Cellular Manufacturing

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chapter eight

Risk engineering of a networked

cellular manufacturing system

Networked cellular manufacturing systems (NCMSs) are typically found

in industrial plants where remote monitoring and control of systems is

necessary because of hazardous or inaccessible equipment locations. Such

facilities might include water treatment plants, wastewater treatment

plants, chemical engineering facilities, oil reneries, nuclear facilities,

and other such plants that are critical to the nation’s infrastructure. The

security assessment of NCMS is thus critical to protection from the rising

danger of cyber risks.

8.1 A networked cellular manufacturing system

A networked cellular manufacturing system is a congregation of inde-

pendent cellular manufacturing systems that measure and report in real

time both local and geographically remote distributed processes. It is a

combination of telemetry and data acquisition that enables a user to send

commands to distant facilities and collect data from them. Telemetry

is a technique used in transmitting and receiving data over a medium.

Data acquisition is a method of collecting data from the equipment being

controlled and monitored. NCMSs are usually networked, with at least

one controller, and one or more remote terminal units (RTUs) distributed

throughout the plant at necessary control points. An RTU can be com-

pared to an analog or digital converter. It can receive signals from sensors

at the control point, convert and send these signals to the controller, and

also receive signals back from the controller and convert the commands

so they can be understood by the actual control mechanisms. The funda-

mental components of the NCMS control system are

• Master terminal unit (MTU)

• Communication network (CN)

• Remote terminal unit (RTU)

The supervisory control and monitoring station, also called the master

terminal unit, consists of an engineering workstation, human– machine

interface, application servers, and communications router. The master