Appendix B: Manual Tuning - Omega CN4420 Series Manual

APPENDIX B
Manual Tuning
Tune the controller if any of the following occurs:
• Installation in a new system
• Installation replacement in an existing system
• The input sensor is relocated or changed
• The output device is relocated or changed
• The setpoint is significantly changed
• Any other condition that will alter the dynamics of the system
Proportional Band
The proportional band is a band around the setpoint of the controller
where the output is between 0% and 100%. The percentage of output is
proportional to the amount of error between the setpoint variable (SV)
and the process variable (PV). Outside of the proportional band the out-
put is either 0% or 100%
The proportional band on the controller is equidistant from the main set-
point as illustrated below.
Reverse Action
Direct Action
PB
PB
100%
100%
Output
Output
0%
PV
0%
PV
Main Setpoint
Main Setpoint
Note: PB = Proportional Band
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