First to get the waveform from the Velleman Scope, fire up
minicom set to 9600N81 at /dev/ttyS1 (com2 in the DOS world)
assuming you plugged the Scope into the second serial port,
The Velleman K7105 LCD Oscilloscope, outputs a series
of X,Y coordinate point pairs with a header at the beginning,
upon powerup, of any waveform that is on "hold".
Take as many waveforms as you wish, one at a time though, as the
Velleman only holds one waveform at a time. Unless you have the
Data Opto-Isolator you need to unplug the BNC connector that
leads to the probe, which may still be connected to your test
setup, failure to do this could result in damage to your computer
the scope, and or the components in the circuit under test.
To take an input signal into a waveform data file, with the Scope
completely disconnected from the computer, measure your waveform,
and when you like what you see press the Hold button, and turn the
Velleman off. Disconnect the BNC connector, and plug in the data
to RS232 adaptor, I made my own, plugging in both ends, effectively
coupling the Scopes data signal to the computer. Start minicom
with logging activated, and lay in a descriptive filename.
Press the power button. The Velleman upon powerup squirts out one
hundred point pairs, and stops. Close the log file, disconnect
the RS232 data cable, reconnect the BNC turn on the Velleman
Scope, and press the Hold button again to go back to normal mode.
You are now ready to take another waveform.
After you have taken as many waveforms as you like, fire up the
mathematical visualization package called Grace. Don't fiddle with
the defaults, leave'em alone, open the file box, go down to read,
left click, go to sets, left click, go to the filename filter box,
left click, change it to the directory where you stored your
Velleman data, and end it with a star, example:
/usr/home/zap-tek/veldat/*
The right panel below now has your Velleman files, and maybe some
others, locate the one you want by, clicking on one of them, and
home in on the one you want, by using the up/down arrows, and
press enter. You will get a box that says...
Error parsing line 2, skipped
Error parsing line 3, skipped
This happens because of the Header at the beginning of the
Velleman data set, left click OK, and you now have the first
data set autoscaled, and everything, repeat this procedure to
superimpose later waveforms on-top of the existing plot, if that
is what you wish, and upon doing the last one, left click on
Cancel, (not OK, Ok will replot the same data set again, screwing
up the color scheme, which is perfect, if left untouched)
Now go back to the File box, and left click the "Device Setup"
under Print. Set "Device" to "PNG", Set "Filename" to something
with a dot png extension, under "Page" set Size to "Custom", and
Dimensions to 575.00 by 450.00, and units are in pixels, so
select "Pix" in the selector box to the right. I left the
"Resolution" at the default "72 Dpi" personally I don't see how
Dpi, eg. dots per inch, has any meaning in a PNG file. Under fonts
turn off antialiasing and device fonts, then click on Accept.
Now to actually generate a PNG file, left click on File, go down
to "Print" and left click on it. Instantly you have a file with
the name you laid-in that is a PNG file, and scaled as I use with
my webpage. I then use Xpaint to crop, and annotate the resulting
dot png file.
You can learn more about this amazing
LCD Data Scope
but this is an offsite link so remember your back button, or better yet
bookmark where you are now. Note this is not an endorsement, I simply list
it here, cuz, it's the one I use, and I've had real good luck with it, your
mileage as they say, may vary.