SCADA Systems and Architectures

Flashcards on SCADA systems, their architecture, components, and communication methods.

SCADA

Supervisory Control and Data Acquisition systems differ from distributed control systems by covering much larger geographic areas, while distributed control systems cover plant sites.

SCADA Communications

Can utilize a diverse range of wired and wireless media depending on factors like remoteness, available communications, infrastructure, polling frequency, and data rates.

Monolithic or Early SCADA Systems

Were independent systems without common network services, using a back-up mainframe for redundancy and limited to monitoring sensors and flagging alarm levels.

Distributed SCADA Systems

Share control functions across multiple systems connected by LAN, reducing cost and size, but lacked standardized network protocols leading to security concerns.

Networked SCADA Systems

Communicate using WAN systems over data lines or phone, using Ethernet or Fiber Optic Connections and PLCs for monitoring; pose security risks due to internet connectivity.

Internet of Things (IoT) SCADA Systems

Reduce infrastructure costs by using cloud computing, enabling easier maintenance, complex control algorithms, and improved security through open network protocols.

HMI

A local screen allowing an operator to observe and control the process, displaying status, alarms, and control screens, and communicating with the PLC but not directly with instrumentation.

Master Terminal Unit (MTU)

Acts as a server hosting control software, communicating with RTUs and PLCs over an ICS network; initiates communication, unlike RTUs which simply collect and store data.

SCADA System Architectures

Composed of five layers: Field devices, Field controllers, Local supervisory, Production control, and Main monitoring station, each with specific functions in data collection, control, and monitoring.

SCADA Communications Topologies

Include Point to Point, Point to Multipoint, Point to Point to Point, Multipoint to Point, and Multipoint to Multipoint, each offering different benefits in terms of cost and performance.

SCADA System Tasks

Data Acquisition, Data Communication, Information/Data Presentation, and Monitoring/Control, facilitated by sensors, RTUs, controllers, and communication networks.

SCADA System Components

Include: Server Infrastructure, Networks established with switch redundancy, routing tables and VLANs. Master Terminal Unit (MTU), Visualization and HMIs, Programmable Logic Controllers | PLCs.