Watlow PM PLUS 6 User Manual

Watlow PM PLUS™ 6 • 91 • Chapter 8: Features
Proportional, Integral and Derivative (PID) Control
Use derivative (rate) control to minimize the overshoot in a PI-controlled system. Derivative (rate) adjusts
the output based on the rate of change in the temperature or process value. Too much derivative (rate) will
make the system sluggish. Adjust the derivative with Time Derivative
td (Operations Page, Loop Menu).
Dead Band
In a PID application the dead bands above and below the set point can save an application’s energy and wear
by maintaining process temperature within acceptable ranges.
Proportional action ceases when the process value is within the dead band. Integral action continues to
bring the process temperature to the set point. Using a
positive dead band value keeps the two systems from
fighting each other.
When the dead band value is zero, the heating output activates when the temperature drops below the set
point, and the cooling output switches on when the temperature exceeds the set point.
Time
Temperature
Positive Dead Band
Set Point
Heat Output Active
Cool Output Active
Time
Temperature
Zero Dead Band
Set Point
Heat Output Active
Cool Output Active
When the dead band value is a negative value, both heating and cooling outputs are active when the tem-
perature is near the set point.
Go to Operations — Setup — Control Loop — Deadband to adjust.
Time
Temperature
PID Control
Set Point
Reduced Overshoot
Proportional Band

Watlow PM PLUS 6 Specifications

General

Brand	Watlow
Model	PM PLUS 6
Category	Controller
Language	English