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W6391 / IL
Section 3
4194A Series
Proportional-Only Controllers
Adjustments for 4194A Series
Controllers
This section includes descriptions of adjustments and
procedures for prestartup, startup, and calibration. Ad-
justment locations are shown in figures 3-1 and 3-3. To
better understand the adjustments and overall control-
ler operation, refer to the principle of operation section
and to the schematic diagrams in figures 3-4 and 3-5.
Unless otherwise noted, key numbers given in this
section are found in figure 5-21.
Manual Set Point Adjustment
Adjust the set point by moving the set point indicator
until the line on the set point indicator is over the de-
sired value on the process differential pressure scale.
Move the indicator to the right to increase the set
point, and to the left to decrease it. Adjusting the set
point does not affect the proportional band setting.
Figure 3-1. 4194A Series Controller Adjustment Locations
4194A, B, and C Series
W3679 / IL
SET POINT
INDICATOR
PROCESS POINTER
PROPORTIONAL BAND
ADJUSTMENT
PROPORTIONAL BAND
INDICATOR COVER
OUTPUT PRESSURE
GAUGE
If the controller is equipped with the optional internal or
external set point adjustment, turn the adjustment
knob clockwise to increase the process set point and
counterclockwise to decrease the process set point.
Remote Set Point (suffix letter M)
Adjustment
CAUTION
Do not manually move the set point in-
dicator on controllers with remote set
point. Manually moving the set point in-
dicator could damage the controller.
If the controller is equipped with remote set point (suf-
fix letter M), vary the remote set point pressure to
change the set point. Increase the pressure to in-
crease the set point, and decrease the pressure to
decrease the set point.
Proportional Band Adjustment (PB ADJ)
The proportional band determines the output sensitiv-
ity of the controller. The proportional band adjustment
is marked in percentages of process differential pres-
sure required to drive the controller from zero output to
full output.
METAL BALL
SWITCHING ZONE
INDICATOR
LOADER KNOB
AUTO/MANUAL
SWITCH
3–1
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