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WorksheetsPLC ONE
Total questions: 79
Worksheet time: 42mins
Name
Class
Date
1.
PLC has replaced__________
a)
Transistor
b)
Computer
c)
Relay Logic
d)
Solenoid
2.
Disadvantage of PLC is _________
a)
Security
b)
Documentation
c)
Fixed program application
d)
Pilot running
3.
PLC stands for_______
a)
Programmable Ladder Controller
b)
Program Low Controller
c)
Programmable Logic Controller
d)
Programmable Logic Converter
4.
If the I/O Count of PLC is between 32 to 128 then it is called as ___________.
a)
Micro PLCs
b)
Medium PLCs
c)
Small PLCs
d)
Large PLCs
5.
Output modules are available in various switching and _______configurations.
a)
AC
b)
DC
c)
Relay
d)
Transistor
6.
The devices connected to PLC for sending status information are called _______field devices.
a)
Programmer and monitoring
b)
Memory
c)
Output
d)
Input
7.
Hand held terminals is an example for___________.
a)
CPU
b)
Input Module
c)
output Module
d)
Programmer and monitoring
8.
In PLC the user program is stored in ________ memory.
a)
ROM
b)
PROM
c)
EPROM
d)
EEPROM
9.
Input modules provide an interface between ______________and_____________.
a)
Input connections and the CPU
b)
Field equipment and the CPU
c)
Output modules and field devices
d)
The CPU and output modules
10.
PLC I/O systems provides an interface between __________ and ___________.
a)
Input devices and the CPU
b)
Field equipment and the CPU
c)
Output modules and field devices
d)
Input modules and output modules
11.
Electrical isolation is provided so that there is no physical electrical connection between the CPU and output field devices. This isolation is usually accomplished by____________
a)
Power supply
b)
Rectifier
c)
Opto coupler
d)
Holding Register
12.
1K of memory is equal to ________
a)
1000 bits
b)
1000 words
c)
1024 bits
d)
1024 words
13.
Power signal that the output module switches to control field devices must be provided by__________
a)
The CPU
b)
The user
c)
The master control relay
d)
Relay
14.
A _____ is usually mounted on one end of each rack, backplane, or chassis.
a)
CPU
b)
single power supply
c)
memory card
d)
I/O Card
15.
The programming device must be connected ____________ to the controller
a)
At all times
b)
When entering a programme
c)
When monitoring a programme
d)
When entering or monitoring a programme
16.
The basic difference between plc and relay control system is ___________
a)
Different input and output voltage levels are used
b)
Different types of output devices are used
c)
Different types of input devices are used
d)
One uses relay control logic & other uses programmed instructions
17.
The abbreviations NO and NC represents the electrical state of switch contacts when_______________.
a)
Power is applied
b)
Power is not applied
c)
The switch is actuated
d)
The switch is not actuated
18.
NC push button connected in hardware & NC contact in software then the coil connected to the NC contact will be ___________
a)
ON
b)
OFF
c)
Short
d)
Toggle
19.
A limit switch is usually actuated by_________.
a)
Hand
b)
Pressure
c)
Contact with an object
d)
An electromagnet
20.
A thermocouple ,when heated _______
a)
Produces a small dc voltage
b)
Increases its resistance value
c)
Produces a small AC voltage
d)
Decreases its resistance value
21.
A________converts electrical pulses applied to it into discrete rotor movement
a)
Tachometer
b)
Solenoid
c)
Stepper motor
d)
Electronic magnetic flow meter
22.
Digital I/O modules operate on___________
a)
24V AC supply
b)
24V DC supply
c)
5V AC supply
d)
12V DC supply
23.
PNP type proximity sensor is compatible with __________ input module.
a)
Sourcing
b)
Sinking
c)
AC
d)
DC
24.
NPN type proximity sensor is compatible with __________ input module
a)
sourcing
b)
sinking
c)
AC
d)
DC
25.
Discrete input modules accept signals from field devices that are________
a)
Analog type
b)
Digital Type
c)
Two-state Type
d)
Digital or Two state type
26.
A discrete input signal is considered valid if the signal is________
a)
Is a two-state signal
b)
Is successfully change from AC to DC through the bridge rectifier
c)
For an AC signal, if it is between 80 & 132 VAC
d)
If it is continous
27.
Thumbwheels switches provide input to the PLC in _______ format
a)
BCD
b)
Binary
c)
DECIMAL
d)
Hexadecimal
28.
Discrete output interface modules send signals to field devices that are__________
a)
Digital devices
b)
Analog devices
c)
Two-state devices
d)
Digital or Two state Device
29.
Discrete output modules act as a _________ to control output field devices
a)
Relay
b)
Switch
c)
Contactor
d)
solenoid
30.
Typical discrete output devices include_______
a)
Servo Motor
b)
Inductive proximity switches
c)
Solenoids
d)
LVDT
31.
Changing signals like temperature control or the 4 to 20-milliamp-speed reference for a variable-frequency drive are called ______ signals
a)
analog input
b)
digital input
c)
analog output
d)
digital output
32.
Suppose you need to select a module to interface AC or DC, two-state, ON/OFF, or OPEN/CLOSED incoming signals.which will you choose
a)
analog input module
b)
analog output module
c)
discrete input module
d)
combination of Analog and discrete input module
33.
Suppose you need to select a module to inter face out going AC or DC,two state, ON/OFF, or OPEN/CLOSED outgoing signals.Which will you choose
a)
discrete output module
b)
analog output module
c)
discrete input module
d)
Analog input module
34.
Suppose you need to select a module to interface a continuously changing incoming voltage or current signal.which will you choose
a)
analog input module
b)
analog output module
c)
discrete input module
d)
combination of Analog and discrete input module
35.
A discrete input module which can be interfaced is ___________
a)
push buttons
b)
Horn
c)
contactor
d)
Pilot lamp
36.
Volatile memory is__________
a)
RAM
b)
ROM
c)
PROM
d)
EEPROM
37.
Nonvolatile memory is________
a)
RAM
b)
ROM
c)
PROM
d)
EEPROM
38.
The processor in any PLC is designed to perform specific duties in a specific sequence and then continuously repeat the sequence.The operating cycle is called __________
a)
Access time
b)
Operating system
c)
Scan Cycle
d)
scan time
39.
The scan consists of a series of sequential operations which include, Reading________, program execution, data output
a)
connection
b)
Input
c)
Output
d)
Tie point
40.
If the input devices change its state while the processor is in program scan or output scan of the scan cycle then the plc will _____________
a)
Immediately react to them
b)
React during the next scan cycle
c)
Response very slow
d)
Does not react to them
41.
If two NC contacts are connected in series that satisfies _______Gate logic
a)
AND
b)
NAND
c)
OR
d)
NOR
42.
NC contact can be used to satisfy ________gate condition.
a)
NOT
b)
OR
c)
AND
d)
NOR
43.
If two NO contacts are connected in series that satisfies _______Gate logic.
a)
OR
b)
NAND
c)
NOR
d)
AND
44.
If two NC contacts are connected in parallel that satisfies _______Gate logic.
a)
AND
b)
NAND
c)
OR
d)
NOR
45.
The logical OR function is similar to connecting two NO contacts in _____________
a)
parallel
b)
series
c)
Direct reversal
d)
Indirect reversal
46.
Status of input devices are stored in ________ Register.
a)
Output single
b)
Input single
c)
Output group
d)
Input group
47.
Each instruction on a ladder diagram has a reference number associated with it which is_________
a)
Its instruction comment
b)
Its position identifier on the ladder rung
c)
a number referencing the instructions associated input status table bit addrress
d)
the instructions input address
48.
Holding register is also known as_______.
a)
Input register
b)
Output Register
c)
Working Register
d)
Group Register
49.
Address O1: 02/00, in which ‘:’ is known as__________.
a)
Bit delimiter
b)
File delimiter
c)
Rack No.
d)
File No.
50.
Address I1: 02/00, in which ‘I’ is known as__________.
a)
Terminal No.
b)
File Type
c)
Rack No.
d)
File No.
51.
Address O1: 02/00, in which ‘/’ is known as__________.
a)
Bit delimiter
b)
File delimiter
c)
Rack No.
d)
File No.
52.
The main difference between a TON and a TOF timer is ___________
a)
TON maintains accumulated time on loss of power to rung logic while TOFF cannot.
b)
TOFF maintains accumulated time on loss of power to rung logic while TON cannot.
c)
TOFF timer begins timing when logic continuity, to rung is lost and TON begins timing when logic continuity to rung is maintained
d)
TON timer begins timing when logic continuity to the timing rung is lost and TOFF viceversa
53.
The______ specifies at what rate the timer will increment
a)
preset time
b)
base time
c)
reset time
d)
rise time
54.
A _________timer initiates an action at a specified time after enable input is made low.
a)
ON delay timer
b)
OFF delay Timer
c)
Retentive timer
d)
Pulse repetitive Timer
55.
For Retentive timers ________input is mandatory.
a)
Enable
b)
Marker relay
c)
Reset
d)
Active
56.
A timer that initiates an action at a specified time after enable input is made high is called ________.
a)
ON delay timer
b)
OFF delay Timer
c)
Retentive timer
d)
Pulse repetitive Timer
57.
single input timer is called __________.
a)
Non retentive
b)
Retentive
c)
Pulse timer
d)
Pulse repetitive Timer
58.
The major advantage of retentive timer is __________.
a)
It has only one input
b)
It looses accumulated time
c)
It has only on delay
d)
It retains accumulated time
59.
Pulse Repetitive Timer means__________.
a)
timer which gives one pulse for each scan time
b)
timer which doesn’t have any preset value
c)
ON delay timer
d)
OFF delay timer
60.
A counter that starts from preset value and increments downward to zero is called _______ counter.
a)
Down
b)
UP
c)
UP/DOWN
d)
Non retentive counter
61.
Almost all PLC counters count the_______ of the rungs input logic
a)
Preset count
b)
pulse
c)
DC
d)
AC
62.
As an output, the counter instruction counts each time the_____ changes from a false to a true rung.
a)
count I/P
b)
Reset I/P
c)
Enable I/P
d)
count O/P
63.
A counters input signal can be from an external device, such as a limit switch or sensor, or even from______
a)
Timer
b)
RTD
c)
LVDT
d)
Stepper motor
64.
Each time the counter instruction sees a ________, a up counters accumulated value is incremented by one.
a)
True to False Transition
b)
False to True Transition
c)
continuous
d)
False Transition
65.
when working with counters one important consideration is the ________ or _________, at which an input device is sending the false-to-true signals to the processor.
a)
up, down
b)
voltage, current
c)
speed, frequency
d)
Done,over flow
66.
The numerical range within which a counter can count is ____________.
a)
32767
b)
32768
c)
32676
d)
32678
67.
A _______instruction will Reset the counter to zero.
a)
Enable
b)
Marker relay
c)
Reset
d)
Set
68.
HSC stands for _________
a)
High Sequence Counter
b)
High Standard Counter
c)
High Speed Counter
d)
Higher secondary counter
69.
Operation of High speed counters are________
a)
Independent of scan time
b)
Dependent on scan time.
c)
User dependent
d)
program dependent
70.
Which of the following is not usually associated with a PLC COUNTER
a)
Address
b)
Preset value
c)
Time base
d)
Accumulated value
71.
The PLC counter instruction is similar to the ________
a)
Internal relay instructions
b)
Transitional contact instruction
c)
Timer instructions
d)
Relay coil and contact instructions
72.
The output of a PLC counter is energized when the___________
a)
Count input rung is true
b)
Count input rung is false
c)
Accumulated count is equal to the preset count
d)
Preset count is greater than the accumulated count
73.
Each time a down counter sees a _______, its accumulated value is decremented by one
a)
True to False Transition
b)
False to True Transition
c)
continuous
d)
False Transition
74.
In PLC subtraction function output goes high, if ________.
a)
result is negative
b)
result is positive
c)
result is zero
d)
Result Is more Positive
75.
In PLC Addition function output goes high, if ________.
a)
result is negative
b)
result is positive
c)
register value over flows
d)
Result Is more Negative
76.
In PLC division function Destination 1'st Register contains ________.
a)
Reminder
b)
Quotient
c)
Divisor
d)
Dividend
77.
SQR stands for__________.
a)
Sequencer
b)
Square root
c)
Sine
d)
sign magnitude
78.
In PLC Multiplication function output coil goes ON, ___________
a)
If multiplication is completed
b)
if Destination Register value is negative
c)
if Destination Register value is positive
d)
if Destination Register value is Zero
79.
In PLC Division function output coil goes ON, ___________
a)
if Division is completed
b)
if Destination Register value is negative
c)
if Destination Register value is positive
d)
if Destination Register value is Zero
Reset