| When it comes to transporting products with a demand for high control specifications, Dave Ayres at Calibration Services provides some pointers on how to choose the right temperature logger
A data logger is an electronic recording instrument that monitors and reports various changes in environmental conditions over time. Data loggers can measure temperature, relative humidity, light intensity, voltage, pressure and shock, among other factors. Because they are stand-alone devices, data loggers are convenient to use in order to verify and control the quality of handling of any given product in storage, transit or distribution; and as they do not need to be linked to an external source of power, they can travel alongside a product while continuously recording the specific types of data that are required. Today, data loggers exist in a multitude of shapes and sizes, and are used everywhere from local businesses to the International Space Station.
To meet the growing demand for optimal cold chain management and the need for small data recording instruments, engineers have developed miniaturised, batterypowered data loggers equipped with a microprocessor, data storage system and sensor. Some data loggers provide the recorded data on a paper strip chart, while others can interface with a personal computer. Information can be simply downloaded, either by connecting the logger to a computer port and using specialised software to analyse, organise and print the data; or, in the case of wireless data loggers, by gaining remote access to the information. With wireless data loggers, you can monitor several locations at the same time, creating the equivalent of a data logging network.
Since data loggers monitor and record the environmental conditions of sensitive products in storage, transit and/or distribution, their use enables better control of cold chain quality. More specifically, data loggers provide the crucial information needed to ensure the safe handling, transport and storage of your products, and ascertain whether or not they have been kept in ideal conditions. EXTERNAL OR INTERNAL
Temperature loggers have the sensor either outside the case that holds the electronics, or inside the case. Figure 1 shows a plasticcased logger with an external sensor, and Figure 2 shows two robust metal-cased loggers of different sizes that have internal sensors. See ‘Advantages and disadvantages of external and internal sensors’ (page 90). Loggers are available that have internal and external sensors, allowing two temperatures to be measured simultaneously (such as when monitoring the temperatures in a fridge that has a freezer compartment). Figure 3 shows a twochannel logger. |
