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# Excel to make sense of CSV Power usage please

Questions:

This may be a bit of an odd one but hopefully shouldn’t be too hard for somebody with a little more knowledge than me. I’m currently using a tool called Joulemeter on my laptop. This program measures the power usage of my machine and saves the data as a CSV text file.

Here’s an example of the outputted readings:

``````TimeStamp (ms), Total Power (W), CPU (W), Monitor (W), Disk (W), Base (W), Application (W)
63465092415703,16.1,0.1,7.3,0.0,8.7,--
63465092416716,16.2,0.3,7.3,0.0,8.7,--
63465092417730,17.2,1.3,7.3,0.0,8.7,--
63465092418744,16.2,0.3,7.3,0.0,8.7,--
63465092419774,16.1,0.1,7.3,0.0,8.7,--
63465092420786,17.1,1.1,7.3,0.0,8.7,--
``````

So I’m mainly interested in the total power usage over a certain time, for example taking a reading over 8 hours and calculating the total power usage. If anyone can point me in the right direction with they I’d be very grateful. I was hoping to use Excel to display this information and finding a equation to display the timestamp is a formatted time and date is causing me particular trouble.

In order to display the `TimeStamp` as a date/time in Excel, you need to scale it into a `TimerSerial` number and then format it to display what you want.

To scale it you need to know what the base of your `TimeStamp` is (ie what date is a `TimeStamp` of `0`) and calculate the offset to Excel time.

Excel time can use either 1900 or 1904 as the base date. See this MS article.

To convert your TimeStamps, use the formula

``````=(+A1-Offset)/86400000
``````

where `Offset` is a calculated value to align the two systems. Eg if the `TimeStamp`‘s in your example data occured on 31 Jan 2012, `Offset = 59,927,882,400,000`.

To display the result as a date/time, format it to the precission you require,
eg `yyyy/mm/dd hh:mm:ss.000` will display date and time to the ms.

This would make the first line in your sample `2012/01/31 22:20:15.703`