Lesson 2 PLC Systems

What is a Unitary PLC?

• A rack-mounted system

• A large system

• A modular design

• A compact unit

Answer explanation

A Unitary PLC is designed as a compact unit, making it suitable for smaller applications where space is limited. This distinguishes it from larger, rack-mounted or modular systems.

Which component is the brain of the PLC?

• Communication Modules

• Processor (CPU)

• I/O Modules

• Power Supply

Answer explanation

The Processor (CPU) is the brain of the PLC, responsible for executing control instructions and processing data. Other components like communication modules, I/O modules, and power supply support the CPU but do not perform its core functions.

What is a key advantage of Unitary PLCs?

• High cost

• Complexity

• Cost-effectiveness

• Limited expansion

Answer explanation

A key advantage of Unitary PLCs is their cost-effectiveness, making them an economical choice for various applications. This contrasts with high cost, complexity, and limited expansion, which are not advantages.

Which PLC type is best for complex tasks?

• None of the above

• Rack-mounted

• Modular

• Unitary

Answer explanation

Modular PLCs are best for complex tasks due to their flexibility and scalability. They allow for the addition of various modules to handle different functions, making them suitable for intricate automation processes.

What is a limitation of Unitary PLCs?

• Robustness

• Advanced communication

• Limited expansion

• High scalability

Answer explanation

Unitary PLCs have a limitation in terms of limited expansion, meaning they cannot easily accommodate additional I/O modules or features. This restricts their ability to grow with increasing system demands.

What type of PLC is housed in a rack?

• Rack-mounted

• Modular

• Standalone

• Unitary

Answer explanation

A rack-mounted PLC is specifically designed to be installed in a rack, allowing for modularity and easy access to components. This distinguishes it from standalone and unitary types, which are not housed in racks.

Which industry commonly uses Modular PLCs?

• Food and Beverage

• Utilities

• Manufacturing

• Building Automation

Answer explanation

Modular PLCs are widely used in the manufacturing industry due to their flexibility and scalability, allowing for efficient control of complex processes and machinery, making them ideal for production environments.

What is a feature of Rack-mounted PLCs?

• Compact size

• Hot-swappable modules

• Standalone control

• Limited I/O

Answer explanation

Hot-swappable modules are a key feature of rack-mounted PLCs, allowing users to replace or add components without shutting down the system, enhancing flexibility and minimizing downtime.

What is a disadvantage of Modular PLCs?

• High cost

• Compact design

• Simple programming

• Easy installation

Answer explanation

A disadvantage of Modular PLCs is their high cost. While they offer benefits like compact design, simple programming, and easy installation, the initial investment can be significantly higher compared to other types of PLCs.

Which PLC type is ideal for small-scale applications?

• Rack-mounted

• None of the above

• Modular

• Unitary

Answer explanation

Unitary PLCs are compact and designed for small-scale applications, making them ideal for simple control tasks. They integrate all components in one unit, which saves space and simplifies installation.