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4194S Controllers
July 2018
5. Lift out the capsular element assembly by holding the plate (key 77), travel stop (key 83), or pedestal (key 81).
6. Align the replacement capsular element assembly over the mounting screw holes. Install and tighten the mounting
screws.
7. Reconnect link 1 (key 90) to the pointer subassembly in the same hole noted in step 3.
8. Reconnect the process pressure connections.
9. Apply process differential pressure to the controller, and check for leaks.
10. Refer to the Maintenance Calibration procedure.
Maintenance Calibration
Note
Perform full maintenance calibration (includes all procedures) upon completion of maintenance procedures. If only zero and span
or linearity adjustments are required, use only those sections. Key numbers are referenced in figures 5-1 and 5-2. Adjustments are
shown in figure 3-1. After Maintenance Calibration, perform the Flapper Alignment procedures if directed to do so. Otherwise, go
to the appropriate prestartup instructions in the controller operation procedures.
WARNING
Refer to the Maintenance WARNING on page 21.
Precalibration Procedures
1. Set the proportional band adjustment to 5 percent direct acting. Adjust the set point to 100 percent of the process
scale range.
2. Remove the tie bar (key 97).
Aligning the Drive Bracket Assembly
1. Loosen the set screw in the hex nut (key 86) of the drive bracket assembly (key 84)
2. Loosen the screw (key 98) that holds the guide flexure to the tab on the mounting plate.
3. Adjust the input pressure to 75 percent of full differential pressure span.
4. Slide the drive bracket assembly (key 84) along the diaphragm capsule extension (key 82) until the guide flexure is
aligned with the center of pivot A (key 78).
5. Tighten the set screw in the hex nut to fasten the drive bracket assembly in that position.
Setting the Travel Stops
1. Loosen the set screw in the travel stop nut (key 86).
CAUTION
Make sure the loose travel stop nut does not bind up on the diaphragm capsule extension when pressurizing the capsules.
Damage to the capsules may result.
42
Instruction Manual
D200158X012
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