Question about dataloggers???

Discussion in 'General Electronics Chat' started by cds333, Apr 29, 2010.

  1. cds333

    Thread Starter Member

    Nov 5, 2007
    16
    0
    I know this is pretty basic but please bear with me...

    So lets say I want to capture digital signals, and since my oscilloscope is a cheap analog POS, it is useless for this purpose.

    Lets say I want to visually see the data being transferred from a PC keyboard, for example, when I hit a key; or maybe I want to see whats being transferred through a USB port from some kind of USB peripheral to my computer, or perhaps I just want to stick some probes into a circuit, so I can see what data is being sent to or from a random IC, then what kind of logger do I need, and how much can I expect to pay?...

    I assume what I need is called a datalogger, but I don't know what kind I would need... I was looking at the Omega website, and these two caught my eye:

    http://www.omega.com/ppt/pptsc.asp?ref=OM-DAQPRO-5300&ttID=OM-DAQPRO-5300

    http://www.omega.com/ppt/pptsc.asp?ref=OM-SQ2010&ttID=OM-SQ2010

    Now the first one doesn't specifically say anything about digital, but it does say "Frequency/Pulse Input", is that the same thing?

    The second one says it has 8 digital inputs, so I'm pretty sure it would work, but it is more expensive.

    Are the aforementioned the best tools to accomplish what I want to do, or could anyone recommend something better (or cheaper)?

    I have only basic electronics knowledge (mostly analog) and some PIC experience but nothing this advanced so any help would be much appreciated.
     
  2. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    If you want to actually "see" the data being transfered back and forth between devices, I would recommend something like the Intronix 34 Channel Logic Analyzer, this has built in interpreters that will interpret a certain protocol such as RS232, I2C, SPI, etc.... and for the price, it can be beat for what it can do, you can download the software and play with it a bit in demo mode... go here to check it out >>http://www.pctestinstruments.com/

    My .02

    B. Morse
     
  3. cds333

    Thread Starter Member

    Nov 5, 2007
    16
    0
    Thanks a lot for the info!

    I assume that thing does digital only right?
    It says it is 34 channel; does that mean I could hook up 34 probes to it and see 34 different readings?

    Whats the difference between a logic analyzer and a datalogger anyway?

    Also whattabout this thing:
    http://www.usbee.com/zx.html

    Thanks
     
  4. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    Yes, you can see a lot happening at once. Faster than you would ever need.

    download their software and use the demo... I think it is exactly what you want.

    The USBee is also like it, with fewer channels.
     
  5. cds333

    Thread Starter Member

    Nov 5, 2007
    16
    0
    So does that thing do analog? In the demo I see a sine wave (called +SINE_GROUP)... Is that a simulated input signal or some internal function?

    Also I assume that "H" and "L" mean "high" and "low", but what does "T" mean?

    Thanks
     
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  6. kingdano

    Member

    Apr 14, 2010
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    t means 'triggered' so it means that the device is registering a change of the logic level on that signal.

    i am not familiar with the sine group function there, but i do have a similar logic analyzer at work from intronix.


    edit: its the same analyzer - didnt know the website we got it from :)
     
  7. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    It simulates the sine from the wave. It will function as a analog waveform "viewer" but not an oscilliscope if you need high resolution.
     
  8. someonesdad

    Senior Member

    Jul 7, 2009
    1,585
    141
    If you wouldn't mind owning a boat anchor, you might be able to find an HP 16500 logic analyzer relatively cheap on ebay or elsewhere. They're large and heavy, but it it comes with the needed probes, cables, decoding modules and software, you'll get a pretty useful device. If I recall correctly, there were four or so slots in the back and you could stick in different modules, such as a digital scope, state modules, or timing modules. It was operated with a touch screen and a knob and was pleasant to use.
     
  9. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    If you have the money, get yourself an o'scope with logic analyzer. They are all in one packages, digital, and best of both worlds.
     
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