Types of SCADA System to Know About

Without their Supervisory Control And Data Acquisition (SCADA) system, most modern industrial, utility, or processing plants would cease to function. This computer-based control scheme allows one operator or a few operators to oversee various activities.

FREMONT, CA: The majority of modern manufacturing, utility, and processing plants cannot function without their Supervisory Control And Data Acquisition (SCADA) system, a computerized control scheme that enables a single operator or small group of operators to supervise several processes. SCADA is a multiplier of force. By utilizing distributed electronic controls and sensors to handle batch or repeated tasks, SCADA notifies the operator if something requires attention or exceeds predetermined parameters. Multiple SCADA system types are in use. Generational differences predominate. Early systems differ significantly from modern systems, as well as from modern systems themselves. Modern SCADA systems often combine a combination of hardware and software.

Early or Monolithic SCADA systems

The original SCADA systems contained all functions on a single computer, often a mainframe. The majority of early SCADA activities were restricted to monitoring sensors and identifying operations that exceeded programmed alarm thresholds. These systems were vendor-specific and typically restricted to a single plant or location. Similar to the software, SCADA gear from one vendor was rarely compatible with that of another.

Distributed SCADA Systems

Later, SCADA systems became known as Distributed systems because they frequently shared control functions across a network of smaller (mostly PC) computers (LAN). Using LAN, these individual stations communicated real-time data and often performed tiny control chores in addition to notifying operators of potential problems and alarm activations.

Networked SCADA systems

Typically, modern SCADA systems are networked. They communicate via Wide Area Network (WAN) systems, phone or data lines, and frequently send data between nodes over Ethernet or Fiber optic links. Networked SCADA systems rely heavily on Programmable Logic Controllers (PLC) to monitor and change regular processes, alerting Operators only when critical choices are necessary.

In contrast to early SCADA systems, which relied mostly on vendor-specific software and occasionally hardware, modern systems are based on software designed for general use. PLC and other sub-unit vendors have standardized communications and other protocols. The hardware tends to be more interchangeable, allowing the customer to choose the best component for their needs rather than being limited to a single vendor's product line.

While early SCADA systems were restricted to single-building or single-site networks, many modern SCADA systems are connected to the Internet, introducing security issues not present in older or "sealed" systems.