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Electrical > Automation - weeks 1/2 > Flashcards

Automation - weeks 1/2 Flashcards

1
Q

programmable logic controllers (PLCs) were first used by??

A
  • automotive industry in late 1960s
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2
Q

each time the design of automobile was changed, what happened w control system operating machinery

A
  • it was changed as well
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3
Q

define: PLC

A
  • special type of computer designed to perform a special function
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4
Q

PLCs are designed to be programmed w what kinds of diagrams (2)?

A
  • schematic
  • ladder
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5
Q

PLCs and PCs employ what type of computer & memory chips?

A
  • employ same type of computer and memory chips to perform intended tasks
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6
Q

PLCs must operate in industrial enviro and be able to: (4)

A
  • withstand extremes of temp
  • ignore voltage spikes and drops on power line
  • survive in atmosphere containing corrosive vapors, oil, and dirt
  • withstand shock and vibration
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7
Q

what are the basic components of PLCs (9)

A
  • power supply
  • central processing unit (CPU) –> PLC “brains”
  • programming terminal
  • I/O rack
  • input module
  • output module
  • internal relays
  • timers and counters
  • off-delay circuit
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8
Q

PLC basic components:
what does the power supply do (3)

A
  • lowers incoming AC voltage to desired level
  • rectifies it to direct current
  • filters and regulates
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9
Q

PLC basic components:
with power supply, internal logic operates on…

A

5 to 24 volts DC

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10
Q

PLC basic components:
with power supply, internal logic must be free of…

A
  • free of voltage spikes and electrical noise
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11
Q

PLC basic components:
with power supply, internal logic must be regulated to…

A
  • within 5% of required voltage value
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12
Q

PLC basic components:
what is a CPU

A
  • contains microprocessor chip & related integrated circuits performing all logic functioning
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13
Q

PLC basic components:
CPUs have a…

A
  • key on front panel (or software switch)
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14
Q

PLC basic components:
describe the purpose of the key on CPUs

A
  • must be turned on before programming
  • prevents program from being changed or deleted
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15
Q

PLC basic components:
with CPUs, plug connections provide….

A
  • connection for programming terminal and I/O racks
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16
Q

PLC basic components:
the programming terminal programs…

A
  • CPU
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17
Q

PLC basic components:
the type of programming terminal depends on… (2)

A
  • manufacturer
  • consumer
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18
Q

PLC basic components:
describe the purpose of small handheld devices (liquid crystal display or light-emitting diodes) on programming terminals

A
  • show program display one line at a time or use Boolean language
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19
Q

PLC basic components:
describe the purpose of display & keyboard on programming terminals

A
  • displays several lines of program and used to observe operation of circuit as it is operating
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20
Q

PLC basic components:
describe the purpose of notebooks (laptop) on programming terminals

A
  • permits computer to be connected to PLC input
  • software program generally available from PLC manufacturer
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21
Q

PLC basic components:
the programming terminal is also used to…

A
  • troubleshoot circuit –> when terminal is connected to CPU, circuit can be examined while in operation
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22
Q

PLC basic components:
what is the purpose of the I/O rack

A
  • connects CPU to outside world
  • contains input modules and output modules
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23
Q

PLC basic components:
what is the purpose of input modules in I/O racks

A
  • carry info from control sensor devices to CPU
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24
Q

PLC basic components:
what is the purpose of output modules in I/O racks

A
  • carry instructions from CPI to output devices in field
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25
Q

PLC basic components:
on I/O racks, modules contains…

A
  • contain more than one input or output
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26
Q

PLC basic components:
what is the I/O capacity

A
  • as few as 16 to several hundred
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27
Q

PLC basic components:
what is the function of internal relays

A
  • performs actual logic
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28
Q

PLC basic components:
internal relays exists only in…

A
  • logic of computer
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29
Q

PLC basic components:
describe programming of internal relays (2)

A
  • any number of contacts that can be programmed normally open or normally closed
  • programmed by assigning a certain number
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30
Q

PLC basic components:
describe programming of timers & counters (4)

A
  • internal relays
  • programmed into logic by number
  • inserted into program
  • generally programmed in 0.1 sec internals or decimal key
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31
Q

PLC basic components:
input module - CPU of PLC

A
  • sensitive to voltage spikes and electrical noise
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32
Q

PLC basic components:
with input modules, the input I/O uses…

A
  • opto-isolation to electrically separate incoming signal from CPU
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33
Q

PLC basic components:
describe the metal-oxide-varistor (MOV) in input modules

A
  • connected across AC input helps eliminate any voltage spikes
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34
Q

PLC basic components:
with input modules, the bridge rectifier changes…

A
  • AC voltage into DC
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35
Q

PLC basic components:
with the input module, the resistor limits current to…

A
  • LED
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36
Q

PLC basic components:
with light modules, light is detected by _______, which signals _______

A
  • detected by a phototransistor, which signals CPU that voltage present at input terminal
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37
Q

PLC basic components:
with input modules, module has ______ input

A
  • more than 1 input
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38
Q

PLC basic components:
with input module, bridge rectifiers are connected together on one side to form a ________. On the other side, rectifiers are labeled _____

A
  • common terminal
  • labelled 1,2,3, and 4
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39
Q

PLC basic components:
the output module connects…

A
  • CPU to load
40
Q

PLC basic components:
the output module provides …

A
  • line isolation between CPU and external circuit
    –> optical isolation
41
Q

PLC basic components:
output modules contains ______ output

A
  • more than one output
42
Q

PLC basic components:
with output modules, one terminal of each output is connected together to form…

A
  • a common terminal
43
Q

PLC basic components:
off-delay circuit –> PLC permits…

A
  • only on-delay timer programming
44
Q

PLC basic components:
off-delay circuit –> simple circuit permits…

A
  • on-delay timer to perform off-delay timer function
45
Q

PLC basic components:
with off-delay circuits, when timer coil is energized …

A
  • timed contacts change position immediately
46
Q

PLC basic components:
with off-delay circuit, when timer coil is de-energized…

A
  • contacts remain in energized state before returning to normal
47
Q

PLC basic components:
with off-delay circuit, memory capacity determines…

A
  • number of internal relays and timers
48
Q

two wire protection provides low voltage…

49
Q

three wire protection provides low voltage….

A
  • protection
50
Q

a control circuit that prevents a piece of equipment from re-starting after a power interruption is called _________

A
  • low voltage protection
51
Q

a device that converts one form of energy to another is called….

A
  • transducer
52
Q

the contacts of a single pole toggle switch can be described as….

A
  • single pole single throw
53
Q

the contacts of a relay, providing there is a common terminal between the N.O and N.C contacts, would be described as….

A
  • single pole double throw
54
Q

what are the 2 parts of a solenoid

A
  • coil
  • plunger
55
Q

items that do not physically exist, but are both part of a PLC program only are

A
  • internal contacts and internal coils
56
Q

which rule regarding PLC programming is false

A
  • each line of logic must end w a contact
57
Q

in a PLC program, inputs, such as push buttons, float switches, etc. are represented by

A
  • contact symbols (N/O, N/C)
58
Q

if more than one output circuit (internal circuitry) is contained in a module, the module…

A
  • should have a common terminal
59
Q

a numbering system that contains only 8 digits, 0 through 7, is called…

60
Q

if a PLC internal timer has a time internal of 0.1 seconds and is to be used for a delay of 3 minutes, what number is used to set this timer

61
Q

when a PLC is used to start a 30 (weird O) motor, the output module is used to…

A
  • energize the motor starter coil
62
Q

a PLC recognizes internal relay and timer contacts by

A
  • the contact’s address
63
Q

a relay schematic is converted into a ______ to ______

A
  • converted into a diagram to program a programmable controller
64
Q

when developing a program, before developing for input, assign devices connections to…

A
  • input and output terminal
65
Q

a motor starter contains an overload relay with…

A
  • 2 contacts –> 1 open and 1 closed
66
Q

what are 4 rules for converting the program

A
  • each line of logic must end w a coil
  • coils cannot be connected in parallel
  • the program will be scanned in order it is entered
  • generally, coils cannot be assigned same number
67
Q

programming in boolean may be necessary at times to…

A
  • use a small programming device (handheld or that attaches directly to the CPU)
68
Q

with a SERIES ONE programmable controller, all coil and I/O references must be entered in…

69
Q

which industry first used programmable logic controllers

A
  • automotive industry
70
Q

a programmable logic controller is a special kind of

A
  • industrial computer
71
Q

most PLCs are designed to be programmed in

A
  • ladder logic
72
Q

list the 4 major components of a PLC

A
  • power supply
  • CPU
  • programming terminal
  • I/O rack
73
Q

a PLC power supply must be able to regulate voltage within

A

5% of the required value

74
Q

in a PLC, all logic functions are performed by the

75
Q

manufacturers use one of two devices to prevent a program from being accidentally deleted. what are the 2 devices?

A
  • key
  • software switch
76
Q

another name for the programming terminal is the _____ terminal

77
Q

the PLC’s terminal is used to (3)

A
  • program the controller
  • troubleshoot the PLC
  • monitor PCU operations
78
Q

are NEMA symbols such as pushbuttons, limit switched, or selector switches used in PLC ladder diagrams

79
Q

how are contacts of a PLC ladder diagram identified

80
Q

with a PLC, if a laptop or notebook computer were connected to the PLC, the laptop of notebook computer would be referred to as the….

81
Q

in a ladder diagram, each line ends w a ….

82
Q

how are coils of a PLC ladder diagram symbolized

A

w brackets

83
Q

if a PLC had 8 output modules w 12 connections for loads per module, how much loads could the PLC control

A

96 output devices

84
Q

what part of the PLC is referred to as the “brains” of the PLC

85
Q

what type of isolation is generally used to electrically separate outside voltages from the internal circuitry of the PLC

86
Q

what is connected across the AC input to help eliminate any voltage spikes that may occur on the line

A
  • metal oxide varistor (MOV)
87
Q

what parts of the PLC connects the CPU to the real world input/output devices

A
  • output/input module
88
Q

if an output module controls a DC voltage, what solid-state device is used to connect the load to the line

A
  • power phototransistor
89
Q

if an output module controls an AC voltage, what solid-state device is used to connect the load to the line

A
  • triac or phototriac
90
Q

in PLC’s, timers and counters are

A
  • computer generated and internal relays
91
Q

pushbuttons, limit switches and float switches would be considered

A
  • input devices
92
Q

when a PLC utilizes opto-isolation, what device is used to either signal the CPU that a voltage is present at an input terminal, or the CPU to signal a solid state device to connect the load to the line

A
  • light emitting diode (LED)
93
Q

the power to operate loads such as starter coils, indicating lights, or solenoid valves must be provided by

A
  • an external source
94
Q

the amt of current output modules can handle is generally….

A

0.5-3.0 ampres

95
Q

when may an interposing relay be used

A
  • when the amperage of the load exceeds the rating of the output module
96
Q

with a PLC, an internal relay is a

A
  • computer generated device
97
Q

has an internal timer w a time internal of 0.1 seconds. if the timer were to provide a delay of 100 seconds, what number would be assigned to the timer

Electrical (13 decks)

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