On Wed, Apr 7, 2010 at 12:02 PM, Stuart Brorson <[email protected]> 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. _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
