Four things decide whether a recorder is useful: the measuring range, where the sensor sits, how the data leaves the device and how verification is kept up. EN 12830:2018 covers recorders for the transport, storage and distribution of temperature-sensitive goods between -80 °C and +85 °C and treats them as a whole system from sensor to software. Thermometers fall under EN 13485 and periodic verification under EN 13486. Compare the accuracy on the data sheet with your acceptance criterion; resolution and accuracy are different things.
Where the sensor measures
A single-sensor recorder tells the story of one point: near the door you see every opening but not the centre of the load. In an insulated container, measure the point that warms fastest and keep that point fixed across all records; if it moves, the curves cannot be compared.
Data and alarms
Open a sample file before buying: is there a timestamp, a sensor identity and readable values? A printer-equipped device hands over a signed printout at delivery; a wireless device collects data by itself but may feed a dashboard nobody watches. Write down who steps in after a deviation and by which procedure. A recorder does not cool, it writes down what happened; the fix sits in pre-cooling, plate count, door discipline and route order. Sensors can drift, so verification is not done once but periodically, following EN 13486.
