WorksheetsPLC & SCADA Module-1 Quiz
Total questions: 25
Worksheet time: 13mins
Which of the following is not an advantage of a PLC compared to relay-based systems?
Smaller size
Higher reliability
Slower response time
Easy modification
What is the primary function of a PLC's input module?
To convert input signals to a readable format
To execute control logic
To store the program
To provide power to the PLC
The first generation of PLCs were mainly designed to replace:
SCADA systems
Pneumatic control systems
Hard-wired relay logic
CNC machines
Which type of PLC is most suitable for stand-alone small applications?
Modular PLC
Rack-mounted PLC
Unitary PLC
Distributed PLC
The CPU of a PLC primarily performs:
Power conditioning
Execution of control program
Signal amplification
Input wiring
In a PLC, the memory section stores:
Ladder programs only
I/O wiring diagrams
Program and data
Only executive software
The scan cycle of a PLC includes:
Input scan → Program execution → Output update
Program execution → Output update → Input scan
Output update → Input scan → Program execution
Input scan → Output update → Program execution
Which language is most widely used in PLC programming?
Ladder Logic
Instruction List
Structured Text
Sequential Function Chart
In ladder logic, the normally open contact is represented by:
---| |---
---(L)---
---( )---
---|/|---
Which logic gate is equivalent to two contacts in series in a ladder diagram?
OR gate
AND gate
NOT gate
NAND gate
A rung with parallel contacts in ladder logic represents:
AND logic
OR logic
NOT logic
XOR logic
In PLC symbols, the output coil is generally represented as:
( )
[ ]
{ }
/ /
Which timer retains its accumulated value even after the rung goes false?
Non-retentive timer
Retentive timer
Pulse timer
On-delay timer
The instruction CTU in PLC stands for:
Counter Type Up
Count Up
Control Timer Unit
Counter Time Utilization
Which counter instruction decreases the accumulated value?
CTU
CTD
TON
RTO
In Allen Bardley PLC, the time base for timers is:
1 ms
1 s
10 ms
100 ms only
Which of the following parameters defines a counter?
Preset value
Accumulated value
Count direction
All of the above
The instruction JMP in a PLC is used for:
Jumping to a specific I/O
Jumping to a labeled rung
Jumping out of scan cycle
Jumping to an interrupt routine
The LBL instruction is associated with:
Loop control
Defining a jump target
Counter reset
Subroutine initialization
Which instruction is used to call a subroutine in PLC?
JSR
RET
JMP
LBL
The instruction RET in PLC programming indicates:
Return to last rung
Return from subroutine
Retentive timer reset
Restart execution
The SBR instruction defines:
Start of a subroutine
Subroutine return
Sequential block reset
Sub-block reference
Which of the following is a common communication protocol used in PLCs?
HTTP
SMTP
FTP
Ethernet/IP
What does the instruction DIV do in a PLC?
Divides two values and return dividend
Displays output
Divides two values and return Quotient
Divides two values and return Remainder
In PLC programming, what is the primary difference between INT and DINT data types?
INT can only store positive values, while DINT can store negative values
INT is 16 bits, while DINT is 32 bits
INT is 8 bits, while DINT is 16 bits
There is no difference; they are interchangeable
