Instruction Manual
D200158X012
4194S Controllers
July 2018
11
Section 3
Controller Operation
33-3-
Operating Information
This section includes descriptions of adjustments and procedures for prostrate and startup procedures. Location of
adjustments are shown in figures 3-1 and 3-2. To better understand the adjustments and overall operation of the
controller, refer to the Principle of Operation section and the schematic diagrams, figures 3-4 and 3-5.
Adjustments
Manual Set Point
To adjust the set point, open the controller cover and move the set point adjustment until the pointer indicates the
desired value of pressure on the process pressure scale. Move the adjustment to the right to increase the set point, and
to the left to decrease it. Adjusting the set point does not affect the differential gap setting.
Remote Set Point (Option M)
CAUTION
Do not move the set point adjustment manually on controllers with remote set point. Doing so could damage the
controller.
If the controller is equipped with the remote set point option (see figure 3-2), vary the remote set point pressure to
change the set point. Increase the pressure to increase the set point, and decrease the pressure to decrease the set
point.
Proportional Band (Differential Gap)
The proportional band knob adjusts the width of the gap between switching points. Rotate the proportional band
knob until the desired setting is opposite the line on the proportional band indicator cover.
Changing Controller Action
Controller action can be switched from direct to reverse or vice versa by simply loosening the screws on the
proportional band indicator cover and moving the cover out so the proportional band knob can be rotated to the
desired action. The white portion of the adjustment enables direct controller action; the black portion enables reverse
controller action.
Auto/Manual Switching (Option E)
Refer to figure 5-4 if the controller has the auto/manual option. Two balance methods are available to equalize the
manual output with the controller pressure. To switch from automatic to manual mode, carefully adjust the loader
knob until the metal ball inside the plastic tube moves into the switching zone. Then move the automatic/manual
switch to MANUAL. Turn the loader knob clockwise to increase the controller output or counter‐clockwise to decrease
it. To switch from manual to automatic mode, adjust the set point manually or with remote set point pressure to move
the ball into the switching zone. Turn the switch to AUTOMATIC, and move the set point adjustment to control the
output.