This function calculates the daily percentage of DC signal
recorded by the pm25_A
, pm25_B
, humidity
, and
temperature
channels. The data are flagged as DC signal when the
standard deviation of an hour of data from each channel equals zero.
The number of hours with a DC signal are summed over the day and a daily DC
percentage for each channel is returned.
This metric allows users to identify <U+201C>sticky values<U+201D>, or instances of a sensor
continuously logging the same value. A high percent DC value indicates the
likely occurrence of a <U+201C>sticky value<U+201D>, and a zero or low percent DC indicates
that the sensor is recording dynamic data.