2.1. Data Types, Data Model & Functionality

The following sections describe the main functionalities of the Eclipse SCADA system. Most of these functionalities are not specific to Eclipse SCADA, but to SCADA systems in general. Also is there no sharp line between other technologies like M2M or IoT systems which also offer connectivity with other devices.

The Eclipse SCADA system re-used some data types and structures at many interfaces. So they deserve some extra explanation.

The main purpose of the DA modules is to acquire data from various data sources and offer them other modules for processing or visualization. The basic idea is that the data is provided in simple scalar values instead of complex data structures. So instead of having a complex data structure for a component (e.g. a meteo station) that has wind speed, wind direction and several other values, there are simply 3 (or possibly more) analog values. The structure is created by the namespace instead of data structures.

The advantage of this approach is that all values can be treated equally when they are processed. It also simplifies the process of subscribing to values.

For example if one application is only interested in the wind speed it will only subscribe to that value. There is no need to get the full data structure or to split up that structure.

On the other hand there are functionalities like the level alarm . It monitors a value, and if it exceeds a defined value range, it will create an alarm. Now since that functionally only works on a single analog value, it can work on data coming from any system, describe any state. No matter if it is wind speed, disk usage or warp core intermix ratio. It always works the same way.

The main purpose of the AE module is to monitor and evaluate the data acquired by DA. A set of rules can be specified for each item or for a group of items, which will be evaluated to ok or not ok. Changes to these states will be transformed into events, which are logged to a persistent storage.

While the AE module stores events (log entries) the HD system is for storing analog values over a long period of time. Data which is provided by the DA modules can be persisted and queried to/from a time series database.