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Parallax oscope software glitch? — Parallax Forums

Parallax oscope software glitch?

RitaChRitaCh Posts: 9
edited 2009-04-16 20:00 in General Discussion
It looks like there is a glitch either in soft of in the hardware of the scope. Say, i have 5V DC on the scope input. The scope shows it correctly in the 5, 2 and 1V ranges, but below that the reading suddenly jumps to about 2V. This happens on both channels, and i have newer version of the software (I'm not sure, but i believe it was the same with the old version).
Did anyone notice such thing before. Or it's a glitch of my scope only?

Thank you

Rita

Comments

  • $WMc%$WMc% Posts: 1,884
    edited 2009-04-15 02:33
    RitaCh

    What operating system are You using?

    I have had some problems with Vista and XP 64 on a few software applications. the Parallax Oscope is just one of them.

    I haven't had any voltage reading problems.

    One last thing. If Your using the Parallax Oscope with a laptop, Some times the power out to the USB port will be limited if on battery or if battery was low when hooked up to the charger.

    Sorry I can't give a definite answer.

    __________$WMc%________

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    The Truth is out there············································ BoogerWoods, FL. USA
  • RitaChRitaCh Posts: 9
    edited 2009-04-15 17:18
    OS is Win XP Pro 32bit. It's a desktop and oscope is connected through a powered USP hub.
    I'm pretty sure the truth is somewhere here on this forum [noparse];)[/noparse].
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2009-04-15 20:01
    Hello,

    The Scope does use a different internal op-amp for different ranges depending on the current setting. As I recall from 1V up it uses one and below 1V uses another. However I don’t recall such an issue being reported previously. I will contact our Tech Support Dept. and have them test both versions of the software to see if they can duplicate what you’re seeing. Take care.

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    Chris Savage
    Parallax Engineering
  • $WMc%$WMc% Posts: 1,884
    edited 2009-04-16 01:15
    RitaCh

    My Parallax Oscope runs flawlessly on My XPhome32bit machine(tower) and on My XPpro32bit laptop.
    It was the best $130 bucks I spent in a long time on a tool ,I use it all the time.

    Its XP64 and Vista(64bit) that I've had problems with USB drivers.


    ________$WMc%__________

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    The Truth is out there············································ BoogerWoods, FL. USA
  • RitaChRitaCh Posts: 9
    edited 2009-04-16 12:45
    Thank you, Chris. Yes, this is what i thought - that higher and lower voltages being handled differently to extend input's dynamic range. I have this suspicion that on lower ranges signal is just being "truncated" when it's above 2V threshold, by a zener in the input circuit, for example. But I need to confirm that. I'll try to experiment with this a bit more tonight. Please, let me know if you need any additional info to diagnose this issue.

    Regards,
    Rita
  • RitaChRitaCh Posts: 9
    edited 2009-04-16 12:48
    and btw, Chris, could you have a look at this thread as well, please? http://forums.parallax.com/forums/default.aspx?f=15&m=343638
    maybe you can find this out through your tech support as well?
    Thank you
    Rita
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2009-04-16 19:24
    As I suspected the lower ranges are limited to 4V peak-peak by the input amplifier, so you will only get from -2V through +2V range when selecting <1V range for voltage. I hope this helps. Take care.

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    Chris Savage
    Parallax Engineering
  • RitaChRitaCh Posts: 9
    edited 2009-04-16 20:00
    Thank you, Chris! That's what I thought.
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