2009-11-27

SolarLight (2) and gEDA simulation

An update over SolarLight, I finally managed to print waveforms from ngspice in OpenSuse 11.2 . For some reason the interface is not what you would expect and it has become much more complicated to print a waveform than before.
The first time I installed gEDA from the sources (under OpenSuse 10.3), now I'm using a precompiled version from the OpenSuse Science repository, it could be that the precompiled version has the printer interface "disabled" in some way.
Back to waveform printing, under ngspice one would follow the following path to simulate and plot a waveform:
tran 100n 1.5m
plot v(501),v1000#branch

In the case of the SEPIC circuit of a previous post this would run transient simulation until t=1.5ms with a minimum time step of 100ns (try not to have more than a few thousand simulation points), the second line would open a new window with the output voltage and LED current displayed.
Previously when I pressed in the hardcopy button the print interface would appear and I could chose the printer and/or print to file. Now a message appears in the console:
The file "/tmp/hc4803" may be printed with the Unix "plot" command,or by using the '-g' flag to the Unix lpr command.

If you try the "lpr -g" command either the system complains that it is not supported or that no printer is installed.
lpr: Warning - 'g' format modifier not supported - output may not be correct!
lpr: Error - no default destination available.

After installing plotutils I managed to convert the plotted file (hc4803) to almost any known format (for example postscript or png) with the command:
plot --output-format ps hc4803 > hc4803.ps
plot --output-format png hc4803 > hc4803.png

This allows the plots to be printed and included in documents or webpages, the plot looks something like this:

Then I wanted to try out gwave, gwave is a waveform viewer, part of the gEDA package but its use is far from trivial. First in gwave you must run a simulation and then write the data to a file:

tran 100ns 1.5ms
write plotdata.dta

then run gwave with this data.

gwave plotdata.dta

The interface is far from trivial, I was unable to use colours for the plot and I also had error while trying to print a plot, but at least I could see some waveforms. Results may vary depending on your installed system, but here is a screenshot of the program, the waveforms are in gray on black background:


I'm now temped in building the gEDA toolsuite from scratch... but for that I need some more time...

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