Power, watt hours

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Power, watt hours

Post by Peteris77 » Fri Jun 24, 2011 7:40 pm

I drive motor with pwm from battery. Motor is working for about 0,5-1 second.i need to measure power or watt hours for this device. Can i do it with 2203 or i need some other device.

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Re: Power, watt hours

Post by Hitesh » Thu Jun 30, 2011 1:04 pm


For the benefit of others interested in similar applications, it is possible to use a PicoScope 2203 to do the above in conjunction with the PicoLog software.

You will require a voltage attenuator and a current clamp for the device you are measuring.

To setup PicoLog recorder to measure the voltage and current:
  • Within PicoLog Recorder, click File -> New Settings
  • Configure your recording method and sampling rate
  • Once the software has detected your PicoScope 2203, click OK.
  • When the PicoScope 2000 Measurements dialog appears, click 'Add...'
  • Setup Channel A for Voltage, applying any scaling if necessary
  • Setup Channel B for current - set the channel name, then click 'Options...' to set parameter formatting and scaling for graphs.
  • Click the 'Scaling' button and apply any scaling that you require for the current clamp (it will provide readings in millivolts which requires conversion). See also the attached screenshots.
  • You now have the option to create a Calculated Parameter to show the Power as the data is captured, or capture the data and process it afterwards to calculate Power in Watts and Watt hours.
  • To create a Calculated Parameter, click Settings -> Calculated Parameters in the PLW Recorder window
  • Click 'Add', then set the name and select the Input Parameters. The equation should be A * B (see the attached screenshot)
  • Click 'Options...' to set Units, and max/min values. Click 'OK', then 'OK' again.
  • Capture the data.
  • When complete, click the Spreadsheet icon - you can copy these values into Excel.
  • In the PLW Spreadsheet window, click the 'Tick' icon.
  • In the Spreadsheet Options dialog (see attached spreadsheet), click the 'Show individual readings' box then select the 'Average' tick box. If capturing data at 1 second intervals, enter 3600 in the time interval per row or 60 for 1 minute intervals to give you Watt-hours.
Best wishes,

Software Dev. Engineer

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Re: Power, watt hours

Post by Jeff » Tue Aug 02, 2011 10:15 am

Further to what Hitesh said, we also have an application note on measuring electrical power using PicoScope:

http://www.picotech.com/applications/ma ... lysis.html

You could adapt it to calculate watt-hours.

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