Distributed Control Systems (DCS) — MCQs – EE

1. The primary purpose of a Distributed Control System (DCS) is to:
(A) Centralize control at one point
(B) Distribute control tasks across multiple controllers
(C) Eliminate control loops
(D) Replace field instruments

2. A DCS is mainly used in:
(A) Small, standalone systems
(B) Large, continuous industrial processes
(C) Digital communication systems
(D) Office automation

3. In a DCS, control functions are typically performed by:
(A) Field devices only
(B) Local control units (LCUs) or controllers
(C) The central computer only
(D) PLCs in all cases

4. The main advantage of DCS over centralized control is:
(A) Higher computational speed
(B) Increased reliability and fault tolerance
(C) Lower cost of sensors
(D) Simplified wiring only

5. The operator interface in a DCS is provided by:
(A) Local control units
(B) Human Machine Interface (HMI)
(C) Remote terminal units
(D) Field transmitters

6. In a DCS architecture, the control room mainly contains:
(A) Field instruments
(B) Operator consoles and servers
(C) Control valves
(D) Transmitters

7. The communication between different control units in DCS occurs through:
(A) Pneumatic lines
(B) Data communication networks
(C) Manual signals
(D) Optical sensors only

8. The basic building block of a DCS is:
(A) Fieldbus
(B) Controller
(C) Central processor
(D) Server

9. In a DCS, the field control station (FCS) performs:
(A) Local process control and data acquisition
(B) Alarm display
(C) Trend plotting only
(D) Communication with operator only

10. The redundancy feature in DCS ensures:
(A) Backup control in case of a controller failure
(B) Data duplication for all variables
(C) Multiple displays for operators
(D) Manual override always available

11. The control strategy in DCS is usually implemented through:
(A) Relay logic
(B) Function blocks or software modules
(C) Analog circuits
(D) Hardware switches

12. DCS is most suitable for:
(A) Discrete manufacturing
(B) Continuous process industries like oil refineries
(C) Office management
(D) Home automation

13. The communication network in a DCS is often referred to as:
(A) Bus
(B) Ladder
(C) Star
(D) Matrix

14. The main function of the operator station in DCS is to:
(A) Control valves directly
(B) Monitor, supervise, and adjust control parameters
(C) Perform local control
(D) Send field data to transmitters

15. DCS systems are typically designed with:
(A) Hierarchical structure
(B) Flat structure
(C) Random structure
(D) Centralized structure

16. In DCS, data acquisition is primarily done at:
(A) The central control room
(B) Field control stations
(C) HMI level
(D) Historian server

17. One major advantage of DCS over PLC systems is:
(A) Better handling of continuous process control
(B) Lower programming complexity
(C) Smaller size
(D) Higher voltage operation

18. The HMI in DCS is used for:
(A) Viewing process data and alarms
(B) Controlling motor speed directly
(C) Performing signal conditioning
(D) Communicating with field transmitters

19. The engineering workstation (EWS) in DCS is used for:
(A) Designing and configuring control strategies
(B) Data trending only
(C) Manual control
(D) Alarm monitoring only

20. The historian server in DCS:
(A) Stores process data for long-term analysis
(B) Controls field loops
(C) Operates control valves
(D) Generates setpoints

21. The redundant communication network in DCS is provided to:
(A) Avoid communication failure
(B) Increase data rate
(C) Simplify network topology
(D) Reduce cost

22. In a DCS, alarms are generated when:
(A) A variable exceeds its normal limit
(B) The operator requests a report
(C) Communication stops briefly
(D) Data is stored

23. A typical DCS network hierarchy includes:
(A) Field level, control level, and supervisory level
(B) Actuator, valve, and transmitter level
(C) Only one centralized level
(D) Manual and automatic level

24. The control algorithms in a DCS are implemented by:
(A) Field controllers
(B) HMIs
(C) Central server only
(D) Alarm stations

25. Fieldbus technology in DCS is used for:
(A) Digital communication between field devices and controllers
(B) Power transmission
(C) Mechanical control
(D) Emergency shutdown only

26. DCS can be integrated with:
(A) PLCs and SCADA systems
(B) Only sensors
(C) Manual systems
(D) None of these

27. The primary advantage of modular design in DCS is:
(A) Easy expansion and maintenance
(B) Reduced communication
(C) Higher power usage
(D) Faster analog response

28. In DCS, controllers are generally located:
(A) Close to the process area
(B) In the operator console
(C) In the historian server
(D) At the cloud storage

29. The redundancy in DCS can be applied to:
(A) Controllers, communication, and power supplies
(B) Transmitters only
(C) Actuators only
(D) Display panels only

30. The primary difference between DCS and SCADA is that DCS:
(A) Focuses on closed-loop control
(B) Uses remote data acquisition only
(C) Operates without feedback
(D) Has no operator interface

31. DCS communication protocols include:
(A) Modbus, Profibus, Foundation Fieldbus
(B) HTTP and SMTP
(C) USB and HDMI
(D) ASCII and Unicode

32. The function of redundancy in a DCS is to:
(A) Maintain continuous operation in case of hardware failure
(B) Reduce operator workload
(C) Improve display quality
(D) Simplify process design

33. The local control units in DCS are responsible for:
(A) Executing control algorithms near the process
(B) Generating alarm reports
(C) Performing manual override
(D) Controlling operator console displays

34. Interfacing sensors and actuators with DCS controllers is done via:
(A) I/O modules
(B) Wireless routers
(C) Keyboard input
(D) Database software

35. The scalability of DCS means:
(A) It can be expanded with minimal configuration
(B) It cannot be modified
(C) It’s fixed in size
(D) It cannot be networked