ATLAS loggers receive pulses from any type of resource meter (electricity, gas, water, steam, etc). The meters send a pulse signal each time a certain amount of the resource has been used, e.g. 5 kWh electricity or 10 Litres water.
The ATLAS loggers count the number of pulses they receive on each input channel into 15 or 30 minute periods.
The AtlasEVO system software collects this resource use information from the ATLAS loggers, stores it permanently, and provides comprehensive analysis & reporting tools to facilitate analysis of the data. For more see How do ATLAS Energy Management Systems work ?