Programmable Logic Controllers

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Programmable Logic Controllers

• Day 4 Analog Control

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Agenda
Control Theory
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Control Types

• Analog
• Open Loop (w/o feedback)
• Closed Loop (w/feedback)
• PID
• Digital
• Open Loop (w/o feedback)
• Closed Loop (w/feedback)
• PID
• Sequential
• Open Loop (w/o feedback)
• Closed Loop (w/feedback)
• DSP
• Other
• Artificial Neural Networks
• Fuzzy Logic

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Control Platforms

• Mechanical
• Analog Electrical
• Microprocessor
• Pneumatic/Hydraulic
• PLC

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Basic Elements of Control System

• Comparison Element
• Control Element
• Correction Element
• Process Element
• Measurement Element

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Comparison Element

• Error Signal Reference Value Measured Value
• Positive vs. Negative Feedback

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Control Element

• Decision Element
• PID/Sequential/Analog/DSP

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Correction Element

• Actuator
• Changes the Process

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Process Element

• What is being controlled
• Temperature/Velocity/Angle/Displacement

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Measurement Element

• Feedback related to Process
• Transducer

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Control Examples

• Thermostat
• Motor Speed/Position
• Water Tower
• Washing Machine