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4660 Pressure Pilot
May 2014
1. Remove the case cover screw (key 5) and the case cover (key 3).
2. Lift the end of the flapper off the nozzle beam approximately 19 mm (0.75 inch) by moving the opposite end of the
flapper clockwise for a slight rotation.
CAUTION
Be careful not to force the flapper such that the spring (key 18) will become damaged.
3. Release the upper end of the flapper such that the flapper will snap back and contact the nozzle beam.
4. Replace the case cover, and attach it with the case cover screw.
Startup
Verify that the desired high and/or low set point pressures have been set. Refer to the Mounting section for the desired
pilot installation procedures.
Reduce the external process pressure source to zero and disconnect the source from the process
Performance
The performance characteristics shown in figure 6 illustrate several important functional parameters.
Figure 6. Performance Characteristics
100%
OUTPUT
PRESSURE
A2897‐2
S
and S
represent the low and high set points, respectively. The set range is 3 to 97 percent of the Bourdon tube
L
H
rating. However, with a single high‐low unit or a high‐only/low‐only pair, there is a limit on how close to each other the
set points can be adjusted. This limit is defined as set point DP
Trip‐to‐reset is the combined effect of pilot dead band and hysteresis. After the pilot has tripped, it will automatically
reset when the process pressure returns to the set range. However, full output is not instantaneous. The difference
between the set point and reset to full output is the trip‐to‐reset zone. This parameter is also a function of the Bourdon
tube rating as shown in figure 6.
Finally, repeatability is the switch point deviation around the set point as a percentage of the Bourdon tube rating.
16
TRIP‐TO‐
RESET ZONE
SET POINT
ΔP
MIN
PROCESS PRESSURE
PERCENT OF BOURDON TUBE RATING
CONSTRUCTION
Set Point
DP
10
Single High‐Low Unit
High‐Only/Low‐Only Pair
1. 5000 and 7500 psig Bourdon tubes are 15 percent of Bourdon tube rating.
and is shown as S
and S
MIN
L'
Instruction Manual
D200163X012
Trip‐to‐
Repeatability
Reset Zone
MIN
(1)
≤1.5
≤0.25
3
.
H'
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