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
