Nor’easters, and storms in general have a much different quality these days. With modern weather forecasting, we all benefit from the early warnings, allowing us to prepare and hunker down. And that’s exactly what we did here at Etesian, as did everyone else in the Northeast. Storms being what they are, it gives me the opportunity to showcase our data logger by displaying some data from the day of the storm.
The data logging feature won’t be of any surprise to our wind power customers. They typically purchase the 201 readout equipped with this option. Keeping a record of the wind and in some instances the power produced by their wind turbine, allows them to track of the productivity of their wind turbines. We have a handful of other customers, who for a variety of reasons have wanted the data logging option as well.
201 with logger option – (USB flash drive plugged in middle bottom)
In brief, the data logger saves a file every day to a USB flash drive. These files are spreadsheet files, and they open directly in all modern spreadsheet programs (i.e. Excel) , and in many other types of analysis programs that deal with files referred to as “CSV files”. CSV refers to comma separated values, meaning a bunch of rows and columns of numbers, each number separated from the next with comma, and each line ending with a <CR> carriage return.
Every day the file saved to the USB flash drive is named that day’s date. So, in our example here, the file on the flash drive is 20150127.csv, as that date was the day of the storm and the most interesting data to look at. There are several was to put the data on your PC. Sneakernet is the easiest, if the logger is close by. Remove the USB flash drive from the logger, insert it in your PC and copy the files.
If your logger is remote, with the appropriate connectivity options, you can download the data with a telnet connection, or, with our newest logger containing a mobile (cell) network modem, the data is pushed to a cloud server every day and can be retrieved from the cloud to your PC.
Etesian’s newest PV powered cloud connected data logger
Let’s see what the storm looked like here in Western Massachusetts. First, our facility has a sensor outside measuring wind speed and temperature. Our logger does not have a precip detector connected to it, although there is no reason you couldn’t have one attached to it. All I can tell you about our snowfall is that unlike Central Massachusetts which got pummeled with about 3 feet of snow we got a respectable 10 inches, but nothing spectacular.
Our logger is next to my desk, so I copied the file on the USB drive to my PC and made a few plots of wind speed and direction. Just for fun, I looked up wind chill index definition, and then used the US formula of wind chill, did that calculation, and put that on the plot as well:
The data logger can be configured to average over just about any interval. Ours is set for 1 minutes averages, but it could have been set for 10 minutes, 1 hour, etc. In addition to the average for the interval, the data logger saves the maximum, the minimum, and the standard deviation (SD). SD is a measure of the variability during the interval. Also each interval, naturally, has a date and time stamp.
From the plot above, you can see that temperature (red trace) changes much more slowly than wind speed (blue trace). To calculate the wind chill (black trace), I used the maximum wind speed in the 1 minute averaging interval, as this would be a measure of the lowest perceived temperature. (Now – Friday 1/30, and the snow is coming down again!)