From OpenSCADAWiki
To account the features of different data acquisition devices, as well as the different mechanisms of interaction, in OpenSCADA the modular subsystem "Data acquisition" is provided. The module of the subsystem is the driver for interfacing with a data source of specific type. Each module can contain the configuration of several devices of this type as controller objects. The general scheme of objects of "Data acquisition" subsystem is shown in Figure 1.