Emerson Fisher 4194HA Instruction Manual page 28

4194HA, HB, HC Controllers
July 2018
Flapper leveling screw numbers and adjustments are shown in figure 3‐1.
Provide a regulated process differential pressure to the differential pressure unit. Also, plug the controller output
connection and provide a regulated supply pressure to the controller. Do not exceed the normal operating pressure in
table 1‐4.
Note
4194HB and HC controllers with the anti‐reset windup option (suffix letter F) are supplied with two O‐rings (key 52,
figure 6‐1/CONTROLLER COMMON PARTS), valve cover (key 51, figure 6‐1/VIEW E, 4194HB controllers or VIEW E, 4194HC
controllers), and two machine screws (key 53, figure 6‐1/VIEW E, 4194HB controllers or VIEW E, 4194HC controllers). Use these
parts in the next step.
1. For 4194HB and HC controllers with the anti‐reset windup option (suffix letter F), remove the differential relief valve
(key 55, figure 6‐1/VIEW E, 4194HB controllers, Option F or VIEW E, 4194HC controllers, Option F). Install the two
O‐rings (key 52) and valve cover (key 51) provided with the controller. Secure the valve cover over the two O‐rings
with the two machine screws (key 53) also provided.
2. For a controller with manual set point, move the set point indicator to 50 percent of the scale range. For a controller
with remote set point (suffix letter M), adjust the remote set point pressure until the set point indicator is at 50
percent of the scale range.
3. Remove the two machine screws (key 6) and lift off the proportional band indicator cover (key 36).
4. Adjust the reset adjustment to 0.01 minute per repeat.
5. If the controller has rate (4194HC controllers), turn the rate adjustment to OFF.
6. If the controller has the external feedback option (available with a 4194HB controller only), shut off the supply
pressure, connect the controller output to the external feedback connection, and turn on the supply pressure. See
figure 2‐2 for the location of the output and external feedback connections.
7. Adjust the process differential pressure to 50 percent of the input range. If pressure is not available to pressure the
differential pressure unit to 50 percent of range, an alternate method is to disconnect link 1 at the drive arm and
tape the process indicator at 50 percent of the process differential pressure input range.
Note
In steps 8 through 12, the controller output will not stabilize because of the high controller gain. The controller output gauge is
adequate to check the output pressure during this procedure.
8. Set the proportional band between DIRECT and REVERSE.
9. Adjust flapper leveling screw number 2 until the controller output is relatively stable at any value within the output
range.
10. Adjust the proportional band to 20 percent direct acting. Adjust flapper leveling screw number 3 until the controller
output is relatively stable at any value within the output range.
11. Adjust the proportional band to 20 percent reverse acting. Adjust flapper leveling screw number 1 until the
controller output is relatively stable at any value within the output range.
12. Repeat steps 8 through 11 until the controller output remains relatively stable with no adjustments of the flapper
leveling screws.
Note
Steps 13 through 19 check the flapper alignment.
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Instruction Manual
D200156X012