P
AGE
40
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.
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 SPrd as shown below.
FIGURE 4-2
The first output is programmed as a proportional reverse output and the second as a propor-
tional direct output. (See Glossary, page 63, for definitions of these terms). Dual propor-
tioning outputs are provided with separate proportional band and cycle time adjustments for
each output.
100%
Proportional
Output 1
Reverse
Acting Output
Direct
Acting Output
100%
Proportional
Output 2
Control
Setpoint
First
Output
Position = X
Process
Value
+Y
-X
Spread = Y
