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Appendix a: pid tuning and control, Introduction, Control modes – Watlow ANASOFT User Manual

Page 67

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Appendix A: PID Tuning and

ANASOFT User’s Guide 57

Appendix A: PID Tuning and

Control

Introduction

This chapter explains PID control and supplies some starting PID values
and tuning instructions, so that you can use control parameters
appropriate for your system. If you would like more information on PID
control, consult the Watlow-Anafaze Practical Guide to PID.

The control mode dictates how the controller responds to an input
signal. The control mode is different from the type of control output
signal (like analog or pulsed DC voltage). There are several control
modes available: On/Off, Proportional (P), Proportional and Integral
(PI), Proportional with Derivative, and Proportional with Integral and
Derivative (PID). P, PI, or PID control are necessary when process
variable (PV) cycling is unacceptable or if the process or setpoint (SP) is
variable.

NOTE

For any of these control modes to function, the loop
must be in automatic mode.

Control Modes

The next sections explain the different modes you can use to control a
loop.