Deck 14: Process Control,network Systems and Scada

Question 1

The deadband of a controller is the range above and below the set point that will not produce a change in the control action.

Answer 1

True

Question 2

A continuous process involves the flow of product material from one section of the process to another.

Answer 2

True

Question 3

In a closed-loop control system,the controller receives no information concerning the status of the process.

Answer 3

False

Question 4

A sensor could be classified as a type of controller.

Question 5

Closed-loop control systems contain a feedback element.

Question 6

Distributive control systems are network based.

Question 7

Sensors convert physical information into electric signals.

Question 8

Distributive control systems (DCS)use one controller for all the processing tasks.

Question 9

HMI graphic terminal software is used to create and animate objects related to the process on the screen.

Question 10

In a batch process,a set amount of product is received and then some operation is performed on the product.

Question 11

Trend values of graphic HMI terminals display information on process variables over a period of time.

Question 12

Actuators convert physical information into electrical signals.

Question 13

Signal conditioning involves converting input and output signs into a usable form.

Question 14

With on/off control,the measured variable will oscillate around the set point.

Question 15

An open-loop system is one in which the output of a process affects the input control signal.

Question 16

A pushbutton switch could be classified as a type of human-machine interface.

Question 17

Centralized control involves two or more computers communicating with each other to accomplish the complete control task.

Question 18

On/off control eliminates hunting.

Question 19

One disadvantage of centralized control is that,if the main controller fails,the whole process is stopped.

Question 20

Distributive control is used when several machines are controlled by one controller.

Question 21

Each device connected on a network is known as a repeater.

Question 22

Two types of communications links found in PLC systems are point-to-point and network.

Question 23

Proportioning action occurs within a proportional band around the set-point.

Question 24

A fuzzy logic PID controller changes the amount of output signal in a mathematically specified way.

Question 25

The operation of a proportional controller leads to a process deviation known as offset.

Question 26

Proportional controllers are designed to eliminate the cycling associated with on/off control.

Question 27

PLC networks are not allowed to communicate via wireless radio wave systems.

Question 28

Derivative action responds to the magnitude at which the error signal is changing.

Question 29

PLCs can be fitted with I/O modules that produce PID control,or may have sufficient mathematical functions that allow PID control to be carried out.

Question 30

Deadband is used in controllers to prevent repeated activation-deactivation cycles.

Question 31

A network node is a device that amplifies a signal to its original strength.

Question 32

A PID controller reduces the system error to zero faster than any other type of controller.

Question 33

PLCs can be used for both linear and rotary motion control applications.

Question 34

Time proportioning control varies the ratio of on time to off time.

Question 35

A robot arm is basically a series of mechanical links driven by solenoids.

Question 36

The feedback input determines the desired operating point for a process.

Question 37

On/off control permits analog control of the final control element.

Question 38

A PID loop is normally tested by making an abrupt change to the setpoint and observing the controller's response rate.

Question 39

A PID controller must be factory-tuned to each process being controlled.

Question 40

Integral action eliminates steady-state error.

Question 41

Serial transmission is recommended for distances of over 50 feet.

Question 42

The field devices connected to a DeviceNet network contain intelligence in the form of a microprocessor.

Question 43

Full -duplex transmission allows the transmission of data in both directions simultaneously.

Question 44

Peer-to-peer networks use the token passing media access method.

Question 45

A network switch or hub is required for network star topology.

Question 46

Network protocol refers to the physical layout of devices on a network.

Question 47

In master/salve polling protocol network direct communications among slaves is possible.

Question 48

Bus topology is a network configuration in which all stations are connected in series.

Question 49

EtherNet/IP is an open communications network based on the same protocol that is used with DeviceNet and ControlNet.

Question 50

Ethernet networks use a collision detection based access control scheme.

Question 51

Gateways make communication possible between different protocols.

Question 52

Bandwidth refers to the data rate of a network expressed in terms of bits per second.

Question 53

In serial transmission data is transferred one bit at a time.

Question 54

The access method refers to the manner in which a PLC accesses a bus network to transmit information.

Question 55

Network topology defines how data are arranged and coded for transmission on a network.

Question 56

ControlNet is an open high speed network that is highly deterministic and repeatable.

Question 57

DeviceNet is a proprietary high speed device level network.

Question 58

Device bus networks interface with devices such as pushbuttons.

Question 59

In a token passing based network,a node can transmit data on the network at all times.

Question 60

The Allen-Bradley data highway network is an open communications network.

Question 61

HMIs allow operators to ____ the application.

A)control
B)monitor
C)diagnose
D)all of these

Question 62

Which of the following devices could be classified as a sensor?

A)Thermistor
B)Relay
C)Solenoid
D)All of these

Question 63

With an on/off controller:

A)the output is either completely on or completely off.
B)a positive deviation of the process variable from its set point causes the controller to shut the control element off.
C)a negative deviation of the process variable from its set point causes the controller to turn the control element on.
D)all of these.

Question 64

The integral action responds to:

A)the size and time duration of the error signal.
B)the speed at which the error signal is changing.
C)proportional bandwidth.
D)proportional gain.

Question 65

Both Modbus and Fieldbus are serial communication protocols.

Question 66

Which of the following devices could be classified as an actuator?

A)Control valve
B)Electric brake
C)Servo motor
D)All of these

Question 67

In general,compared to an open-loop system,a closed-loop is:

A)more accurate.
B)more complex.
C)more expensive.
D)all of these.

Question 68

A closed loop control system measures the ____ output of the process compares it to the ____ output.

A)actual,desired
B)no-load,full-load
C)operating,non-operating
D)final,initial

Question 69

A proportional controller:

A)is designed to eliminate the cycling associated with on/off control.
B)allows the final control element to take intermediate positions between on and off.
C)permits analog control of the final control element.
D)all of these.

Question 70

A SCADA system usually refers to a system that coordinates,but does not control processes in real time.

Question 71

A closed-loop control system:

A)requires less power to operate.
B)does not require a feedback signal from the process.
C)uses a feedback signal from the process.
D)requires more power to operate.

Question 72

Time proportioning control refers to:

A)linear movement of the final control element.
B)varying the ratio of on time to off of the final control element.
C)the integral action of a controller.
D)the derivative action of a controller.

Question 73

A distributive control system (DCS):

A)permits the distribution of the processing task among several controllers.
B)always utilizes a single large computer.
C)will stop the whole process if one control element fails.
D)is the least flexible type of control system.

Question 74

Which of these controller types provides the fastest response to a system error?

A)PID
B)On/off
C)Proportional plus integral
D)Proportional plus derivative

Question 75

The derivative action responds to:

A)the size and time duration of the error signal.
B)the speed at which the error signal is changing.
C)proportional bandwidth.
D)proportional gain.

Question 76

A continuous process is:

A)one that never shuts down.
B)used only for simple tasks.
C)one in which raw materials enter one end of the system and the finished product comes out the other end.
D)used only with computers.

Question 77

Components of a control system may include:

A)sensors.
B)actuators.
C)Human-Machine Interface (HMI).
D)all of these.

Question 78

The set point for a control system refers to:

A)the input that determines the operating point for the process.
B)a process variable that is monitored continually.
C)a process error that is uncontrolled.
D)all of these.

Question 79

Assume two ingredients are added together,processed,and then stored.This would be an example of a(an):

A)batch process.
B)continuous process.
C)individual product-producing process.
D)discrete product-producing process.

Question 80

The error signal in a closed-loop control system is:

A)always a positive value.
B)always a negative value.
C)the difference between the set point and feedback signal.
D)the sum of the set point and feedback signal.