Supervisory control and data acquisition (SCADA) 

is a control system architecture comprising computers, networked data communications and graphical user interfaces for high-level supervision of machines and processes. It also covers sensors and other devices, such as programmable logic controllers, which interface with process plant or machinery. The SCADA concept was developed to be a universal means of remote-access to a variety of local control modules, which could be from different manufacturers.

👉System Components: 

             A SCADA system usually consists of the following main elements:

👉Supervisory computers: 

 This is the core of the SCADA system, gathering data on the process and sending control commands to the field connected devices. It refers to the computer and software responsible for communicating with the field connection controllers, which are RTUs and PLCs, and includes the HMI software running on operator workstations.

👉Remote terminal units:

       These are connect to sensors and actuators in the process, and are networked to the supervisory      computer system.

👉Programmable logic controllers: 

These are connected to sensors and actuators in the process, and are networked to the supervisory system.

👉Communication infrastructure

This connects the supervisory computer system to the RTUs and PLCs, and may use industry standard or manufacturer proprietary protocols.

👉Human-machine interface

The human-machine interface (HMI) is the operator window of the supervisory system. It presents plant information to the operating personnel graphically in the form of mimic diagrams, which are a schematic representation of the plant being controlled.


Difference between DCS and SCADA: