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Re: gEDA-user: hydraulic symbols and schematics



Hi Tom,

I'm a mechanical engineer (BSc) with an electrical background (Technical
College).

I have thought of and made a small start for non-electrical symbols for
Piping & Instrumentation Diagrams, with hydraulics and pneumatical symbols
to follow (http://github.com/bert/gschem-symbols/tree/master/piping/).

Another use for gschem, netlist and friends could be the simulation of
distribution networks of natural gas or tap water, maybe even simulation of
drainage systems: ditches, canals and/or large water ways.

It's just a matter entering a schematic representation for connectivity
(nets), adding the right attributes and invoking a scheme backend with
netlist to do your preprocessing and solver stuff (this is the real
challenge, not the schematics).

Just my EUR 0.02

Kind regards,

Bert Timmerman.


> -----Original Message-----
> From: geda-user-bounces@xxxxxxxxxxxxxx 
> [mailto:geda-user-bounces@xxxxxxxxxxxxxx] On Behalf Of Tom Hawkins
> Sent: Wednesday, April 07, 2010 7:41 PM
> To: gEDA user mailing list
> Subject: Re: gEDA-user: hydraulic symbols and schematics
> 
> On Wed, Apr 7, 2010 at 12:02 PM, Stuart Brorson 
> <sdb@xxxxxxxxxx> wrote:
> > Hi --
> >
> >> Obviously gschem is intended for electric circuits, but has anyone 
> >> used it for hydraulic schematics?  The hydraulics industry has 
> >> defined a fairly rich schematic language [1][2] for describing 
> >> hydraulic and pneumatic systems.
> >>
> >> I didn't find a gschem hydraulic symbol library, so I'm 
> attempting to 
> >> build one.  My first stumbling block is the use of filled and 
> >> non-filled triangles, which differentiate hydraulic pumps from 
> >> pneumatic compressors.  Is it possible to draw filled triangles or 
> >> polygons with gschem?
> >
> > I don't think vanilla gschem currently supports filled 
> regions.  But 
> > this is a frequently requested feature, and the folks in 
> Cambridge may 
> > have coded up a solution based upon the whizzy graphic work 
> they have 
> > done.
> 
> Well it appears to fill circles and boxes just fine.  Maybe 
> it just needs the ability to handle arbitrary polygons.
> 
> >
> >> Do you foresee any other difficulties?  ... aside from 
> simulating a 
> >> hydraulic circuit with spice or generating a layout.
> >
> > Actually, my first thought was:  What kinds of simulations (if any) 
> > does one do in hydraulics?  Are there any standard 
> simulators?  If so, 
> > generating a netlist to feed to such a simulator might be an 
> > interesting hobby project.
> 
> We use Easy5 and Simulink.  But Easy5 doesn't run on Linux 
> and both tools are very clunky and neither have a standard 
> format. This year I plan to build some tools in this space.  
> It would be cool to netlist a hydraulic design out of gschem 
> and simulate it with other stuff like embedded software and 
> vehicle dynamics.
> 
> If you look at some hydraulic schematics, you'll see a rich 
> duality between electric and hydraulic circuits.  For 
> example, the pressure drop across an orifice is analogous to 
> the voltage drop across a resistor.  Hydraulic power is 
> pressure * flow (i.e. V * I).
> 
> >
> >> (BTW at Eaton, we have a history of bending EDA tools for our 
> >> purposes.  We used GTKWave to view and analyze vehicle data in
> >> realtime.)
> >
> > Awesome!  How did you get the real time info into GTKWave?  
IIRC, it 
> > only reads .vsd (and other simulation) files.
> 
> We extract vehicle data via. a CAN bus.  We then convert the 
> streaming CSV data into VCD and pipe this into GTKWave.  The 
> command line reads:
> 
> $ readCAN | tovcd - | shmidcat | gtkwave -v -I my.sav
> 
> We put a laptop in the passenger seat when we take our test 
> vehicles out for a drive.  With the analog features of 
> GTKWave, you can see all the vehicle data varying in 
> realtime.  It's really cool.
> 
> 
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> 
> 



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