Configuration
3.4 Tuning Set Up Group
Introduction
Tuning consists of establishing the appropriate values for the tuning constants you are
using so that your controller responds correctly to changes in process variable and
setpoint. You can start with predetermined values but you will have to watch the system
to see how to modify them. The Accutune feature automatically selects Gain, Rate, and
Reset on demand.
ATTENTION
Because this group contains functions that have to do with security and lockout, we recommend
that you configure this group last, after all other configuration data has been loaded.
Function Prompts
Table 3-4 TUNING Group Function Prompts
Function Prompt
Lower Display
Selections or
Range of Setting
Upper Display
Parameter
Definition
PROP BD
or
GAIN
0.1 to 9999 %
or
0.001 to 1000
PROPORTIONAL BAND (simplex) is the percent of
the range of the measured variable for which a
proportional controller will produce a 100 % change
in its output.
GAIN is the ratio of output change (%) over the
measured variable change (%) that caused it.
G =
100%
PB%
where PB is the proportional band (in %)
If the PB is 20 %, then the Gain is 5. And, at those
settings, a 3 % change in the error signal (SP-PV)
will result in a 15 % change in the controller's output
due to proportional action. If the Gain is 2, then the
PB is 50 %.
Also defined as "HEAT" Gain on Duplex models for
variations of Heat/Cool applications.
The selection of Proportional Band or Gain is made
in the CONTROL parameter group under prompt
PBorGAIN.
RATE MIN
0.00 to 10.00 minutes
RATE action, in minutes, affects the controller's
output whenever the deviation is changing; and
affects it more when the deviation is changing faster.
Also defined as "HEAT" Rate on Duplex models for
variations of Heat/Cool applications.
40 UDC3200 Universal Digital Controller Product Manual 12/04
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