Instruction Manual
D200156X012
4194HA, HB, HC Controllers
July 2018
22
Section 4
4‐4‐
4194HB Proportional‐Plus‐Reset Controllers And 4194HC
Proportional‐Plus‐Reset‐Plus‐Rate Controllers
Adjustments for 4194HB and HC Controllers
This section includes descriptions of adjustments and procedures for prestartup and startup.
Location of adjustments is shown in figure 3‐1. To better understand the adjustments and overall operation of the
controller, refer to the principle of operation and the schematic diagrams (figures 4‐2 through 4‐6). Unless otherwise
noted, key numbers given in this section can be found in figure 6‐1.
When placing the controller into operation use the following procedure for adjustment. Refer to figure 3‐1 for
locations of adjustments.
Manual Set Point Adjustment
To adjust the set point, open the controller cover and move the set point indicator until the indicator is at the desired
value on the process differential pressure scale. Move the adjustment 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.
If the controller is equipped with the optional external or internal 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 indicator on a controller with remote set point. Doing so could damage the controller.
If the controller is equipped with the remote set point option, 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 Adjustment (PB ADJ)
Locate the proportional band adjustment. Rotate the adjustment until the desired value is beneath the PB ADJ white
indicator mark. Adjusting the proportional band has a minimal effect on the set point.
Changing Controller Action
Switch controller action from direct to reverse or vice‐versa by simply loosening the screws on the proportional band
indicator cover and pulling the cover outward so the proportional band adjustment can be rotated to the desired
action (figure 5‐2).