PPC-2000 User’s Guide
Chapter 3: Operating with AnaWin 3
Doc.# 30002-00 Rev 2.3
Watlow Anafaze
107
Figure 3.8
Sample Application Using
Cascade Control
For cascade control the inner TC is selected as the
PV Source
for
the primary channel, and the outer TC is selected as the
PV
Source
for the secondary channel. The secondary channel’s
output is used to control the heater.
An engineer familiar with the process has determined that as
the temperature of the inner (primary) TC drops from 150°F to
140°F, the set point of the secondary channel should rise from
150°F to 190°F.
list the
parameter settings for the primary and secondary channels.
The PID parameters of the primary channel must be tuned to
produce the desired effect on the secondary channel’s set point.
The primary channel typically uses
proportional only
control.
Disabling the integral and derivative components of PID
makes the secondary set point a predictable function of the
primary channel’s process variable.
The proportional band is selected so the set point of the
secondary channel has the desired relationship to the process
variable of the primary channel. In this application, the
proportional band of the primary channel is set to 10°F.
Table 3.9
Primary Channel Parameter
Settings
Parameter
Setting
Description
PV Source
PPC1:AI 1.1
The inner TC is selected for the primary channel.
Set Point
150°F
The desired temperature at the inner TC.
Heat Prop Band
10
As the input drops 10°F, the output increases to 100%.
Heat Integral
0
Only proportional control is used.
Heat Derivative
0
Only proportional control is used.
Heat Output Dest
PPC1:Soft Bool
The primary output must be enabled, but is not used to drive
a load.
Power
Control
Tank
Heater
PPC
Channel 2 Heat Output
Inner TC Channel 1 Input
Outer TC Channel 2 Input
Outer
Inner
inner
outer
outer
outer
Summary of Contents for Anafaze PPC-2000
Page 2: ......
Page 14: ...Table of Contents PPC 2000 User s Guide viii Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 24: ...List of Tables PPC User s Guide xviii Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 36: ...Chapter 1 Overview PPC 2000 User s Guide 12 Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 112: ...Chapter 2 Hardware Installation PPC 2000 User s Guide 88 Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 184: ...Chapter 4 Troubleshooting PPC 2000 User s Guide 158 Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 296: ...Chapter 7 Specifications PPC 2000 User s Guide 268 Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 310: ...Appendix A Modbus Protocol PPC 2000 User s Guide 282 Watlow Anafaze Doc 30002 00 Rev 2 3...
Page 311: ...Doc 30002 00 Rev 2 3 Watlow Anafaze 283 B Appendix B Declaration of Conformity...
Page 319: ...PPC 2000 User s Guide Glossary Doc 30002 00 Rev 2 3 Watlow Anafaze 291...
Page 320: ...Glossary PPC 2000 User s Guide 292 Watlow Anafaze Doc 30002 00 Rev 2 3...
