Question 1

The PLC recognizes only _________.

Accepted Answer

A)  push-buttons 
B)  pressure switches 
C)  open or closed contacts 
D)  float switches 
A)  push-buttons 
B)  pressure switches 
C)  open or closed contacts 
D)  float switches C

Question 2

A(n) _________is connected across the ac input to help eliminate any voltage spikes that may occur.

Accepted Answer

A)  rheostat 
B)  metal-oxide varistor 
C)  avalanche diode 
D)  gas tube 
A)  rheostat 
B)  metal-oxide varistor 
C)  avalanche diode 
D)  gas tube B

Question 3

What are the advantages and disadvantages of controlling output with small relays?

Accepted Answer

One method of controlling the output is with small relays. The CPU controls the relay coil. The contacts connect the load to the line. The advantage of this type of output module is that it is not sensitive to whether the voltage is ac or dc and can control 120- or 24-volt circuits. The disadvantage is that it does contain moving parts that can wear. In this instance, the CPU is isolated from the external circuit by a magnetic field instead of a light beam.

Question 4

The current rating of most outputs can range from 0.5 to about _________amperes, depending on the make of the controller and the type of output being used.

Accepted Answer

A)  one 
B)  two 
C)  three 
D)  five 
A)  one 
B)  two 
C)  three 
D)  five

Question 5

Electrical noise is such a problem in some installations that several manufacturers are using_________ instead of wires for connection to the I/O rack.

Accepted Answer

A)  transistors 
B)  coaxial cables 
C)  optical cables 
D)  radio signals 
A)  transistors 
B)  coaxial cables 
C)  optical cables 
D)  radio signals

Question 6

PLCs were first used by the_________ industry in the late 1960s.

Accepted Answer

A)  railroad 
B)  defense 
C)  automotive 
D)  steel 
A)  railroad 
B)  defense 
C)  automotive 
D)  steel

Question 7

The most popular way to isolate the CPU from the external circuit is through_________ .

Accepted Answer

A)  optical isolation 
B)  small relays 
C)  rheostats 
D)  bridge rectifiers 
A)  optical isolation 
B)  small relays 
C)  rheostats 
D)  bridge rectifiers

Question 8

The PLC is a special type of _________designed to perform a special function.

Accepted Answer

A)  die 
B)  motor 
C)  robotic arm 
D)  computer 
A)  die 
B)  motor 
C)  robotic arm 
D)  computer

Question 9

The_________ is used to program the CPU.

Accepted Answer

A)  I/O rack 
B)  power supply 
C)  tape deck 
D)  loading terminal 
A)  I/O rack 
B)  power supply 
C)  tape deck 
D)  loading terminal

Question 10

What are some potential problems you might face when grounding equipment?

Accepted Answer

Ground is generally thought of as being

Question 11

In the relay method of isolation, the CPU is isolated through the use of a(n) _________.

Accepted Answer

A)  LED 
B)  laser 
C)  electrostatic buildup 
D)  magnetic field 
A)  LED 
B)  laser 
C)  electrostatic buildup 
D)  magnetic field

Question 12

What are timers and counters?

Accepted Answer

Timers and counters are internal relays.

Question 13

Describe the power supply of the PLC.

Accepted Answer

The function of the power supply is to l

Question 14

An electronic device that is often used to help overcome the problem of induced noise is the_________ .

Accepted Answer

A)  float switch 
B)  LED 
C)  MOV 
D)  differential amplifier 
A)  float switch 
B)  LED 
C)  MOV 
D)  differential amplifier

Question 15

Highlighting a contact means that there is a_________ through that contact.

Accepted Answer

A)  complete circuit 
B)  short circuit 
C)  change of state 
D)  troubleshooting element 
A)  complete circuit 
B)  short circuit 
C)  change of state 
D)  troubleshooting element

Question 16

The_________ is used to connect the CPU to the load.

Accepted Answer

A)  opto-isolator 
B)  power supply 
C)  input module 
D)  output module 
A)  opto-isolator 
B)  power supply 
C)  input module 
D)  output module

Question 17

The actual logic of the control circuit is performed by_________ .

Accepted Answer

A)  physical relays 
B)  internal relays 
C)  contacts 
D)  RAM 
A)  physical relays 
B)  internal relays 
C)  contacts 
D)  RAM

Question 18

PLCs are designed to be programmed with_________ .

Accepted Answer

A)  ladder diagrams 
B)  BASIC 
C)  higher-order languages 
D)  relays 
A)  ladder diagrams 
B)  BASIC 
C)  higher-order languages 
D)  relays

Question 19

The _________is the "brains" of the PLC.

Accepted Answer

A)  power supply 
B)  CPU 
C)  I/O rack 
D)  program loader 
A)  power supply 
B)  CPU 
C)  I/O rack 
D)  program loader

Question 20

Explain the mechanism by which the differential amplifier works.

Accepted Answer

An electronic device that is often used

Exam 17: Programmable Logic Controllers

The PLC recognizes only _________.

A(n) _________is connected across the ac input to help eliminate any voltage spikes that may occur.

What are the advantages and disadvantages of controlling output with small relays?

The current rating of most outputs can range from 0.5 to about _________amperes, depending on the make of the controller and the type of output being used.

Electrical noise is such a problem in some installations that several manufacturers are using_________ instead of wires for connection to the I/O rack.

PLCs were first used by the_________ industry in the late 1960s.

The most popular way to isolate the CPU from the external circuit is through_________ .

The PLC is a special type of _________designed to perform a special function.

The_________ is used to program the CPU.

What are some potential problems you might face when grounding equipment?

In the relay method of isolation, the CPU is isolated through the use of a(n) _________.

What are timers and counters?

Describe the power supply of the PLC.

An electronic device that is often used to help overcome the problem of induced noise is the_________ .

Highlighting a contact means that there is a_________ through that contact.

The_________ is used to connect the CPU to the load.

The actual logic of the control circuit is performed by_________ .

PLCs are designed to be programmed with_________ .

The _________is the "brains" of the PLC.

Explain the mechanism by which the differential amplifier works.

Plans and Sitework

The Unit Substation

Feeder Bus System

Panelboards

Trolley Busways

Using Wire Tables and Determining Conductor Sizes

Signaling Systems

Basic Motor Controls

Motors and Controllers

Motor Installation

Power Factor

Ventilating, Air Conditioning, and Other Facilities

System Protection

Lightning Protection

Luminaires

Site Lighting

Developing a Program for a Plc

Fiber Optics

Hazardous Locations

Harmonics

Filters