SCADA System

A SCADA system (Supervisory Control And Data Acquisition) is implemented to monitor and supervise the tracking system.

A Supervisory Control and Data Acquisition (SCADA) System is used as an application development tool that enables system integrators to create sophisticated supervisory and control applications for a variety of technological domains, mainly in the industry field. The main feature of a SCADA system is its ability to communicate with control equipment in the field, through the PLC network. As the equipment is monitored and data is recorded, a SCADA application responds according to system logic requirements or operator requests.

In the developed supervisory system the SCADA application manages the overall system dynamics.

The Communication flux between the supervisory system and the control unit has been already illustrated in fig. 4.

Подпись: Fig. 4. Communication Strategy (SCADA - PLC Tracker)
Подпись: Fig. 5. Solar Park - PV panels

The SCADA PC is simultaneously a SCADA server and an internet server, as the implemented SCADA application is web enabled.

This application permits the selective access to the application depending on the user’s responsibility degree. In this paper we developed three user levels: Operators, Supervisors and Administrators. Among the main functionalities of a SCADA system there is the so called “Tag”.

A “Tag” is a defined variable that permits the change of information between the PLC network and the SCADA system, in a real-time environment. There are usually three types of Tags: PLC, Dummy and Compound. In the PLC Tags the PLC sets the variable values that are directly transferred to the Scada program. In the Dummy Tags the value is set by the user on the Scada interface and transferred to the PLC address. Finally Compound Tags are set by the Scada program, following the programmed operations.

3. Experimental Prototype