#4 Top 50 PLC and SCADA MCQ

Important 50 Multiple Choice Question based on PLC and SCADA

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Question 1: What is the full form of SCADA?

• Supervisory Control and Document Acquisition
• Supervisory Control and Data Acquisition
• Supervisory Column and Data Assessment
• Supervisory Column and Data Assessment

Answer: Supervisory Control and Data Acquisition

Question 2: DCS is a ______

• Distributed Control System
• Data Control System
• Data Column System
• Distributed Column System

Answer: Distributed Control System

Question 3 The control in SCADA is _____________

• Online control
• Direct control
• Supervisory control
• Automatic control

Answer: Supervisory control

Question 4 What is SCADA?

• Software
• Process
• System
• Hardware

Answer: Process

Question 5 Which of the following is not the component of a SCADA system?

• Database server
• I/O system
• PLC controller
• Sparger controller

Answer: Sparger controller

Question 6 When did the SCADA start?

• 1980s
• 1990s
• 1970s
• 1960s

Answer:1960s

Question 7 When did Windows become the world standard operating system?

• 1980s
• 1990s
• 1970s
• 1960s

Answer: 1990s

Question 8 How many levels are present in a complex SCADA system?

• 3 – levels
• 5 – levels
• 4 – levels
• 6 – levels

Answer: 4 – levels

Question 9 What is the full form of RAID

• Redundant Array of Independent Drives
• Redundant Array of Inexpensive Disks
• Redundant Array of Independent Disks
• All of the above

Answer: All of the above

Question 10 Which of the following is used for centralized network databases?

• RAID 2
• RAID 5
• RAID 1
• RAID 2

Answer: RAID 5

Question 11 Which of the following is the heart of a SCADA system?

• PLC
• HMI
• Alarm task
• I/O task

Answer: I/O task

Question 12 Which of the following is an example of the SCADA system?

• Emerson Delta V
• Honeywell Plant Scape
• Yokogawa CENTUM
• Power Studio Deluxe

Answer: Power Studio Deluxe

Question 13 What does NC stands for?

• New Configuration
• Normally Close
• Normal Classes
• Never Closing

Answer: Normally Close

Question 14 What is nominal DC voltage given to PLC?

• +10V
• +24V
• +5V
• +12V

Answer: +5V

Question 15 In which of the following is a PLC Programming tool.

• RS Logix 500
• RS view 32
• Keil u vision
• Core Vision AVR

Answer: RS Logix 500

Question 16 Among following which one is a PLC Programming Language

• Assembly
• Ladder Logic
• Java
• HTML

Answer: Ladder Logic

Question 17 In which of the following is the SCADA Software?

• OrCAD
• RS View32
• Keil u vision
• Porteous

Answer: RS View32

Question 18 Ladder logic programming consists primarily of:

• Virtual relay contacts and coils
• Logic gate symbols with connecting lines
• Function blocks with connecting lines
• Text-based code
• Hieroglyphics

Answer: Virtual relay contacts and coils

Question 19 Examine-on instruction in PLC language is symbolically represented by what shape?

• -] [-
• -( )-
• -]/[-
• None of these

Answer: -] [-

Question 20 The symbol -(L)- represent what instruction in the PLC language?

• OUT output unlatch instruction.
• OTL output latch instruction
• Examine off instruction.
• Output energize instruction

Answer: OTL output latch instruction

Question 21 In a PLC, the scan time refers to the amount of time in which …..

• The technician enters the program
• Timers and counters are indexed by
• One “rung” of ladder logic takes to complete
• The entire program takes to execute
• Transmitted data communications must finish

Answer: The entire program takes to execute

Question 22 The Boolean representation of this PLC program is:

• ABC + D
• C + (A + B)D
• C + D(A + B)
• ABC + BD
• C(AB + D)

Answer: C(AB + D)

Question 23 What is the color used for NO type switches?

• Red
• Green
• non of the above

Answer: non of the above

Question 24 To reset the time for a PLC what condition must be true?

• Reset rung of TON must be true.
• Reset rung of TON must be false.
• RST instruction with timer address must be true.
• RST instruction with associated timer address must be false

Answer: RST instruction with timer address must be true.

Question 25 The below rung would represent what Boolean equation?

• X • Y = Z
• X + Y = Z
• X • Y’ = Z
• None of the above.

Answer: X • Y’ = Z

Question 26 To increase the number of inputs and outputs of the PLC, one can use expansion modules.

• True.
• False.
• None of the above.

Answer: True.

Question 27 Solenoids, lamps, motors are connected to:

• Analog output.
• Digital output.
• Analog input.
• Digital input

Answer: Digital output.

Question 28 The _____ is moved toward the relay electromagnet when the relay is on.

• Armature
• Coil
• NO contact
• NC contact

Answer: Armature

Question 29 In a current sinking DC input module _____

• The current flows out of the input field device
• Requires that a AC sources be used with mechanical switches
• The current flows out of the input module
• Currents can flow in either direction at the input module

Answer: The current flows out of the input field device

Question 30 AC output field devices can interface to _____

• AC output modules
• Relay output modules
• Both a and b
• Neither a or b

Answer: Both a and b

Question 31 The difference between online and offline PLC programming is . . .

• Whether the PLC is running or stopped
• Whether the programming PC has internet connectivity
• The type of programming cable used
• Where the edited program resides
• The type of programmer used

Answer: Where the edited program resides

Question 32 In PLC programming, a retentive function is one that:

• Defaults to the “on” state
• Comes last in the program
• Defaults to the “off” state
• Cannot be edited or deleted
• Is not reset after a power cycle

Answer: Is not reset after a power cycle

Question 33 Normally open contacts are open when:

• When Input is not energized
• When the input is energized
• When input is higher than 20 volts
• None of these

Answer: When Input is not energized

Question 34 What is the largest integer number that a PLC counter function can reach if it uses a 16 bit register?

• 32,768
• 65,535
• 65,536
• 65,537
• 32,767

Answer: 65,535

Question 35 An NOR function implemented in ladder logic uses:

• Normally-closed contacts in series
• Normally-open contacts in series
• A single normally-closed contact
• Normally-open contacts in parallel
• Normally-closed contacts in parallel

Answer: Normally-closed contacts in series

Question 36 Which of the following instruction enables a jump to a subroutine?

• JMP
• SBR
• RET
• None of the above

Answer: JMP

Question 37 What are the features of SCADA?

• Control feature using a graphical representation
• Alarm Handling
• Security Management
• All of the above

Answer: All of the above

Question 38 Leading SCADA providers companies are.

• Siemens WinCC
• Microsoft
• TCS
• All of the above

Answer: Siemens WinCC

Question 39 What is Scripts in SCADA?

• Scripts are basically a form
• Scripts are basically a function
• Scripts are basically a facility
• Scripts are basically a favorite

Answer: Scripts are basically a function

Question 40 What is CIMPLICITY?

• SCADA package
• SCADA hardware
• SCADA software
• SCADA handler

Answer: SCADA package

Question 41 A good application for a timed interrupt in a PLC program would be:

• A communications function block
• A PID function block
• A math function block
• A motor start/stop rung
• A “watchdog” timer

Answer: A PID function block

Question 42 What is the full form of RTU ?

• Remote Terminate Unit
• Remote Terminal Unit
• Remote Translation Unit
• Remote Transfer Unit

Answer: Remote Terminal Unit

Question 43 What is the full form DDE?

• Dynamic Data Exchange
• Data Dynamic Exchange
• Domain Data Exchange
• Different Data Exchange

Answer: Dynamic Data Exchange

Question 44 What is the difference between SCADA and HMI.

• Both are same
• HMI is not related with SCADA
• HMI can be a part of SCADA but SCADA can’t be a part of HMI.
• SCADA is a part of HMI

Answer: HMI can be a part of SCADA but SCADA can’t be a part of HMI.

Question 45 What are the differences between PLC and SCADA?

• PLC is a hardware part while SCADA is a software part.
• PLC is a  software  part while SCADA is a hardware part.
• Both are hardware unit
• Both are software

Answer: PLC is a hardware part while SCADA is a software part.

Question 46 A PLC consists of

• Processor Unit
• Program Memory
• Input/output Section
• Display Device
• All of the above

Answer: All of the above

Question 47 An OR function implemented in ladder logic uses:

• Normally-closed contacts in series
• Normally-open contacts in series
• A single normally-closed contact
• Normally-open contacts in parallel
• Normally-closed contacts in parallel

Answer: Normally-open contacts in parallel

Question 48 What is the full form of NEMA ?

National Electronics Manufacturing Association
National Electrical Manufacturing Association 
National Electrotechnical Manufacturing Association 
National Electromechanical Manufacturing Association 

Answer: National Electrical Manufacturing Association 

Question 49 Which of the following is not element of SCADA:

• SCADA Communication
• Mono Terminal Units
• PLCs
• RTUs

Answer: Mono Terminal Units

Question 50 Identify the problem in this motor control PLC program:

• Coil
• Start contact
• Seal-in contact
• Stop contact
• Power source

Answer: Seal-in contact

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