PLC Programming

3.

PLC Hardware Architecture and Components

3.1.

Central Processing Unit Architecture

3.1.1.

Processor Types and Specifications

3.1.2.

Processing Speed Considerations

3.1.3.

Memory Architecture

3.1.3.1.

Random Access Memory

3.1.3.2.

Read-Only Memory

3.1.3.3.

3.1.3.4.

Battery-Backed Memory

3.1.4.

Operating Modes

3.1.4.1.

Run Mode Operation

3.1.4.2.

Program Mode Operation

3.1.4.3.

Remote Mode Operation

3.1.4.4.

Test Mode Operation

3.1.5.

Built-in Communication Ports

3.1.5.1.

Serial Communication Ports

3.1.5.2.

Ethernet Communication Ports

3.1.5.3.

USB Programming Ports

3.1.5.4.

Specialty Communication Ports

3.2.

Power Supply Systems

3.2.1.

Input Voltage Requirements

3.2.2.

Output Voltage Specifications

3.2.3.

Power Consumption Calculations

3.2.4.

Backup Power Systems

3.2.5.

Redundant Power Supplies

3.2.6.

Power Quality Considerations

3.3.

Input/Output System Architecture

3.3.1.

I/O System Organization

3.3.2.

Rack and Chassis Systems

3.3.2.1.

Modular I/O Systems

3.3.2.2.

Fixed I/O Systems

3.3.2.3.

Expansion Capabilities

3.3.3.

Local I/O Configuration

3.3.4.

Remote I/O Systems

3.3.4.1.

Communication Methods

3.3.4.2.

Distance Limitations

3.3.4.3.

Advantages and Applications

3.4.

Digital Input Modules

3.4.1.

DC Input Modules

3.4.1.1.

Voltage Levels and Ranges

3.4.1.2.

Current Requirements

3.4.1.3.

3.4.2.

AC Input Modules

3.4.2.1.

Voltage Specifications

3.4.2.2.

Frequency Considerations

3.4.3.

Input Signal Conditioning

3.4.4.

Electrical Isolation

3.4.5.

Input Filtering

3.5.

Digital Output Modules

3.5.1.

Relay Output Modules

3.5.1.1.

Contact Ratings

3.5.1.2.

Switching Capabilities

3.5.1.3.

Mechanical Life

3.5.2.

Transistor Output Modules

3.5.2.1.

Switching Speed

3.5.2.2.

Current Limitations

3.5.2.3.

Protection Features

3.5.3.

Triac Output Modules

3.5.3.1.

AC Load Control

3.5.3.2.

Zero-Crossing Switching

3.5.4.

Output Protection Circuits

3.6.

Analog Input Modules

3.6.1.

Voltage Input Modules

3.6.1.1.

3.6.1.2.

Resolution Specifications

3.6.1.3.

Accuracy Specifications

3.6.2.

Current Input Modules

3.6.2.1.

Standard Current Loops

3.6.2.2.

Two-Wire and Four-Wire Connections

3.6.3.

Signal Conditioning Requirements

3.6.4.

Analog-to-Digital Conversion

3.6.5.

Calibration Procedures

3.7.

Analog Output Modules

3.7.1.

Voltage Output Modules

3.7.2.

Current Output Modules

3.7.3.

Digital-to-Analog Conversion

3.7.4.

Output Resolution and Accuracy

3.7.5.

Load Considerations

3.8.

Specialty I/O Modules

3.8.1.

High-Speed Counter Modules

3.8.1.1.

Counter Types and Modes

3.8.1.2.

Input Frequency Limitations

3.8.1.3.

Configuration Options

3.8.2.

Temperature Input Modules

3.8.2.1.

RTD Input Modules

3.8.2.2.

Thermocouple Input Modules

3.8.2.3.

Cold Junction Compensation

3.8.3.

Motion Control Modules

3.8.3.1.

Stepper Motor Control

3.8.3.2.

Servo Motor Control

3.8.3.3.

Position Feedback Systems

3.8.4.

Communication Modules

3.8.4.1.

Protocol Support Options

3.8.4.2.

Network Interface Capabilities

3.8.5.

Safety I/O Modules

3.8.6.

Weighing and Load Cell Modules

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2. Fundamentals of Programmable Logic Controllers

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4. Field Devices and Instrumentation