A temperature data logger, also called temperature monitor, is a portable measurement instrument that is capable of
autonomously recording temperature over a defined period of time. The digital
data can be retrieved, viewed and evaluated after it has been recorded. A data logger
is commonly used to monitor shipments in a cold chain
and to gather temperature. It is to ensure that the temperature provided are according to the specification required.
A variety of constructions are
available. Most have an internal thermistor
or thermocouple
or can be connected to external sources. Sampling and measurement are
periodically taken and digitally stored. Some have a built in display of data
or out-of-tolerance warnings. Data retrieval can be
by cable, RFID, wireless systems, etc. They generally are small, battery
powered, portable, and equipped with a microprocessor, internal memory for data
storage, and sensors. Some data loggers interface with personal computers or
smart phones for set-up, control, and analysis.
Some include other sensors
such as relative humidity, wind, light, etc. Others may record input from GPS
devices.
Depending on the use,
governing quality management systems sometimes
require calibration
to national standards and compliance with formal verification and validation protocols[1]
Choices of temperature data
loggers can be based on many factors, such as:
- Cost
- Reusability
- Battery life
- Ease of use; set-up, readability, download data, analysis, etc.
- Temperature range
- Accuracy and precision - degree of
agreement of recorded temperature with actual
- Response time – the time required to measure 63.2% of the total
difference between its initial and final temperature when subjected to a
step function change in temperature; other points such as 90% are also
used.[2]
- shock and vibration
resistance
- Water resistance – humidity, condensation, etc.
- Size, weight, mounting
- Certifications, calibrations, etc.
- Software
