Instruction Manual
D200156X012
4194HA, HB, HC Controllers
July 2018
27
15. If the error is greater than
±
1 percent, repeat steps 3 through 14.
16. Perform the flapper alignment procedure.
Remote Set Point (suffix letter M) Zero‐and‐Span Calibration
Refer to figure 3‐1 for location of adjustments. Refer to figures 6‐1 and 6‐3 for key number locations.
Note
Any adjustment of the remote set point span adjustment screw will require readjustment of the set point zero adjustment screw.
See 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.
1. Remove two screws (key 6) and lift off the proportional band indicator cover (key 36).
2. Set the proportional band adjustment between DIRECT and REVERSE.
3. Apply remote set point pressure equal to the low limit of the set point input range. Note the position of the set
point indicator. Loosen the set point zero adjustment locking screw and adjust the zero adjustment screw (figure
5‐6) until the set point indicator aligns with the lowest scale limit.
Properly align the set point indicator with the low scale limit. Tighten the zero adjustment locking screw.
4. Adjust the remote set point pressure to the upper limit of the input span. Note whether the indication is above or
below the upper limit of the process scale.
5. Adjust the span screw (figure 3‐1) as follows: Clockwise to increase span for a low indication; counterclockwise to
decrease span for a high indication. Adjust the span screw to correct one‐half the error.
6. Repeat steps 3 through 5 until the error is eliminated.
7. Adjust the remote set point pressure to 50 percent of the remote set point range.
8. Make sure the remote set point indicator is within
±
2 percent of the mid‐scale mark, then proceed with step 9. If the
set point indicator is not within
±
2 percent, proceed to the Remote Set Point Maintenance Calibration procedure in
9. Loosen the zero adjustment locking screw. Adjust the zero screw to correct for half the error.
10. Adjust the remote set point pressure to the lower and upper range limits. Make sure the set point indicator is within
±
1 percent.
11. Install the proportional band indicator cover (key 36) and tighten two screws (key 6).
12. If necessary, proceed to the process indicator zero‐and‐span calibration procedure in this section. Otherwise,
proceed to the flapper alignment procedure in this section.
Flapper Alignment
Note
Perform the process indicator zero‐and‐span calibration procedure and, if necessary, the remote set point calibration procedure
before the flapper alignment.
If the controller has the external feedback option, connect the external feedback connection to the controller output connection.
