And with the log file data available, visualizing energy consumption with timestamp is easy.
Files and scripts of log files are avaiable on this project's GitHub
With data logged, we can hook up intested's applicant. For a new destop with two monitors (LCD, 23"), a light use is about 100W. When monitors were on stanby, the computer is still running and consumming about 50W.
More importantly, we would like to compare with an official meter from the service provider. Here is a chart showing actually points and a linear regression line.
We can adjust the difference in starting numbers. The two line is matched almost perfpectly with a r2 = 0.999.