Rockwell Automation 1772-L8_LW_LWP_LX_LXP,D17726.5.8 User Manual User Manual

Page 213

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EAF

Process Control Instructions

Chapter 16

16-2

PID Features

The PID EAF instruction provides the following features:

Selectable dependent or independent gain PID equations
Manual to automatic mode with bumpless transfer
Derivative term calculates from PV or error
Process variable and setpoint scaled to engineering units
Output

alarms

Output limiting with anti-reset windup
Zero crossing dead band
Feedforward or output biasing
Direct or reverse control action

Concepts

PID Closed Loop Control (Figure 16.2) holds a physical quantity such as
pressure, temperature, or flow rate at a desired value (set point).

Figure 16.2

Loop Control With A PID Controller

PID

Equation

FFWD

or

Bias

Σ

Set Point

Error

Flow

Rate

Process

Variable

Level

Detector

Control

Output

Control

Valve

10372-I

Σ

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