SYSTEM INTERFACE

SCADA SYSTEMS

SCADA systems are designed to collect and transfer data to a central location, which then displays the data to the operator. The operator can then monitor and control the system from the central location in real time. SCADA systems are generally constructed to be fault-tolerant, meaning it will continue operating in the event of a failure and has redundancy built into the system. Typical hardware for a SCADA system includes:

Control server: Located in a control center, the control server stores and processes data from Remote Terminal Units (RTU).

Communications Equipment: The hardware allows communication between the control server and RTU or PLC and the software tells the system what it needs to monitor, the parameters, and responses for values outside of the parameters. Examples of the hardware include radio, telephone line, cable, or satellite.

Intelligent Electronic Device (IED): Communicates with the control server to gather and relay data.

Remote Terminal Unit (RTU): Controls local processes. Often times will actively sample the IED to gather data to send to the control server.

Programmable Logic Controller (PLC): Controls local processes

Geographically Distributed Field Sites: Consisting of RTU and PLC. The field sites are responsible for controlling actuators and monitoring sensors.

DISTRIBUTED CONTROL SYSTEMS

Distributed Control Systems (DCS) are ICS that are used to control continuous processes. These processes generally require regulation of process parameters such as temperature, level, and flow control. Proportional, Integral, and Derivative (PID) algorithms are executed by the system controllers to accomplish this process regulation.

The typical hardware that comprises a DCS are as follows:

Engineering Workstation
Process Historian
Operator Workstation
Controllers
Input / Output Interfaces
Network Hardware

DISTRIBUTED CONTROL SYSTEMS

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