Watlow Series D8 - Manual (Page 129)

Doc. 0600-3120-2000 Watlow Anafaze 111
5
Tuning and Control
This chapter describes the different methods of control avail-
able with the D8. This chapter covers control algorithms, con-
trol methods, PID control, starting PID values and tuning
instructions to help appropriately set control parameters in the
D8 system.
For more information about PID control, consult the Watlow
Anafaze Practical Guide to PID
.
Control Algorithms
This section explains the algorithms available for controlling
a loop.
The control algorithm dictates how the controller responds to
an input signal. Do not confuse control algorithms with con-
trol output signals (for example, analog or pulsed dc voltage).
There are several control algorithms available:
•
On/off
• Proportional (P)
• Proportional and integral (PI)
• Proportional with derivative (PD)
• Proportional with integral and derivative (PID)
P, PI or PID control is necessary when process variable cy-
cling is unacceptable or if the load or set point varies.
NOTE! For any of these control algorithms to func-
tion, the loop must be in automatic mode.