Dual Output Control 4.8
Dual output control can be performed when two outputs are specified. The outputs may be
programmed for On-Off, Time Proportioning, or Current Proportioning, as applicable. To utilize
the Auto Tune feature, Output 1 must be programmed for proportional reverse action.
The output action is dependent upon the setpoint, the process value, and Tune mode parame-
ters. If two proportional outputs are selected, both output proportional bands will be biased so
that 0 % of output is seen when the process value equals setpoint. The output(s) can be
biased by the use of the Tune mode parameters FoP and SoP as shown below.
FIGURE 4-2
100%
Proportional
Output 1
First
Output
Position = X
The first output is programmed as a proportional reverse output and the second as a propor-
tional direct output. (See Glossary, page 68, for definitions of these terms). Dual propor-
tioning outputs are provided with separate proportional band; auto reset, rate, and cycle time
adjustments for each output.
Reverse
Direct
Acting Output
Acting Output
Control
Setpoint
+Y
-X
100%
Proportional
Output 2
Second
Output
Position = Y
P
Process
Value
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