The sensor can record a reading up to every hour if required.
With running detection mode turned off the sensor will simply wake up and store a reading at each interval.
With running detection mode turned on the sensor will being checking to see whether the machine is running; to do this the sensor takes a simplified reading every 1 or 5 minutes, if the machine isn't running then this continues. If the machine is running the sensor will take a full reading and store this, the sensor will then sleep for the set log frequency. Once this sleep is over the process of checking for running starts again.