Statistical Logging and Battery Life

You can configure HOBO UX100 series and some HOBO UX120 series loggers to calculate maximum, minimum, average, and standard deviation statistics for all enabled sensors during logging at each logging interval based on samples taken at a rate you specify. This will result in up to four additional series per sensor that record the following information at each logging interval:

  • The maximum, or highest, sampled value,
  • The minimum, or lowest, sampled value,
  • An average of all sampled values, and
  • The standard deviation from the average for all sampled values.

For example, let’s say both the temperature and RH sensors have been enabled, the logging interval is set to 5 minutes, and the sampling interval is set to 30 seconds (with maximum, minimum, average, and standard deviation all enabled). Once logging begins, the logger will measure and record the actual temperature and RH sensor values every 5 minutes. In addition, the logger will take a temperature and RH sample every 30 seconds and temporarily store them in memory. The logger will then calculate the maximum, minimum, average, and standard deviation using the samples gathered over the previous 5-minute period and log the resulting value(s). When reading out the logger, this would result in: 10 data series (not including any derived series, such as dew point): two sensor series (with temperature and RH data logged every 5 minutes); plus eight maximum, minimum, average, and standard deviation series (four for temperature and four for RH with values calculated and logged every 5 minutes based on the 30-second sampling).

Note: If an aggressive statistcal sampling is selected, this can greatly reduce your battery life!

Onset loggers are designed to conserve power by "going to sleep" in between logging intervals. When Statistics are enabled, the logger must "wake up" to do a sample in between these intervals (A 1-second sampling interval basically means the logger is "ON" all the time!!!)

Be careful when logging statistics. For most indoor applications, conditions normally do not change that quickly so aggressive sampling may not be required for your project.

If you need to sample at a fast rate, be sure to change your batteries more regularly!

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