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Re; Pasco Interfaces



Ed Schweber (edschweb@ix.netcom.com)
Physics Teacher at The Solomon Schechter Day School, West Orange, NJ

Mark Sylvester wrote in reference to Pasco Interfaces:


I managed to get the SCSI card to work under WNT, but at the >cost of using
the ethernet card. Still haven't got round to fixing >this.


Last year I had only one Gateway computer running under Windows 95 and
the only problem I had with the interface was an IRQ conflict. When my
school went heavily into computers this summer, I got five additional Dell
computers and we switched to Windows NT. I then a significant amount of
trouble with the Adaptec Card, which I finally resolved by loading the
appropriate driver. Since I was having several driver problems at the time,
I no longer remember where I found this particular one. But I was put in the
right direction by Pasco support. Then again, although my school is wired
for networking, our new network administrator has not actually gotten around
to networking the physics lab and I don't know what problems may arise after
we are networked.


Which leads me to my question: the 700 and 750 interfaces have >maximum
data acquisition rates of 100 kHz, if I remember >correctly. I thought this
would be great for, e.g. sampling sounds >which could then be put through
fft to find high frequency >harmonics. In practice I've found that I can't
sample
faster than about 10 kHz, still with some problems. (the sampling >rate was
enough for what I wanted to do but worked only in short >bursts) Is the 100
kHz rate a purely digital data transfer rate, or >what? In what circs is
this maximum rate used?



I have had a few sampling rate problems, put mostly when I suspected
that I would be pushing the apparaturs. Just yesterday I was playing with a
Rube Goldberg type setup in which I had a force, a current, and a voltage
probe all connected and I found that I couldn't push the sampling rate above
200 samples per second without getting a "computer is not keeping up"
message

I also once had trouble when using the sound detector and the Science
Workshop software in oscilloscope mode to illustrate beats . Under some
circumstances I couldn't display multiple beats across the screen without
getting that same computer message; but I was always able to easily find
frequencies that gave convincing displays.

However, in each of these cases I suspect that the computer speed rather
than the Pasco interface itself was the biggest part of the problem.

Ed Schweber