The datalogger, and its associated software, is the heart of any AWS. It is very often an electronic ‘black box’, hidden from view inside a display unit, but its specification defines both the capabilities and limitations of the AWS.

This chapter provides a non-technical guide to the various logger types, outlines their capabilities and limitations, and briefly covers a selection of popular AWS software. There are many different types of datalogger and software that can be used in meteorological measuring systems, ranging from basic pre-programmed fixed-sensor units to highly flexible, programmable devices which can link to a huge range of professional-quality sensors.

As with other components, it is advisable to match capabilities with requirements (and budget) carefully before purchasing any system. One of the biggest mistakes when purchasing a new AWS is under-specification. Very few budget systems can be expanded or upgraded, and therefore any required expansion – additional sensors, more detailed logging and so on – may necessitate the complete replacement of the original system. This has obvious implications for cost, inconvenience and temporary loss of record.