Proportional Band Adjustment (Pb Adj); Changing Controller Action; Reset Adjustment; Rate Adjustment - Emerson Fisher KC Series Instruction Manual

4195KA, KB, KC, and KS Controllers
W3439 / IL
Figure 4-2. Changing Controller Action on
4195KB and KC Series Controllers

Proportional Band Adjustment (PB ADJ)

The proportional band determines the controller
output sensitivity. The proportional band adjustment
is marked in percentages of process pressure
required to drive the controller from zero output to
full output.
To adjust the proportional band, open the controller
cover and locate the proportional band adjustment
(PB ADJ) knob. Rotate the knob until the desired
value is opposite the line on the proportional band
indicator cover.

Changing Controller Action

To change the controller action from direct to reverse
or vice versa, loosen the screws on the proportional
band indicator cover. Lift the cover out as shown in
figure 4-2 and rotate the proportional band
adjustment to the desired action. Setting the
proportional band to the values in the white portion
of the adjustment provides direct controller action;
setting proportional band in the black portion
provides reverse controller action.
Bourdon Tube or Capsular Element Controllers
for Positive or Compound Pressure
D For direct control action:
An increasing sensed pressure increases output
pressure.
D For reverse control action:
An increasing sensed pressure decreases output
pressure.
4-2
Capsular Element Controllers for Vacuum
Pressure
D For direct control action:
An increasing sensed vacuum increases output
pressure.
D For reverse control action:
An increasing sensed vacuum decreases output
pressure.
After changing the action, tighten the screws on the
proportional band indicator cover.

Reset Adjustment

To adjust reset, open the controller cover and locate
the RESET adjustment. Rotate the adjustment
clockwise to decrease the minutes per repeat or
counterclockwise to increase the minutes per repeat.
Increasing the minutes per repeat provides a slower
reset action.

Rate Adjustment

To adjust rate, open the controller cover and locate
the RATE adjustment. Rotate the adjustment
clockwise to decrease the minutes (less rate action)
or counterclockwise to increase the minutes (more
rate action).
Anti-Reset Windup (suffix letter F)
Adjustment
If the arrow on the relief valve points toward the
bottom of the controller case, as shown in figure 4-1,
the valve opens with increasing controller output
pressure. If the arrow points in the opposite
direction, the relief valve opens with decreasing
controller output pressure. Differential relief pressure
is factory set at 0.3 bar (5 psig). Maximum relief
pressure is 0.5 bar (7 psig). The minimum is 0.1 bar
(2 psig).
Turn the adjusting screw counterclockwise to
increase differential relief pressure, clockwise to
decrease it.
Instruction Manual
Form 5207
April 2007