Very much similar to the Data logger in theoretical concepts, event logger differ in regard by keeping logs of individual discrete events rather than the entire data over a span of certain period. These electronic devices are capable of storing events over a period of time, so they are rightfully termed as the "Event Logger".
Event loggers are used generally as counter mechanisms for appliances such as the rain gauge. It is used for small, independent projects as an appropriate substitution for the more advanced data loggers. Comparatively, these devices are relatively smaller and cheaper than the data loggers.