From OpenSCADAWiki
Archiving-history and Alarms
Q: How is the value of archiving cycles determined?
Re: Archiving is an independent task from the controllers and their parameters, and it is executed by the modular subsystem "Archives-History". What and how to archive is determined personally for each attribute parameter. There are two archiving modes: passive and active. Passive archiving is determined by the cyclicity of obtaining data by the controller — the cycle of the data collection module. Active archiving is provided by the task of the archiving subsystem and regardless of the cycle and method of the data acquisition by the DAQ module.