The DS1921G Thermochron? iButton? is a rugged, selfsufficient
system that measures temperature and records
the result in a protected memory section. The recording
is done at a user-defined rate, both as a direct storage of
temperature values as well as in the form of a histogram.
Up to 2048 temperature values taken at equidistant intervals
ranging from 1 to 255min can be stored. The histogram
provides 63 data bins with a resolution of 2.0°C.
If the temperature leaves a user-programmable range,
the DS1921G also records when this happened, for how
long the temperature stayed outside the permitted range,
and if the temperature was too high or too low. An additional
512 bytes of read/write nonvolatile (NV) memory
allows storing information pertaining to the object to
which the DS1921G is associated.