The SCADA system is a centralized setup that closely monitors and controls various processes. Its software package is located on top of the hardware. There are 5 essential components in any SCADA system – human-machine interface (HMI), supervisory system, remote terminal units (RTU), programmable logic controllers (PLC) and communication infrastructure.
The HMI processes data and sends it to an operator for appropriate action. The operator then monitors and operates the system accordingly.
The RTUs connect the sensors and convert the analog signals to digital data. The digitized data is then sent to the supervisory system to be logged and stored in a database.
The supervisory system gathers the data and sends commands or operations to the process.
PLCs are the control interfaces for the field devices. They are more versatile in their functioning compared to process specific RTUs.
The communication infrastructure establishes the backbone of the entire system by enabling connectivity between all the different components. It is the communication infrastructure that eliminates the need for proximity and enables remote operation.