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General pid constants by application, Table 4.4—general pid constants 87 – Watlow CPC400 User Manual

Page 101

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CPC400 Series User’s Guide

Chapter 4: Tuning and Control

Doc. 0600-2900-2000

Watlow Anafaze

87

General PID Constants by Application

This section gives PID values for many applications. They
are useful as control values or as starting points for PID
tuning.

Proportional Band Only (P)

Set the proportional band to seven percent of the set point.
(Example: Set point = 450, proportional band = 31).

Proportional with Integral (PI)

Set the proportional band to ten percent of set point.
(Example: Set point = 450, proportional band = 45).

Set integral to 60.

Set derivative off.

Set the output filter to 2.

Proportional and Integral with Derivative (PID)

Set the proportional band to ten percent of the set
point.
(Example: Set point = 450, proportional band = 45).

Set the integral to 60.

Set the derivative to 15 percent of the integral.
(Example: Integral = 60, derivative = 9).

Set the output filter to 2.

Table 4.4 shows general PID constants by application.

Table 4.4

General PID Constants

Application

Proportional

Band

Integral

Derivative

Filter

Output

Type

Cycle

Time

Action

Electrical heat
with solid-state
relays

50

°

60

15

4

DZC

-

Reverse

Electrical heat
with electrome-
chanical relays

50

°

60

15

6

TP

20

Reverse

Cool with sole-
noid valve

70

°

500

90

4

TP

10

Direct

Cool with fans

10

°

Off

10

4

TP

10

Direct

Electric heat
with open heat
coils

30

°

20

Off

4

DZC

-

Reverse

Gas heat with
motorized
valves

Set Point>1200

60

°

100

°

120

240

25

40

8

Analog

-

Reverse