Looking for some Software

Discussion in 'Electronics Resources' started by DC_Kid, May 20, 2009.

  1. DC_Kid

    Thread Starter Distinguished Member

    Feb 25, 2008
    638
    9
    i have a issue with my power company (residential). my sub station also feeds a local cement plant and they have BIG electric motors. my power sucks to say the least.

    i want to sample line voltage and capture it to a file. sample rate could be something like 5-10Hz and data is perhaps 8-9 bits wide.

    any freebie stuff out there that can do this? my APC RS UPS cant do it (pos UPS).

    thanks
     
    Last edited: May 20, 2009
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    You will need to use a transformer to step the voltage down to a safe level and isolate yourself from the line.

    With the level low enough, any of the freeware sound card oscilloscope apps will work, and give you 16 bit resolution.

    http://www.ehow.com/how_2278973_use-sound-card-as-oscilloscope.html

    Ideally, you would want to sample in synchrony with the line, but that requires a zero crossing detector and uC.

    Dataq has some data loggers that are quite inexpensive. The software is freeware.
    http://www.dataq.com/products/startkit/index.htm
     
  3. DC_Kid

    Thread Starter Distinguished Member

    Feb 25, 2008
    638
    9
    ah, thanks.

    and Dataq...... i am looking at some of there stuff for doing data logging for some of my automotive stuff........


    wont a step-down transformer dampen the voltage spikes some due to its inductive nature? how about a full bridge rectifier directly on the 120v and then stepped down with a resistor divider? i'd be watching dc at this point, but just as good for monitoring....
     
    Last edited: May 20, 2009
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Attaching to the power line is intrinsically unsafe. The circuitry is at line voltage, and always presents a lethal shock hazard. Even with a divider, the non-isolated voltage will fry your logger.

    You will lose no significant data with a transformer. Consider that the power to your house is already going through a transformer on the power pole. Providing protection through the galvanic isolation of a transformer is necessary for safety. The voltage spikes will still show up.
     
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