I would also like to hear about any projects that incorporate java and rtl.
My organization would like to use rtl with a java "core" (includes GUI) to
display and log real-time data. Another organization, who may or may not
use linux, will process and study the logged data. The advantage of the
java core is that it can be reused on other platforms to "replay" the logged
data. The idea is to write all real-time functions in C and use JNI to
invoke the functions from the Java "controller." This idea has not been
prototyped, so i'd appreciate any comments or suggestions.
Thanks,
Rob
[EMAIL PROTECTED]
> -----Original Message-----
> From: John [mailto:[EMAIL PROTECTED]]
> Sent: Monday, November 23, 1998 9:14 AM
> To: [EMAIL PROTECTED]; Donald Gaffney
> Cc: [EMAIL PROTECTED]
> Subject: Re: [rtl] LabView for Linux
>
>
> Hi Folks!
>
> This is my first exposure to Linux and rtl. I just got Red
> Hat 5.1 up and
> running this weekend and I am very impressed. Java Beans are
> very "visual
> basic" like and there are lots of "visual" type tools for
> Java. Perhaps
> there are some people in the Real Time world who have found
> public domain
> Java Beans for Man Machine Interfaces (MMI) ??? I haven't
> actually done any
> Java yet but, I would be interested in hearing about any rtl
> Java projects.
>
> - John K. Phelps
> [EMAIL PROTECTED]
>
>
> At 12:07 PM 11/22/98 +0000, Reg Dunlop wrote:
> >Following up on Don's Lab View note:
> >
> >The main PC Lab View limitation is the Windows operating system
> >which disables the interrupts for various time intervals. It can do
> >"real time" data collection by using timers and FIFO stores on the
> >ADC board so that the CPU isn't involved in real time transfers. The
> >CPU must unload the FIFO before an overflow occurs but that isn't
> >real time.
> >
> >The Automation Lab at the Swiss Technical University at Lausanne
> >(EPFL), Switzerland have been using Lab View for real time input &
> >output (they do control of an inverted pendulum, helicopters etc.)
> >on Power Macs which have a clean interrupt structure (unlike
> >Windows).
> >
> >The Power PCs are expensive to buy, hence my use of PCs, and my move
> >to RTLinux. Now if someone could just port over those "visual basic"
> >type tools to X-Windows....
> >
> >
> >> On Thu, 19 Nov 1998, Basham, Richard R wrote:
> >>
> >> > In case some of you do not know anything about LabView,
> it is a graphical
> >> > language. It allows the "programmer" to attach icons,
> that define
> >> > functions, together to create a program. I am a tried and true C
> programmer
> >> > myself and believe that it is a better language.
> However, LabView has
> one
> >> > standout quality. It has the ability to let the
> "programmer" build nice
> >> > looking graphical user interfaces. It is a fast easy
> way of producing
> data
> >> > displays with graphs, thermometers, gauges, buttons,
> etc. What I have
> found
> >> > is that for my applications, 1 ms periods and better, it
> does not perform
> >> > well by itself. However, combined with RT-Linux I think
> it can be a very
> >> > useful tool. I do not have it myself. I plan on
> purchasing it soon. If
> >> > there are others out there who have been using it or are
> planning on
> using
> >> > it, I would like to here your reviews.
> >>
> >> LabVIEW is a good hook for some beginners that need to get
> something done
> >> quickly; it is, in a sense, the "Visual Basic" of data
> acquistion and
> >> instrument control. I would say its performance is poor
> and unsuitable for
> >> real-time tasks requiring sub-Hz periods (this has a lot
> to do with the
> >> fact that I have run it on Windows systems (i.e. 95/NT)
> which are not
> >> really suitable for real-time work with a short period).
> The Linux version
> >> could be coupled to an RT-Linux task through a custom
> C-interface module,
> >> so I guess it could make a reasonable, albeit expensive, front end.
> >>
> >> I have used it for a few straight acquisition projects and
> found that it
> >> was just 'ok' - I did not find graphical programming to be
> faster or
> >> better than C (especially if it was used to read older
> binary data files
> >> - I found building "structures" somewhat painful), and you
> lose easily
> >> parsed text. I also did not find that it was easy enough for
> >> non-programmers to use, which was an initial selling
> point. Programming is
> >> a skill in itself, the tools don't create programmers from
> non-programmers
> >> no matter how pretty they are.
> >>
> >> The graphical controls, or widgets, are quite pretty
> though; I have used
> >> the NI Component Works library on NT/95 just to get those
> pretty widgets.
> >>
> >> There has been talk recently on the llp list and elsewhere
> of building a
> >> better LabVIEW-like (but non-graphical) system for Linux.
> I believe Tcl/Tk
> >> was being thrown about as the top-level programming interface.
> >>
> >> > If there are other easy to use graphical display
> builders or libraries
> out
> >> > there I would like to know.
> >>
> >> Many projects given here have used the much ballyhooed Qt
> library from
> >> http://www.troll.no/ - this library is used in some
> example programs from
> >> Victor Yodaiken's lab (Bill Crum's examples?), I believe, and David
> >> Christini employed it as well. It is very nice. Qt is now
> sort of open
> >> source, and free for non-commercial software, it is the
> basis of the KDE
> >> project.
> >>
> >> I have taken to using FLTK (fltk.easysw.com) which is
> LGPL'd and cross-
> >> platform between Win9X/NT, Linux, and SGI. It has a few
> nice widgets
> >> (look at the 'valuators' - especially the roller), and is
> under active
> >> development. It's big advantages are in its OpenGL support
> and the fact
> >> that it is a small static library - the execs are small
> and distribution
> >> is mindless.
> >>
> >> Other folks on llp have used Tk with BLT to handle the GUI
> >> (http://www.scriptics.com/).
> >>
> >> None of these toolkits contain the variety of pretty
> widgets from National
> >> Instruments. On the upside, all of them are open source in
> one sense or
> >> another, so there is less of a problem with vendor lock-in or
> >> inflexibility. They are all cross-platform in some sense
> as well, although
> >> Tk is the only solution which excels in this area (Qt will
> cost $$ to
> >> move back to Windows and there is no Mac support; for
> FLTK, Mac support
> >> is "in the works" but is not yet available).
> >>
> >> My opinion on LabVIEW (and by extension Visual Basic) is
> that it is great
> >> for small projects and prototyping. The downside (of both)
> is that they
> >> are relatively difficult to interface with outside code,
> can be difficult
> >> to maintain as projects grow, and they lock you in to a proprietary
> >> technology. You say that there is an educational discount
> for LabVIEW, but
> >> my copy of 4.0 still ran over $700.00, If I recall
> correctly, and to setup
> >> the same code on all of the researchers' desks would cost a mint in
> >> additional licenses. The runtime kit did not seem to be an
> attractive
> >> option either. Either way, in the end, you pay.
> >>
> >> -Don
> >
> >Best regards,
> >
> >Reg
> >
> >Dr G R Dunlop, Dept Mechanical Engineering, University of Canterbury,
> PB4800 Christchurch, New Zealand
> >[EMAIL PROTECTED] ph ++64 3 364-2386 fax++64 3 364-2078
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> >http://www.rtlinux.org/~rtlinux/
> >
> >
>
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