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