From OpenSCADAWiki
The "Logical level" concept is based on the template parameters, for which, in the subsystem "Data acquisition", the container of template libraries is provided (Fig.1). Each library contains templates of parameters that can be used by the modules of the subsystem "Data acquisition" for implementation of parameters based on the templates. The OpenSCADA modules, which use the templates in their work, are:
- LogicLev — module of implementation the classical conception of "Logic Level" .
- ModBus — module of accessing data sources through the family of "ModBus" protocols. Besides of the parameter type of the direct description the registers list it also supports the logical type, where the "ModBus" registers described in links of the template.
- Siemens — data acquisition module for Siemens controllers of the series S7. Thanks to the high flexibility and functionality of the controllers in this series, which allows for the formation of complex data types of diverse structure, all parameters of this module work on templates.
- OPC-UA — module of accessing data sources through the "OPC-UA" protocol. Besides of the parameter type of the direct description the nodes list it also supports the logical type, where the "OPC-UA" nodes described in links of the template.