PLC & SCADA Module-1 Quiz

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