They generally are small, battery powered, portable, and equipped with a microprocessor, internal memory for data storage, and sensors.
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: Autonomous data loggers can be taken to diverse locations that cannot easily support fixed temperature monitoring equipment.
Temperature sensitive products such as foods,[4] pharmaceuticals,[5] and some chemicals are often monitored during shipment and logistics operations.
Exposure to temperatures outside of an acceptable range, for a critical time period, can degrade the product or shorten shelf life.
Battery-powered, formerly mechanical, the data logger is today an electronic device that can be programmed to record individual values over periods of a few hours to several months.
Placement of data loggers and sensors is critical: Studies have shown that temperatures inside a truck or intermodal container are strongly affected by proximity to exterior walls and roof and to locations on the lading.