3 methods of monitoring temperature

Manual

To manually monitor temperature an employee is assigned to look
at the thermometer built into a refrigerator, freezer,
incubator, etc and to manually record the temperature on a
periodic basis; usually once every eight hours or one a day.

Mechanical

Temperature monitoring can be done mechanically with a chart
recorder or strip recorder. These instruments use a sensor to
collect temperature data and draw a line on a round paper chart
or on a long strip of paper. The chart is periodically changed
and filed to prove that the temperature was maintained within
certain limits or to trouble shoot a problem. The big
disadvantage of this method is the need to constantly replace
the chart. The pens also run out of ink and must be replaced
periodically.

Electronic

A newer method of temperature monitoring is using data loggers.
A data logger is an all-electronic instrument that is programmed
with a computer to collect temperature samples and store them in
RAM memory. At some later time the data is downloaded to the
computer and printed out or archived electronically. This method
eliminates the need for paper charts and pens but the
information is not available to the user until it is downloaded
to the computer.

A new device, the ThermaViewer overcomes the limitations of the
chart recorder and data logger. It samples data electronically
but it also displays the temperature as a chart on an LCD
display. It doesn't need computers, paper charts, pens or
maintenance. It is a much better solution to the temperature
monitoring needs of today.