have a single point of entry and exit.
> > >
> > > The largest benefit that I got from using these two products together
> > was that I was able to produce the graphical user interface quickly. It
> > is easy to change the interface when new requirements arrived.
> > >
> > > I will admit that I have had about 40 hours of training in
> > LabView. However, it was about a year before starting the
> > project. Furthermore, this was the first project in which I used LabView
> > since the training.
> > >
> > > I was hoping to put together a little write up on how I interfaced the
> > two products with each other and send it to the news group. I wanted to
> > include code examples etc. However, every time I think I have some time
> > to do that I get a couple more jobs piled on. If this is of interest to
> > other people I may be able boost the priority.
> > >
> > >
> > > Richard Basham
> > > Control Systems Group
> > > Environmental & Material Test Laboratories
> > > Boeing Defense & Space
> > > Seattle, Washington
> > >
> > >
> > >
> > > ----------
> > > From: [EMAIL PROTECTED][SMTP:[EMAIL PROTECTED]]>
> > > Sent: Wednesday, May 10, 2000 1:12 PM
> > > To: [EMAIL PROTECTED]
> > > Subject: [rtl] Labview
> > >
> > >
> > > If you are interested in Labview on RTLinux, please send me a note.
> > > Tell me if you are currently using Labview, and, if you
> > > can, why you want RTLinux/Labivew or a similar product.
> > > Other comments on Labview and RTLinux gladly accepted.
> > >
> > >
> > >
> > > --
> > > ---------------------------------------------------------
> > > Victor Yodaiken
> > > FSMLabs: www.fsmlabs.com www.rtlinux.com
> > > FSMLabs is a servicemark and a service of
> > > VJY Associates L.L.C, New Mexico.
> > >
> > > -- [rtl] ---
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> > > ---
> > > For more information on Real-Time Linux see:
> > > http://www.rtlinux.org/rtlinux/
> > >
> > >
> >-- [rtl] ---
> >To unsubscribe:
> >echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
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> >---
> >For more information on Real-Time Linux see:
> >http://www.rtlinux.org/rtlinux/
>
>
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