A supervisory control and data acquisition (SCADA) system is made up of hardware, software and network components that enable both remote and local supervision of equipment in industrial processes.
Before the introduction of SCADA, factory floor personnel had to monitor, log, and control manufacturing processes and equipment using control panels with switches, pushbuttons and dials for analog signals. Because of these manual processes, the personnel’s presence on-site was mandatory and the lead time to response was high.
SCADA was integral to the manufacturing environment during the third industrial revolution by using data gathered from equipment and processes to visualize manufacturing activity. SCADA operates in level 2 of the ISA 95 architecture connecting field automation equipment to manufacturing operation management solutions. The SCADA software aggregates data from programmable logic controllers (PLC) and microcontrollers. Controllers are then used to picture the manufacturing process through a human-machine interface (HMI), hence giving visibility and control to the operator.
Here is a brief overview of the components of a SCADA system and their respective functions.
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.
SCADA systems offer a multitude of benefits to manufacturers and organizations that use them to optimize various production processes. The most common benefits of SCADA systems are listed here:
SCADA systems have been around for over 40 years and have helped industries monitor and manage their processes and applications. It has and continues to play a pivotal role in improving efficiencies and minimizing costs. However, in the era of industry 4.0, questions about the relevance of SCADA arise with the changing times. While SCADA continues to hold data within the confines of the factory floor, IoT processes data and offers insights beyond the bounds of proximity. These insights lead to the evolution of newer business models around it. However, viewing IoT as a technology implemented on top of SCADA opens avenues for scalability, advanced analytics, and improved interoperability.
