Very Computer

Hi all,

I have a bit of a problem with real time/non real time data
communication, and I'm
hoping someone can help me. We have a real time process, which will be
running on
an embedded processor under RTLinux2.0 (Linux kernel 2.2.13).

This process is logging data from a set of sensors, and writing the data
to a file
or buffer, in real time. I'd like to be able to do online data
visualisation on
a host machine, connected to the embedded system via Ethernet. I figure
that
the real time process can write the data to a real time FIFO, and that a
non-real
time process (a normal Linux process running on the embedded processor)
can pull the data out of this buffer and send it over the Ethernet, as
time permits.
I would then have a data stream coming into the host, (running Linux or
Windows)
for which I ought to be able to find some tools to do pseudo-real time
plotting
(sort of like a 'scope on slow trace).

Has anyone done this sort of thing before, and if so, do you have any
example
code/hints/tricks? I'd appreciate any help.

Thanks,

Robert Sheridan

Lutz:

It seems to me that the data could be written to a hard drive on the
embedded machine. YOu could then NFS from the embedded machine, and write
the program on the "Monitor machine"  to read until EOF upon startup, place
a marker of some sort at EOF, then every 5 seconds or so, search from the
marker to EOF, write a new marker, etc, etc, etc....

Something to that effect should work for you, maybe... Depends on wether the
embedded machine has a hard drive to write to, and a way to allow NFS...

Just my two cents.

-SSB

Hi,

have a look at rtnet found at
http://www.zentropix.com/products/download.html
Perhaps that helps ?

bye

Klaus

http://ee-staff.ethz.ch/~oetiker/webtools/rrdtool/

Quote:> an embedded processor under RTLinux2.0 (Linux kernel 2.2.13).

> This process is logging data from a set of sensors, and writing the data
> to a file
> or buffer, in real time. I'd like to be able to do online data
> visualisation on
> a host machine, connected to the embedded system via Ethernet. I figure
> ...

--
timothymoore
   bigfoot
     com

[...]

Quote:> I would then have a data stream coming into the host, (running Linux or
> Windows)
> for which I ought to be able to find some tools to do pseudo-real time
> plotting
> (sort of like a 'scope on slow trace).

Lutz,

If you just need simple graphing, have a look at the graphing tools
available for Linux. Some accept a pipe as input. Sorry not to be more
specific.

Johannes Nie?

What does the industry do ? SIEMENS has a Database Sybase in which the
Process values are stored...
So whoever needs process values accesses the Database..
I'm very interested in your application, so please reply if interested .

--
HUYSMANS Werner

(Mail is not read every day!!!, be patient)

Quote:> Hi all,

> I have a bit of a problem with real time/non real time data
> communication, and I'm
> hoping someone can help me. We have a real time process, which will be
> running on
> an embedded processor under RTLinux2.0 (Linux kernel 2.2.13).

> This process is logging data from a set of sensors, and writing the data
> to a file
> or buffer, in real time. I'd like to be able to do online data
> visualisation on
> a host machine, connected to the embedded system via Ethernet. I figure
> that
> the real time process can write the data to a real time FIFO, and that a
> non-real
> time process (a normal Linux process running on the embedded processor)
> can pull the data out of this buffer and send it over the Ethernet, as
> time permits.
> I would then have a data stream coming into the host, (running Linux or
> Windows)
> for which I ought to be able to find some tools to do pseudo-real time
> plotting
> (sort of like a 'scope on slow trace).

> Has anyone done this sort of thing before, and if so, do you have any
> example
> code/hints/tricks? I'd appreciate any help.

> Thanks,

> Robert Sheridan

For datavisualisation with net interface look for example at

http://www.iaee.tuwien.ac.at/sensor/samplin/

The Program is called SampLin by Mr. Kvasnica;
its a a kind of script language combined with a nice and very easy to
use real time graphic. We are using it for 1,5 years in a linux based
rheometer for the online display of torque , speed, temperature, time
and
status signals

Markus Greim