From OpenSCADAWiki
The module of the data acquisition provides an opportunity to gather the information from various devices by means of the protocol ModBus in all modes. Also, the module implements the functions of the horizontal redundancy, that is working in conjunction with the remote station of the same level. At the same time, the module of the protocol allows you to create and issue data by means of the protocol ModBus in various modes, and through interfaces that are supported by modules of the subsystem "Transports".