Instruction Manual
D200158X012
4194S Controllers
July 2018
31
43. Repeat steps 35 through 42 until the output pressure snaps to supply pressure within
±
2 percent of set point at 5
and 95 percent on the process scale range. Then go to step 53.
44. For reverse acting controllers, adjust the proportional band knob to 5 percent reverse acting. Adjust the set point
manually or with remote set point pressure to 5 percent of the process scale range.
45. Carefully adjust the process differential pressure to 100 percent of the process scale range. Then, slowly decrease
the process differential pressure until the output pressure snaps to supply pressure. The output should snap to
supply pressure within
±
2 percent of set point.
46. If the output pressure snaps to supply pressure below 2 percent of set point, adjust flapper leveling screw number 1
counterclockwise (see figure 3-1 for location of screw). If the output pressure snaps to supply pressure above 2
percent of set point, adjust flapper leveling screw number 1 clockwise.
47. Repeat steps 44 through 46 until the output pressure snaps to supply pressure within
±
2 percent of set point. If the
tolerance cannot be obtained with the flapper leveling screw, go to step 51.
48. Adjust the set point manually or with remote set point pressure to 95 percent to the process scale range.
WARNING
In step 49, do not exceed the operating limits of the controller (refer to table 1-3). Personal injury or equipment damage
may result from overpressure.
49. Increase the process differential pressure until the output pressure snaps to zero. Then, slowly decrease the process
differential pressure until the output pressure snaps to supply pressure. The output should snap to supply pressure
within
$
2 percent of set point.
50. If the output pressure snaps to supply pressure within
±
2 percent of set point, go to step 53. If the output pressure
does not snap to supply pressure within
±
51. If the output pressure snaps to supply pressure below 2 percent of set point, adjust the set point beam shoe
(key 29) slightly toward the center of the nozzle pivot. If the output pressure snaps to supply pressure above 2
percent of set point adjust the set point beam shoe slightly away from the center of the nozzle pivot.
52. Repeat steps 44 through 51 until the output pressure snaps to supply pressure within
±
2 percent of set point at 5
and 95 percent of the process scale range; then go to step 53.
53. Install the controller assembly in the case. Slide the controller frame down to assure an O‐ring seal at the pressure
connections. Hold the frame in place.
54. Install and tighten the nine mounting screws that hold the controller assembly in place.
55. Refer to the Flapper Alignment procedures.
56. Replace the proportional band indicator cover (key 36) and tighten the two screws (key 6).
Flapper Flexure Pivot Assembly
Note
The following procedure requires that the controller be removed from the case. Perform steps 1 through 3 of the replacing case
and cover procedure.
1. Remove the two screws (key 6), and lift off the proportional band cover (key 36).
3. Remove the set point beam bias spring (key 28), refer to figure 4-5 for spring location.
