An IoT data logger includes a log function. This enables you to collect big data sets from the sensors with minimum battery consumption, as the logger keeps sensor data in logs instead of transmitting it to the server immediately. The log function is also important in the case of connectivity failure or if the data logger is moved into an area without coverage. In these events, data is logged instead of lost. When GSM coverage is re-obtained, it will transmit the data it has collected while having been without coverage on its scheduled time of transmissions. Logs can contain data of position, date, time, and sensor data like temperature and shock etc. Thereby it can provide complete data visibility and insights for documentation and knowledge of any incidences. For example, an advanced log function will enable you to follow a breadcrumbs route of a shipment. It will also enable you to track the temperature of a shipment to see if there have been any fluctuations during transport. In the latter case, a data logger without a log function on a freight ship would only be able to transmit a temperature right before leaving data coverage and not again until reaching harbor. With the log function, it has collected data during the whole trip. This is crucial in cold chain cases where the temperature in food containers must not exceed a certain temperature limit at any point. Now you would know if temperature control has failed during transport and for how long-time limits have been exceeded.