CCST Communications & Networking in Control Systems Flashcards

Which industrial communication protocol uses a token-passing bus architecture and is commonly found in legacy process control systems?

Answer: PROFIBUS DP

PROFIBUS DP uses a token-passing bus architecture that allows deterministic communication in process automation environments.

What is the primary purpose of the HART (Highway Addressable Remote Transducer) protocol in process control?

Answer: Simultaneous analog and digital communication over the same two-wire loop

HART overlays digital signals on a standard 4–20 mA analog loop, enabling simultaneous analog process variable transmission and digital diagnostics.

In an industrial control network, what does the term 'determinism' refer to?

Answer: The guarantee that messages are delivered within a defined, predictable time frame

Determinism in industrial networks means that message delivery times are bounded and predictable, which is critical for real-time control.

Which OSI model layer is responsible for defining the electrical and physical characteristics of a fieldbus network cable?

Answer: Physical layer

The OSI Physical layer defines cable types, connectors, signal voltages, and bit-rate specifications for network media.

What is the maximum number of devices that can be addressed on a single HART multidrop network segment?

Answer: 15

HART multidrop mode supports up to 15 devices on a single segment, with each device set to a unique polling address from 1–15.

A control system technician needs to isolate a segment of an industrial Ethernet network for troubleshooting. Which device is used to create logical network segments at Layer 2?

Answer: Managed switch

A managed switch operates at OSI Layer 2 and can create VLANs and manage traffic to logically isolate network segments.