Automation - weeks 1/2 Flashcards
1
Q
programmable logic controllers (PLCs) were first used by??
A
- automotive industry in late 1960s
2
Q
each time the design of automobile was changed, what happened w control system operating machinery
A
- it was changed as well
3
Q
define: PLC
A
- special type of computer designed to perform a special function
4
Q
PLCs are designed to be programmed w what kinds of diagrams (2)?
A
- schematic
- ladder
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
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
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
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
9
Q
PLC basic components:
with power supply, internal logic operates on…
A
5 to 24 volts DC
10
Q
PLC basic components:
with power supply, internal logic must be free of…
A
- free of voltage spikes and electrical noise
11
Q
PLC basic components:
with power supply, internal logic must be regulated to…
A
- within 5% of required voltage value
12
Q
PLC basic components:
what is a CPU
A
- contains microprocessor chip & related integrated circuits performing all logic functioning
13
Q
PLC basic components:
CPUs have a…
A
- key on front panel (or software switch)
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
15
Q
PLC basic components:
with CPUs, plug connections provide….
A
- connection for programming terminal and I/O racks
16
Q
PLC basic components:
the programming terminal programs…
A
- CPU
17
Q
PLC basic components:
the type of programming terminal depends on… (2)
A
- manufacturer
- consumer
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
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
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
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
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
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
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
25
PLC basic components:
on I/O racks, modules contains...
- contain more than one input or output
26
PLC basic components:
what is the I/O capacity
- as few as 16 to several hundred
27
PLC basic components:
what is the function of internal relays
- performs actual logic
28
PLC basic components:
internal relays exists only in...
- logic of computer
29
PLC basic components:
describe programming of internal relays (2)
- any number of contacts that can be programmed normally open or normally closed
- programmed by assigning a certain number
30
PLC basic components:
describe programming of timers & counters (4)
- internal relays
- programmed into logic by number
- inserted into program
- generally programmed in 0.1 sec internals or decimal key
31
PLC basic components:
input module - CPU of PLC
- sensitive to voltage spikes and electrical noise
32
PLC basic components:
with input modules, the input I/O uses...
- opto-isolation to electrically separate incoming signal from CPU
33
PLC basic components:
describe the metal-oxide-varistor (MOV) in input modules
- connected across AC input helps eliminate any voltage spikes
34
PLC basic components:
with input modules, the bridge rectifier changes...
- AC voltage into DC
35
PLC basic components:
with the input module, the resistor limits current to...
- LED
36
PLC basic components:
with light modules, light is detected by _______, which signals _______
- detected by a phototransistor, which signals CPU that voltage present at input terminal
37
PLC basic components:
with input modules, module has ______ input
- more than 1 input
38
PLC basic components:
with input module, bridge rectifiers are connected together on one side to form a ________. On the other side, rectifiers are labeled _____
- common terminal
- labelled 1,2,3, and 4
39
PLC basic components:
the output module connects...
- CPU to load
40
PLC basic components:
the output module provides ...
- line isolation between CPU and external circuit
--> optical isolation
41
PLC basic components:
output modules contains ______ output
- more than one output
42
PLC basic components:
with output modules, one terminal of each output is connected together to form...
- a common terminal
43
PLC basic components:
off-delay circuit --> PLC permits...
- only on-delay timer programming
44
PLC basic components:
off-delay circuit --> simple circuit permits...
- on-delay timer to perform off-delay timer function
45
PLC basic components:
with off-delay circuits, when timer coil is energized ...
- timed contacts change position immediately
46
PLC basic components:
with off-delay circuit, when timer coil is de-energized...
- contacts remain in energized state before returning to normal
47
PLC basic components:
with off-delay circuit, memory capacity determines...
- number of internal relays and timers
48
two wire protection provides low voltage...
- release
49
three wire protection provides low voltage....
- protection
50
a control circuit that prevents a piece of equipment from re-starting after a power interruption is called _________
- low voltage protection
51
a device that converts one form of energy to another is called....
- transducer
52
the contacts of a single pole toggle switch can be described as....
- single pole single throw
53
the contacts of a relay, providing there is a common terminal between the N.O and N.C contacts, would be described as....
- single pole double throw
54
what are the 2 parts of a solenoid
- coil
- plunger
55
items that do not physically exist, but are both part of a PLC program only are
- internal contacts and internal coils
56
which rule regarding PLC programming is false
- each line of logic must end w a contact
57
in a PLC program, inputs, such as push buttons, float switches, etc. are represented by
- contact symbols (N/O, N/C)
58
if more than one output circuit (internal circuitry) is contained in a module, the module...
- should have a common terminal
59
a numbering system that contains only 8 digits, 0 through 7, is called...
- octal
60
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
1800
61
when a PLC is used to start a 30 (weird O) motor, the output module is used to...
- energize the motor starter coil
62
a PLC recognizes internal relay and timer contacts by
- the contact's address
63
a relay schematic is converted into a ______ to ______
- converted into a diagram to program a programmable controller
64
when developing a program, before developing for input, assign devices connections to...
- input and output terminal
65
a motor starter contains an overload relay with...
- 2 contacts --> 1 open and 1 closed
66
what are 4 rules for converting the program
- 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
programming in boolean may be necessary at times to...
- use a small programming device (handheld or that attaches directly to the CPU)
68
with a SERIES ONE programmable controller, all coil and I/O references must be entered in...
OCTAL
69
which industry first used programmable logic controllers
- automotive industry
70
a programmable logic controller is a special kind of
- industrial computer
71
most PLCs are designed to be programmed in
- ladder logic
72
list the 4 major components of a PLC
- power supply
- CPU
- programming terminal
- I/O rack
73
a PLC power supply must be able to regulate voltage within
5% of the required value
74
in a PLC, all logic functions are performed by the
CPU
75
manufacturers use one of two devices to prevent a program from being accidentally deleted. what are the 2 devices?
- key
- software switch
76
another name for the programming terminal is the _____ terminal
loading
77
the PLC's terminal is used to (3)
- program the controller
- troubleshoot the PLC
- monitor PCU operations
78
are NEMA symbols such as pushbuttons, limit switched, or selector switches used in PLC ladder diagrams
- no
79
how are contacts of a PLC ladder diagram identified
- a number
80
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....
- terminal
81
in a ladder diagram, each line ends w a ....
- coil
82
how are coils of a PLC ladder diagram symbolized
w brackets
83
if a PLC had 8 output modules w 12 connections for loads per module, how much loads could the PLC control
96 output devices
84
what part of the PLC is referred to as the "brains" of the PLC
- CPU
85
what type of isolation is generally used to electrically separate outside voltages from the internal circuitry of the PLC
- optical
86
what is connected across the AC input to help eliminate any voltage spikes that may occur on the line
- metal oxide varistor (MOV)
87
what parts of the PLC connects the CPU to the real world input/output devices
- output/input module
88
if an output module controls a DC voltage, what solid-state device is used to connect the load to the line
- power phototransistor
89
if an output module controls an AC voltage, what solid-state device is used to connect the load to the line
- triac or phototriac
90
in PLC's, timers and counters are
- computer generated and internal relays
91
pushbuttons, limit switches and float switches would be considered
- input devices
92
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
- light emitting diode (LED)
93
the power to operate loads such as starter coils, indicating lights, or solenoid valves must be provided by
- an external source
94
the amt of current output modules can handle is generally....
0.5-3.0 ampres
95
when may an interposing relay be used
- when the amperage of the load exceeds the rating of the output module
96
with a PLC, an internal relay is a
- computer generated device
97
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
1000
