Page 1
Instruction Manual
Form 1446
June 1994
2502 Series
250
2 S
erie
s L
evel-Trol C
Contents
Introduction
Scope of Manual 2.
Description 2
Specifications 2
Controller Action 2.
Installation%2
249 Series Sensors 2.
Uncrating 4
Controller Orientation 4.
Mounting Caged Sensors 4.
Mounting Cageless Sensors 5.
Side-Mounted Sensor 7.
Top-Mounted Sensor 7.
Special Constructions 7.
Temperature-Compensated Displacer 7.
Piezometer Ring 8.
Regulator Supply Pressure 8.
Prestartup Checks
Adjustments 10
Level Set Adjustment 10.
Proportional Band Adjustment 10.
Reset Adjustment 10.
Differential Relief Adjustment 10.
Calibration
Precalibration Requirements 11.
Wet Calibration 11.
Dry Calibration 11.
Controller and Torque Tube Arm Disassembly 11
Determining Suspended Weight for Calibration 12
Calibration Procedure 12.
Startup
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ontroller
2.
W3121-3/IL
9.
Maintenance
Troubleshooting 16
Removing Controller from Sensor 16.
Changing Mounting Method 18.
11
13
Installing Controller on Sensor 19.
Changing Proportional, Reset, or
Differential Relief Valve 19.
Testing Relay Dead Band 19.
Changing Relay 20.
Replacing Bellows 20.
Reversing Action 20.
Disassembling Relay 20.
Parts Ordering
TYPE 2502 CONTROLLER
TYPE 249B SENSOR
Figure 1. Type 2502 Controller Mounted on
Type 249B Sensor
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15.
21.
Principle of Operation
Type 2502 Controller 15.
Type 2502F Controller with Reset Relief Valve 15.
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13.
Parts Kits
Parts List
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21.
21.
D200126X012
Page 2
2502 Series
Introduction
Scope of Manual
This instruction manual provides installation, operating, calibration, maintenance procedures for 2502 Series pneumatic controllers (figure 1) used in combination with 249 Series level sensors.
This manual does not include regulator or sensor
installation or maintenance procedures. For this information, refer to the instruction manual for the appropriate regulator and 249 Series level sensor.
Only personnel qualified through training or experience
should install, operate, and maintain this controller. If
there are any questions concerning these instructions
contact your Fisher Controls sales office or sales representative before proceeding.
Description
The Type 2502 Level-TrolR Controller described in
this manual provides proportional-plus-reset and proportional-plus-reset-with-anti-reset-windup control. The
controller output is a pneumatic signal that operates a
final control element. These controllers are designed
to control liquid level, the level of interface between
two liquids, or density (specific gravity). Each unit consists of a 249 Series liquid level sensor and a 2502
Series pneumatic controller.
AMBIENT TEMPERATURE (_C)
–18 –10
1100
_
800
400
0
USE INSULATOR (CAUTION! IF AMBIENT DEWPOINT IS
ABOVE PROCESS TEMPERATURE, ICE FORMATION MAY
PROCESS TEMPERATURE ( F)
CAUSE INSTRUMENT MALFUNCTION AND REDUCE
INSULATOR EFFECTIVENESS.)
–20 –29
0 20 40 60 80 100 120 140 160
–18 –10
1100
_
800
400
NO INSULATOR NECESSARY
0
USE INSULATOR (CAUTION! IF AMBIENT DEWPOINT IS
ABOVE PROCESS TEMPERATURE, ICE FORMATION MAY
PROCESS TEMPERATURE ( F)
CAUSE INSTRUMENT MALFUNCTION AND REDUCE
INSULATOR EFFECTIVENESS.)
–20 –29
0 20 40 60 80 100 120 140 200
B1413-1/IL
NOTE: FOR SERVICE BELOW –20_F (–29_C) CONTACT FACTORY.
01020
HEAT INSULATOR
REQUIRED
NO INSULATOR NECESSARY
AMBIENT TEMPERATURE (_F)
01020
HEAT INSULATOR
REQUIRED
AMBIENT TEMPERATURE (_C)
AMBIENT TEMPERATURE (_F)
30 40 50 60 70
30 40 50 60 70
TOO
HOT
71
593
500
400
300
200
100
0
80 90
TOO
HOT
180160
Figure 2. Guidelines for Use of Optional
Heat Insulator Assembly
plied reverse-acting unit has the suffix letter R added
to the type number.
_
PROCESS TEMPERATURE ( C)
93
593
500
400
300
200
100
0
Refer to the Principle of Operation section for a more
comprehensive discussion of how the Type 2502
pneumatic controller operates.
Specifications
Table 1 gives general specifications for the Type 2502
Series Controllers.
Controller-Sensor Action
The following controller description is for right-hand
mounting. Left-hand mounting produces an output signal with the opposite action. Figure 4 shows cage
head mounting positions.
For right-hand mounting:
S Direct Action--Increasing liquid or interface level, or
density, increases the output signal.
S Reverse Action--Decreasing liquid or interface level,
or density, increases the output signal. A factory-sup-
Installation
The 2502 Series controllers are used in combination
with 249 Series sensors, and unless ordered separately, the controller will be attached to the sensor.
249 Series Sensors
D The Type 249, 249B, 249C, 249K, 249L, and
249N, sensors side-mount on the vessel with the displacer mounted inside a cage (caged) outside the vessel.
D The Type 249BP and 249CP sensors top-mount
on the vessel with the displacer hanging down into the
vessel (cageless).
D The Type 249V sensor side-mounts on the ves-
sel with the displacer hanging out into the vessel
(cageless).
External sensors provide more stable operation than
do internal sensors for vessels with internal obstructions or considerable internal turbulence.
2
Page 3
Table 1. Specifications
2502 Series
Available Configurations
Type 2502: A direct-acting controller which pro-
vides proportional-plus-reset control
Type 2502C: A Type 2502 with a level indicator
assembly
Type 2502F: A Type 2502 with a differential relief
valve
These type numbered products are also available with reverse action. For example, Type
2502R, Type 2502CR, and 2502FR
Input Signal
(1)
Liquid Level or Liquid-to-Liquid Interface Level:
From 0 to 100 percent of displacer length—standard lengths for all sensors are 14 inches (356 mm)
or 32 inches (813 mm). Other lengths available depending on sensor construction
Liquid Density: From 0 to 100 percent of displacement force change obtained with given displacer
volume—standard volumes are 60 inches3 (980
cm3) for Types 249C and 249CP sensors, or 100
inches3 (1640 cm3) for most other 249 Series sensors; other volumes available depending on
construction
Output Signal
(1)
3 to 15 psig (0.2 to 1.0 bar) or 6 to 30 psig (0.4 to
2.0 bar)
Action: Field reversible between direct (increasing
liquid or interface leel or specific gravity increases
output pressure) and reverse (increasing liquid or
interface level or specific gravity decreases output
pressure)
band setting of 0 or 200 percent
Maximum:
27 scfh (0.72 m3/h) at proportional band
setting of 100 percent
At 35 psig (2.4 bar)
Minimum:
7 scfh (0.2 m3/h) at proportional band
setting of 0 or 200 percent
Maximum:
42 scfh (1.1 m3/h) at proportional band
setting of 100 percent
Performance
Hysteresis: 0.6 percent of output pressure change
at 100 percent of proportional band
Repeatability(1): 0.2 percent of displacer length or
displacement force change
Dead Band(1): 0.05 percent of proportional band or
span
Typical Frequency Response
(1)
: 4 Hz and 90-de-
gree phase shift at 100 percent of proportional band
with output piped to typical instrument bellows using
20 feet (6.1 meters) of 1/4 inch (6.4 mm) tubing
Ambient Temperature Error: 1.5 percent of out-
put pressure change per 50_F (28_C) of temperature change at 100 percent of proportional band
when using sensor with standard-wall N05500
(K-Monel
Reset
(4)
) torque tube with 249 Series sensors
(1)
: Adjustable from 0.01 to 74 minutes per
repeat (100 to 0.01 repeats per minute)
Differential Relief (Type 2502F and 2502FR Controllers Only): Adjustable from 2 to 7 psi (0.1 to
0.48 bar differential) to relieve excessive difference
between proportional and reset pressures. Differential relief can be switched between rising output
pressure and falling output pressure.
Area Ratio of Relay Diaphragms
3:1
Supply Pressure Requirement
(2)
20
psig (1.4 bar) for 3 to 15 psig (0.2 to 1.0 bar)
output signal or 35
(2)
psig (2.4 bar) for 6 to 30 psig
(0.4 to 2.0 bar) output signal
Maximum Supply Pressure
50 psig (3.4 bar)
Supply Pressure Consumption
At 20 Psig (1.4 bar)
Minimum:
1. Term defined in ISA Standard S51.1-1979.
2. Control and stability may be impaired if this pressure is exceeded.
3. Scfh=standard cubic feet per hour at 60_F and 14.7 psia (normal cubic meters per hour (m3/hr) at 0_C and 1.01325 bar).
4. K-Monel is a mark owned by Inco International.
4.2 scfh
(3)
(0.11 m3/h) at proportional
Standard Tubing Connections
1/4 inch (6.4 mm) NPT female
Maximum Working Pressures (Sensors Only)
Consistent with aplicable ANSI pressure/temperature ratings
Operative Ambient Temperatures
Standard Construction: 40 to 160_F (40 to
71_C)
High Temperature Construction: 0 to 220_F
(18 to 104_C). See figure 2
3
Page 4
2502 Series
WARNING
When replacing the sensor assembly,
the displacer may retain process liquid
or pressure. Personal injury or property
damage due to sudden release of pressure, contact with hazardous liquid, fire,
or explosion can be caused by puncturing, heating, or repairing a displacer
that is retaining process pressure or liquid. This danger may not be readily apparent when disassembling the sensor
or removing the displacer. Before disassembling the sensor or removing the
displacer, observe the more specific
warning provided in the sensor instruction manual.
Uncrating
Unless ordered separately, the controller will be attached to the sensor when shipped. Carefully uncrate
the assembly.
CAUTION
A thin-wall torque tube has a T stamped
on the sensor end flange (not visible unless the controller/transmitter is removed from the sensor). For sensors
with a thin-wall torque tube, always support the displacer if the travel stop must
be removed.
Note
Caged sensors have a rod and block
installed on each end of the displacer to
protect the displacer in shipping. Remove these parts before installing the
sensor to allow the displacer to function
properly.
Caged sensors will be shipped with the displacer
installed in the cage. If the sensor is ordered with a
tubular gauge glass, the gauge glass will be crated
separately and must be installed at the site. Be certain
that the cage equalizing connections are not plugged
with foreign material.
ADJUSTING
PRESSURE
REGULATOR
1/4”-18 NPT
OUTPUT
CONNECTION
CD1700-E
A1909-1/IL
LOCKNUT
VENT
Figure 3. Pressure Connections
SCREW
1/4”-18 NPT
SUPPLY
CONNECTION
FILTER WELL
DRAIN VALVE
(12.7 mm) hexagon wrench to unscrew the damping
plate. For flanged connections, use a screwdriver to
pry the damping plate out of the flange.
A cageless sensor is shipped with the displacer separated from the sensor assembly. A displacer longer
than 32 inches (813 mm) is crated separately. A shorter displacer is crated with the sensor, but is not attached to the displacer rod. Inspect the displacer and
replace if it is dented. A dent may reduce the pressure
rating of the displacer.
Controller Orientation
A controller is to be mounted with the vent opening
pointing downward as shown in figure 3. This orientation is necessary to ensure draining of accumulated
moisture. The controller is attached to the sensor in
one or the other of the mounting positions shown in
figure 4: Right hand (with the case to the right of the
displacer when looking at the front of the case) or left
hand (with the case to the left of the displacer). The
mounting position can be changed in the field if required; refer to the appropriate sensor manual for instructions. Changing this mounting position will change
controller action from direct to reverse, or vice versa.
All caged sensors have a rotatable head. That is, the
controller may be positioned at any of eight alternate
positions around the cage as indicated by the numbers
1 through 8 in figure 4. To rotate the head, remove the
head flange bolts and nuts and position the head as
desired.
Mounting Caged Sensor
CAUTION
A caged sensor has a damping plate installed in the
lower screwed or flanged connection to provide more
stable operation. If the process liquid could clog the
plate opening with sediment, then remove the damping plate. For screwed connections, use a 1/2-inch
4
The cage must be installed plumb so
that the displacer does not touch the
cage wall. Should the displacer touch
the cage wall, the unit transmits an erroneous output signal.
Page 5
2502 Series
AH9150–A
A2613–2/IL
Figure
4. Cage Head Mounting Positions
Note
If the controller is not mounted on the
sensor, refer to the Installing Controller
on Sensor section. That section also
provides instructions for adding a heat
insulator to a unit. If a temperature-compensating displacer or piezometer ring
is used, refer to the special installation
procedures in this section before proceeding.
Cage connections will normally be either 1-1/2 or
2-inch (38.1 to 50.8 mm) screwed or flanged. Figure 5
shows the combinations. It is recommended that a
drain be installed between the cage and shutoff or
hand valve whenever the bottom cage line has a liquid-trapping low point.
Mount the cage by running equalizing lines between
the cage connections and the vessel (figure 6). On
liquid or interface level applications, position the sensor so that the line marked FLOAT CENTER on the
cage is located as close as possible to the center of
the liquid level or interface level range being measured.
A1271–2/IL
Figure 5. Cage Connection Styles
For liquid or interface level applications, it is advantageous to install a gauge glass either on the vessel, or
on the sensor cage (if the cage is tapped for a gauge).
With flanged connections, use standard gaskets or
other flat-sheet gaskets compatible with the process
liquid. Spiral wound gaskets without compression-controlling centering rings cannot be used for flanged connections.
Mounting Cageless Sensor
CAUTION
If a stillwell is used, it must be installed
plumb so that the displacer does not
touch the wall of the stillwell. Should
the displacer touch the wall while the
unit is in service, the unit will transmit
an erroneous output signal.
Since the displacer hangs inside the vessel, it is advisable to provide a stillwell around the displacer when
the liquid is in a state of continuous agitation and excessive turbulence can be expected.
5
Page 6
2502 Series
CENTER
OF
LIQUID OR
INTERFACE
LEVEL
SHUTOFF
VALVES
VENT
EQUALIZING
LINE
DRAIN
DF5379-A
A6771/IL
Figure
6. Caged Sensor Mounting
CAUTION
Since a displacer used in an interface
level or a density application must be
completely submerged during operation, obtaining desired controller sensitivity requires the use of either a thinwall torque tube or an overweight
displacer, or both. An overweight displacer cannot be used for any service
except those conditions for which it was
specified.
Note
W0645-1
TOP
MOUNTED
If the controller is not mounted on the
sensor, refer to the Installing Controller
on Sensor section. That section also
provides instructions for adding a heat
insulator to a unit. If the sensor has a
temperature-compensated displacer or
piezometer ring, refer to the special
constructions procedures in this section before proceeding.
Attach a cageless sensor to a flanged connection on
the vessel as shown in figure 7. For interface or liquid
level applications, install a gauge glass on the vessel.
6
CF5380-A
A3893/IL
Figure
7. Cageless Sensor Mounting
CAUTION
If the displacer is to be inserted into the
vessel before being attached to the displacer rod, provide a suitable means of
Page 7
supporting the displacer to prevent it
from dropping into the vessel and suffering damage.
To help support a Type 249BP or 249CP displacer,
install the displacer stem and stem end piece, or a
threaded rod, into the 1/4 inch-28 UNF threaded hole
in the displacer spud or stem end piece (figure 8). On
the Type 249BP with optional travel stop, the stem
end piece pins will secure the displacer as long as the
travel stop plate is installed and the sensor head is in
position.
Side-Mounted Sensor
If a stillwell is required (figure 7), the displacer must be
attached to the displacer rod from inside the vessel.
Connect the displacer as shown in figure 8, locking the
assembly with the cotter spring provided. If a stillwell
is not required, the displacer can be attached to the
displacer rod before mounting the sensor to the vessel
connection. The displacer may then be swung out horizontally for insertion into the vessel. If an extension is
used between the displacer spud and the displacer
stem end piece, make sure the nuts are tight at each
end of the displacer stem extension. Install and tighten
suitable bolting or cap screws in the flanged connection to complete the installation.
2502 Series
DISPLACER
STEM
END PIECE
DISPLACER
STEM
EXTENSION
W0229-1A/IL
DISPLACER
SPUD
W0228-1A/IL
Figure 8. Displacer/Displacer Rod Connections
COTTER SPRING
LOCKING NUTS
DISPLACER SPUD
COTTER SPRING
DISPLACER ROD
DISPLACER ROD
Top-Mounted Sensor
Figure 7 shows the installation of a top-mounted cageless sensor. The displacer may be attached to the displacer rod before installing the sensor on the vessel.
Where the displacer diameter is small enough, it may
be desirable to install a long or sectionalized displacer
through the sensor head access hole after the sensor
is installed on the vessel. Connect the displacer as
shown in figure 8, locking the assembly with the cotter
springs provided. If a stem is used between the displacer as shown in figure 8, lock the assembly with the
cotter springs provided. If a stem is used between the
displacer spud and the stem end piece, make sure the
nuts are tight at each end of the stem. Install and tighten suitable cap screws in the flanged connection to
complete the installation.
Special Constructions
Temperature-Compensated Displacer
Some sensors use a temperature-compensated displacer (figure 9). This displacer is appropriate for density applications that do not tolerate specific gravity
changes due to temperature. The displacer must be
filled with the liquid to be measured, or with a liquid of
equal expansion coefficient. In service, the displacer
A0746–1/IL
Figure
9. Temperature-Compensated Displacer
7
Page 8
2502 Series
expands and contracts the same amount as the measured liquid to nullify signal changes that would be
caused by temperature changes.
This type of displacer is shipped in a separate carton
but crated with the rest of the assembly. See the appropriate sensor manual for filling instructions.
Piezometer Ring
A piezometer ring (figure 10) is used when it is desirable to measure the specific gravity of a liquid in a
flowing line, and when the liquid velocity exceeds two
feet/minute (10 mm/second) past the displacer in the
cage. The piezometer ring reduces the velocity effects
caused by liquid passing through the displacer cage.
To install this type of sensor, connect a line to the
cage inlet and outlet piping at each end of the cage.
Use hand valves to balance the liquid flow through the
cage and keep the displacer cage filled. It is advisable
to provide a rotameter or sight flow gauge for measuring velocity through the cage. If the flow rates are
properly balanced, the transmitter output will show
little change when flow through the cage is shut off. If
the flow rate through the cage is too high the turbulence may cause an erratic output pressure signal.
Readjust hand valves to stabilize the output pressure
signal.
Regulator Supply Pressure
WARNING
Do not overpressurize any system component. Personal injury or property
damage may occur due to sudden pressure release or explosion. To avoid
damage, provide suitable pressure-relieving or pressure limiting devices if
supply pressure can exceed the maximum supply pressure listed in table 1.
Personal injury or property danage may
occur from an uncontrolled process if
the supply medium is not clean, dry, oilfree, or non-corrosive gas. Industry instrument air quality standards describe
acceptable dirt, oil, and moisture content. Due to the variability in nature of
the problems these influences can have
on pneumatic equipment, Fisher Controls has no technical basis to recommend the level of filtration equipment
required to prevent performance degradation of pneumatic equipment. A filter
or filter regulator capable of removing
A1317-1/IL
Figure
10. Piezometer-Ring Cage for Flow Line Mounting
particles 40 microns in diameter will suffice for most applications. Use of suitable filtration equipment and the establishment of a maintenance cycle to
monitor its operation is recommended.
Standard 2502 Series controllers come complete with
supply and output pressure gauges and an integrally
mounted Type 67FR regulator to reduce supply pressure from a maximum of 250 psig (17.3 bar) to the 20
or 35 psig (1.4 or 2.4 bar) required. This regulator has
built-in relief and a standard 40-micron to remove particles from the supply source.
The output pressure connection is on the back of the
controller case (figure 3). Pipe the supply pressure to
the in connection of the regulator mounted to the case
back. Provide a clean, dry, and noncorrosive air or gas
supply to the controller as follows:
After pressure connections have been made, turn on
the supply pressure and check all connections for
leaks.
8
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29A2834-C
30A8943-H
A1933/IL
2502 Series
RESET ADJUSTMENT
W5637/IL/A
Prestartup Checks
WARNING
The following calibration procedure requires taking the controller out of service. To avoid personal injury and property damage caused by an uncontrolled
process, provide some temporary
means of control for the process before
taking the controller out of service.
21A6447-A
A1903/IL
Figure 11. Controller Adjustments
Adjustment locations are shown in figure 11 unless
otherwise indicted. When performing the checks, open
loop conditions must exist. One way to obtain an open
loop is to ensure that there is no flow through the final
control element. Another way to obtain an open loop is
to disconnect the controller output signal line and plug
the output connection.
During startup, it is necessary to change process levels to position the displacer from its maximum to its
minimum range of operations. Provide a means to
change the process level or interface. If the process
variable cannot be varied sufficiently, follow the in-
1E8731-C
1E8732-C
A1897-1/IL
9
Page 10
2502 Series
structions in the Calibration section to simulate the
process variable changes required for these checks.
Make sure that the raise level dial on the controller is
mounted with the correct side facing out. The dial is
printed on both sides with the arrow on one side pointing to the left and the arrow on the other side pointing
to the right. Figure 11 shows the dial arrow positioned
for a sensor that is mounted to the left of the controller; the arrow points to the left. If the sensor is to the
right of the controller, remove the two mounting
screws, turn the dial over so the arrow points to the
right, then reinstall the mounting screws.
On a controller with optical mechanical indicator assembly, the travel indicator plate is printed on both
sides. If the sensor is to the left of the controller (righthand mounting), use the side of the plate that has the
arrow pointing to the left. If displacer is to right of controller (left-hand mounting), use the side of the plate
that has the arrow pointing to the right.
1. Turn on the supply pressure and check that the
controller supply gauge reads 20 psig (1.4 bar) for a 3
to 15 psig (0.2 to 1.0 bar) output pressure range or 35
psig (2.4 bar) for a 6 to 30 psig (0.4 to 2.0 bar) output
pressure range. If the pressure is incorrect, loosen the
locknut of the filter/regulator (figure 3); turn the adjusting screw clockwise to increase or counterclockwise to
decrease pressure. Tighten the locknut after setting
the pressure.
2. Turn the reset control to .05 minutes per repeat.
3. Locate the process variable at its minimum value
(on level applications, for instance, lower the liquid
below the displacer). Zero the proportional band and
raise level controls. Output pressure on direct-acting
controllers should be greater than zero but less than 3
psig (0.2 bar) for the 3 to 15 psig (0.2 to 1.0 bar) range
or 6 psig (0.4 bar) for the 6 to 30 psig (0.4 to 2.0 bar)
range. For reverse-acting controllers, the output pressure should be greater than 15 psig (1.0 bar) and less
than 20 psig (1.4 bar) for the 3 to 15 psig (0.2 to 1.0
bar) range or greater than 30 psig (2.0 bar) and less
than 35 psig (3.4 bar) for the 6 to 30 psig (0.4 to 2.0
bar) range. On a controller with indicator assembly,
the pointer should be over the low point on the indicator plate; slight adjustment might be necessary by
loosening the bottom shaft nut (key 40, figure 16),
shifting the pointer, and retightening the nut.
4. Set the raise level control as desired. Determine
the dial setting by moving the nameplate slide until the
specific gravity on scale B is opposite the displacer
volume on scale A. Choose the percentage of displacer length, as measured from the displacer bottom, that
you desire the liquid or interface level to cover. Locate
this percentage on scale D, and read up from this percentage to find the raise level dial setting on scale C.
For example, with a liquid level application, a specific
gravity of one (water service), and a 90-cubic-inch (1.5
L) displacer, move the slide so that 1.0 on scale B is
over 90 on scale A. If it is desired to have water level
cover 50 per cent of the displacer length at the control
point, read up from 50 on scale D to find a 4.5 dial setting on scale C.
5. Relocate the process variable to the control point
determined in step 4. If not, see if another setting on
the raise level dial brings the output pressure into
agreement with the process. For example, with water
level at 50 percent of the height of the displacer, the
output of a 3-15 psig (0.2 to 1.0 bar) unit should be
aproximately 50 percent of the way between 3 and 15
psig (0.2 and 1.0 bar) or 9 psig (0.6 bar). If the new
setting is more than one graduation away from the
setting determined in step 4, the unit would appear to
be out of calibration and recalibration may be desirable. See Calibribration Procedure on page 12 steps 1
thru 10.
On a controller with level indicator, the pointer should
reflect the magnitude of the process variable; for
instance, with liquid or interface level covering 50 percent of the displacer, the pointer should be in the
middle of the high-low scale. Slight plate adjustment
might be necessary as described at the end of step 3.
6. If all prestartup checks are satisfactory proceed to
the Startup section.
Adjustments
Controller adjustments are provided in this section.
Refer to figure 11 for adjustment locations.
Level Set Adjustment
To perform the level adjustment, open the controller
cover, loosen the knurled adjustment screw (see figure
11), and rotate the adjustment lever around the RAISE
LEVEL dial. To raise the fluid or interface level, or increase density, rotate this knob in the direction of the
arrows. To lower the level or decrease density, rotate
the knob in the opposite direction. This procedure is
the same for both direct and reverse action controllers.
Tighten the knurled screw.
Note
The raise level dial does not reflect actual fluid level in the tank or fluid level
position on the displacer.
Proportional Band Adjustment
Proportional band adjustment is made to change the
amount of displacement force change required to obtain full output pressure change, by determining the
10
Page 11
2502 Series
percentage of pressure fed back to the proportional
bellows. The adjustment is performed by opening the
controller cover and turning the percent proportional
band knob (just below the raise level dial).
Reset Adjustment
To adjust reset action (figure 11) turn the knob clockwise to decrease the minutes per repeat. Turn the
knob counterclockwise to increase the minutes per
repeat. Increasing the minutes per repeat provides a
slower reset action.
The reset rate adjustment dial is calibrated in minutes
per repeat. By definition, this is the time in minutes
required for the reset action to produce a correction
which is equal to the correction produced by proportional control action. This is, in effect, the time in minutes required for the controller to increase (or decrease) its output pressure by an amount equal to a
proportional increase (or decrease) caused by a
change in control conditions.
Differential Relief Adjustment
The differential relief valve protrudes from the back of
the controller case on a construction with an F in the
type number. Although normally factory-set to relieve
when the differential between the proportional and reset bellows reaches 5 psi, the differential may be reduced down to 2 psi by turning the adjustment screw
clockwise or increased up to 7 psi by turning the screw
counterclockwise. The minimum differential setting will
yield the minimum set point overshoot during startup.
Depending on the characteristics of the process, the
relief valve can be positioned so that the arrow cast on
the case points either to the letters RE (reset) or to the
letter P (proportional) on the back of the manifold. To
reposition the arrow, see figure 11. Remove the
mounting screws. Reposition the differential relief
valve to RE or P and reinstall the mounting screws.
To calibrate a controller, it is necessary to place the
device into operation. This may be done on the vessel
with the actual service liquid. It may also be done in
the shop, but other means of obtaining a displacement
force change must be provided. It must be done in the
shop if the process variable is not available for calibration or if the process cannot be varied for calibration.
There are two methods of adapting the calibration procedure to shop calibration: wet and dry.
Wet Calibration
Remove the entire controller and sensor assembly
from the vessel. For caged sensors, pour the liquid
into the cage. For cageless sensors, suspend the displacer to an appropriate depth in a liquid having a specific gravity equal to that of the process liquid.
If necessary, use water for wet calibration in the shop.
However, this procedure requires compensation for
the difference between the specific gravity of the water
and that of the process liquids. For example, assume
that the process liquid has a specific gravity of 0.7 and
that wet calibration with water (specific gravity of 1.0)
is desired. To simulate a process level of 50 percent of
the input span, a water level of 35 percent is required
(0.7/1.0 x 50 percent = 35 percent).
Dry Calibration
Remove the controller and torque tube arm, as a
single unit, from the cage or vessel. Then, wherever
the standard calibration instructions in this manual require a specific process variable for input to the sensor, simulate that variable by suspending the proper
weight (such as a can of sand) from the end of the
displacer rod. Complete the following Controller and
Torque Tube Arm Disassembly and the Determining
Suspended Weight for Calibration sections before proceeding to the calibration procedure.
Controller and Torque Tube Arm
Disassembly
Calibration
Precalibration Requirements
Note
Calibration of a unit with a displacer designed for interface or density control
must be conducted with the displacer
completely submerged in a liquid of the
specific gravity for which the unit was
designed.
WARNING
To avoid personal injury from contact
with the process liquid, lower the vessel
level below the sensor torque tube arm,
or shut off the cage equalizing valves
and drain the cage before proceeding.
For closed vessels, release any pressure that may be in the vessel before
removing the sensor assembly.
When removing the displacer from the displacer rod or
removing the controller and torque tube arm from the
11
Page 12
2502 Series
cage or vessel, refer to the appropriate sensor instruction manual for assistance. The method of removing
the displacer or torque tube arm and attached controller will vary with the type of sensor.
For a caged sensor with top equalizing connection, it
may be appropriate to remove the entire cage from the
vessel before disassembling.
CAUTION
If the displacer is to be disconnected
from the displacer rod before the sensor
assembly is removed from the cage or
vessel, provide a means of supporting
the displacer to prevent it from dropping
and suffering damage. The spuds or
stem end pieces on all displacers have
holes suitable for inserting rods or other
supports.
Additionally, a threaded rod may be
installed into the 1/4-inch 28 UNF
threaded hole in the displacer spud or
stem end piece of top-mounted cageless
and all caged sensors. For some topmounted sensors with long displacers,
it may also be possible to remove the
sensor through the access hole in the
sensor head.
For Type 249BP sensor with the travel
stop, the stem end piece pins will secure the displacer as long as the travel
stop plate is installed and the sensor
head is in position.
Determining Suspended Weight for
Calibration
where:
Ws = Total suspended weight in pounds (should
never be less than 0.5 pounds). For a unit with
a horizontal displacer, make sure the center of
gravity of the substitute weight is where it
would be on the actual displacer.
Note
For liquid level control only, simulate
the lower range limit of the input span
by suspending the displacer from the
displacer rod. For other values of input
span, remove the displacer and suspend
the appropriate weight as determined in
the equation above.
Wd = Weight of the displacer, in pounds (determine
by weighing displacer).
0.0361 = Weight of one cubic inch of water (specific
gravity = 1.0), in pounds.
V = Volume of the displacer in cubic inches, that
would be submerged at the level required by
the calibration procedure. Or,
V = π/4 (displacer diameter)2 x (length of displacer
submerged)
SP GR = Specific gravity of the process liquid at
operating temperature.
For interface level measurement, the equation becomes:
Ws = Wd - [(0.0361) (V1) (SP GR1) +
(0.0361) (Vh) (SP GRh)]
where:
CAUTION
To avoid overloading a torque tube
sized for interface or density applications under dry conditions, consult your
Fisher Controls sales office or sales representative for the maximum allowable
substitute weight Ws that can be used
with your particular construction.
To determine the total weight that must be suspended
from the displacer rod to simulate a certain condition
of liquid level or specific gravity, solve the following
equation:
Ws = Wd - [(0.0361) (V) (SP GR)]
12
V1 = Volume of the displacer submerged by the
lighter liquid, in cubic inches.
Or,
V = π/4 (displacer diameter)2 x (length of the dis-
placer submerged)
SP GR1 = Specific gravity of the lighter liquid at op-
erating temperature.
Vh = Volume of the displacer submerged by the
heavier liquid, in cubic inches.
Or,
V = π/4 (displacer diameter)2 x (length of the dis-
placer submerged)
Page 13
2502 Series
Table 2. Minimum and Maximum Limits for Setting Process Variables
Application Minimum Limit Maximum Limit
Liquid level Displacer must be completely out of liquid Displacer must be completely submerged in liquid
Interface
Density
Displacer must be completely submerged in the upper
of two process liquids
Displacer must be completely submerged in liquid having
highest specific gravity expected
Displacer must be completely submerged in the lower
of two process liquids
Displacer must be completely submerged in liquid
having the lowest specific gravity expected
SP GRh = Specific gravity of the heavier liquid at
operating temperature.
Calibration Procedure
WARNING
The following calibration procedure requires taking the controller out of service. To avoid personal injury and property damage caused by an uncontrolled
process, provide some temporary
means of control for the process before
taking the controller out of service.
Figure 11 shows adjustment locations for the following
steps, except as otherwise indicated. When calibrating, open loop conditions must exist. One way to obtain an open loop is to place the final control element
into manual control or bypass it. If there is no provision
for manual control, shut down the process. It is recommended that a test pressure gauge be installed in the
controller output line for subsequent calibration steps.
Several steps in these calibration procedures require
setting the process variable at its minimum and maximum limits according to table 2. Reverse-acting controllers produce the opposite response.
1. Connect a supply pressure source to the controller
and provide a supply pressure suitable for the sensing
element range: 20 psig (1.4 bar) for a 3 to 15 psig (0.2
to 1.0 bar) output pressure range or 35 psig (2.4 bar)
for a 6 to 30 psig (0.4 to 2.0 bar) output pressure range.
2. Rotate the reset knob to 0.01 minutes per repeat.
3. Rotate the proportional band knob to zero.
4. Set the liquid at the minimum limit (dry displacer).
5. Turn the raise level knob to zero.
8. Turn the raise level knob until the out put pressure is
15 psig for a 3 to 15 psig signal range (1.0 bar for a 0.2
to 1.0 bar signal range) or 30 psig for a 6 to 30 psig signal range (2. 0 bar for a 0.4 to 2.0 bar signal range).
9. The controller is within its calibration accuracy if the
raise level knob is between the 9.0 and 10.0 positions.
10. If the controller is out of calibration, adjust the calibration adjuster as follows:
Note
Loosen the two calibration adjuster
screws (key 45, figure 16), and slide the
calibration adjuster (key 100, figure 16)
in the desired direction.
a. If output is below 15 psig for a 3 to 15 psig signal range (1.0 bar for a 0.2 to 1.0 bar signal range)
or 30 psig for a 6 to 30 psig signal range (2.0 bar
for a 0.4 to 2.0 bar signal range) , move the adjustor a small distance away from the pivot to in-
crease span. Then repeat steps 4 through 9.
b. If output is above 15 psig for a 3 to 15 psig signal range (1.0 bar for a 0.2 to 1.0 bar signal range)
or 30 psig for a 6 to 30 psig signal range (2.0 bar
for a 0.4 to 2.0 bar signal range), move the adjustor
a small distance toward the pivot to decrease
span. Then repeat steps 4 through 9.
Note
If the controller cannot be calibrated,
look for other problems as described in
the Troubleshooting section, such as a
nonperpendicular flapper-nozzle condition, leaky connections, or a binding
displacer rod. If none of these troubles is
apparent, th e di spl acer or to rqu e tu be is
probably sized for a different set of service conditions. Ensure that the displacer
is sized correctly for the application.
6. Adjust the nozzle until output pressure is between
0 and 3 psig for a 3 to 15 psig signal range (0 and 0.2
bar for a 0.2 to 1.0 bar signal range) or 0 and 6 psig
for a 6 to 30 psig signal range (0 and 0.4 bar for a 0.4
to 2.0 bar signal range).
7. Set the liquid at the maximum limit (covered displacer).
Startup
Adjustment locations are shown in figure 11.
1. Set the raise level control to the desired control
point as determined in prestartup checks step 4.
13
Page 14
2502 Series
2. Set the percent proportional band control to 200.
3. Set the reset control to .05 minutes per repeat.
4. Slowly open the downstream and upstream manual
control valves in the pipeline and close the manual
bypass valve if one is used.
5. With the controller set at the desired control point,
narrow the proportional band until a cycling condition
exists. Then broaden the proportional band slightly
until stable control is obtained.
6. Adjust the reset control to obtain the highest reset
setting without introducing cycling.
7. To ensure that the optimum proportional band and
reset settings have been obtained, momentarily create
a load upset. If cycling occurs, broaden the proportional band slightly and repeat the load upset until stability
is attained. In general, the narrowest proportional band
and the highest reset setting that will not produce cycling will provide the best control.
Principle of Operation
All 2502 Series controllers use the same basic pressure-balanced relay with a yoked double-diaphragm
assembly (figure 12). This relay is connected so that
supply pressure is fed to the inlet side of the relay
valve and to the fixed restriction. From this restriction,
the air pressure goes into the relay chamber on the
side of the large diaphragm, and to the nozzle. As long
as there is no pressure change on either diaphragm,
the relay valve remains in equilibrium with both the
inlet and exhaust ends closed.
Type 2502 Controller
As long as inflow and outflow of the vessel ar e equal,
the beam and flapper remain mot ionless and allow supply pressure to bleed through the nozzle as fast as it
enters the relay thr ough the fixed rest rict ion. A level or
density change either raises or lowers the displacer and
pivots the beam and flapper with respect to the nozzle.
An increase in level or density with direct action, or a
decrease with reverse action, moves the beam and
flapper closer to the nozzle and restricts the escape of
supply pressure. This builds up the loading differential
on the side of the large diaphragm and opens the relay
valve to supply pressure inflow.
On the other hand, a decrease in level or density with
direct action, or an increase with reverse action,
moves the beam and flapper away from the nozzle
and permits supply pressure to bleed through the
nozzle faster than it can enter through the fixed restriction. This builds up the loading differential on the side
of the small diaphragm, and opens the relay valve to
exhaust loading pressure.
The three-way proportional valve can be opened and
adjusted to allow some or all of the output pressure
change to feed back to the proportional bellows in order to change the proportional band of the controller.
This pushes the beam and flapper opposite the way it
is being pivoted by the torque tube shaft, counteracting the pressure change in the nozzle and again stabilizing the relay diaphragm pressure differential. The
relay valve shuts off and maintains a new output pressure according to the change in sensed displacer position.
The area ratio of the large diaphragm to the small diaphragm is 3 to 1. A 12 psig (0.8 bar) pressure change
on the small diaphragm need only be balanced by a 4
psig (0.3 bar) change on the large diaphragm.
A change in liquid level, interface level, or density
changes the buoyant force exerted on the sensor displacer, which in turn imparts a rotary motion through
the torque tube shaft. The rotary motion is applied to
the controller, which uses a nozzle, bellows, and pneumatic relay to convert the rotary motion to a standard
pneumatic output signal. The output signal is sent to a
final control element. In conjunction with this control
element, 2502-249 Series controller-sensors are capable of bringing the controlled variable back to a specific control point all the time.
The following descriptions show how the relay works
in conjunction with the standard proportional-plus-reset
controller, and how the reset relief valve construction
works.
14
A wide-open proportional valve permits feedback of all
the output change and produces 100 percent proportional response. Closing of this valve produces smaller
proportional responses, since part of the output
change is vented through the valve exhaust and only
the remainder is available to reposition the bellows.
The reset valve can be adjusted to channel some or all
of the proportional pressure into a reset bellows that
opposes proportional bellows action. This automatically dampens the effect of any proportional overcorrection by a set amount per time interval, as long as there
is a deviation from the control point.
Figure 12 illustrates these principles at work in a direct-acting right-hand-mounted construction controlling
liquid inflow to a vessel, by means of a direct-acting
diaphragm-actuated control valve. Nozzle positions
and bellows connections would be reversed for direct
action with left-hand mounting or reverse action with
right-hand mounting.
Page 15
2502 Series
CD2114-A
CJ4081-A
C0313-1
Figure
12. Direct-Acting Right-Hand-Mounted 2502-249 Series Controller
Type 2502F Controller with Reset Relief
Valve
This construction (figure 13) has a differential relief
valve used to prevent proportional pressure from ex-
ceeding reset pressure by more than a set value, a
feature useful for intermittent control applications. Proportional valve output registers in the outer chamber of
the relief valve as well as in the proportional bellows.
15
Page 16
2502 Series
CJ4081-A
CU7387-B
C0311-2
Figure
13. Type 2502F Controller with Reset Relief Valve
A sudden increase in the output pressure will cause a
rapid pressure increase in the proportional bellows and
in the outer relief valve chamber. If the outer chamber
pressure exceeds that in the inner relief valve chamber by the amount of the relief pressure setting, the
relief diaphragm will move off the orifice in the relief
valve, and the pressure in the outer chamber will bleed
into the reset system. This action provides quick relief
of excessive proportional pressure and reduces the
time required by the system to return to the control
point.
Maintenance
The 2502 Series controllers are used in combination
with 249 Series sensors. Due to the care Fisher Controls takes in meeting all manufacturing requirements
(heat treating, dimensional tolerances, etc.), use only
replacement parts manufactured or furnished by Fisher Controls.
WARNING
Personal injury or property damage due
to sudden release of pressure, contact
with hazardous liquid, fire, or explosion
can be caused by puncturing, heating,
or repairing a displacer that is retaining
process pressure or liquid. This danger
may not be readily apparent when disassembling the sensor or removing the
displacer. Before disassembling the
sensor or removing the displacer, observe the more specific warning provided in the sensor instruction manual.
Troubleshooting
When troubleshooting, open loop conditions must exist
unless otherwise stated. When monitoring the process
variable, use the most accurate level indicting device
readily available. The output signal measuring device
should have a corresponding accuracy.
16
Page 17
2502 Series
Table 3 lists some common operating faults, their
probable causes, and corrective action.
Removing Controller from Sensor
WARNING
To avoid injury in the following steps,
turn off the supply pressure and carefully release any pressure trapped in the
controller before breaking any pressure
connection. Provide a bypass for the
control device if continuous operation
is required during maintenance.
Refer to figure 16 for key number locations, unless
otherwise indicated.
1. Disconnect the supply and output pressure tubing
from the controller.
Changing Mounting Method
WARNING
To avoid injury from contact with the
process liquid, lower the vessel level
below the torque-tube arm before proceeding. For closed vessels, release any
pressure that may be above the liquid.
Also, be careful to avoid overloading a
thin-wall torque tube and/or overweight
displacer.
Refer to figure 16 for key number locations.
1. Remove the controller as described previously.
2. A controller is attached to the sensor in one or the
other of the mounting positions shown in figure 4.
Right hand mount is with the case to the right of the
displacer when looking at the front of the case. Left
hand mount is with the case to the left of the displacer.
For a 249 Series sensor, remove the torque tube arm
from the sensor or vessel and reinstall the torque tube
arm in the opposite position according to the appropriate instruction manual.
2. Loosen the hex nut (key 40) that secures the operating arm base or pointer assembly (key 68 or 51) to
the torque tube rotary shaft. Do not lose the two link
bearings (key 87, not shown).
CAUTION
If the hex nut has not been loosened according to step 2, attempting to remove
the controller from the sensor may bend
the rotary shaft or operating arm and
linkage. Be careful that the back of the
controller case or the heat insulator
does not drop down and bend the rotary
shaft or shaft extension.
3. Remove any insulating tape from the joint between
the controller case and the torque tube arm. Remove
he four cap screws (key 39, figure 14) that hold the
controller or heat insulator to the torque tube arm. Pull
the case straight out from the torque tube arm, easing
it over the shaft coupling (key 36, figure 14) if one is
installed.
4. If the controller has a heat insulator, remove the
button head cap screws (key 40). Remove four washers (key 53) and the insulator assembly (key 35).
3. Check the desired control action to determine if it is
also necessary to reverse the controller action. The
nozzle block and bellows tubing should be arranged in
the proper position as shown in figure 15.
4. Remove the raise level dial, turn it over, and install
it in the desired position. The arrow on it under the
word FLOAT should point toward the displacer. On a
controller with indicator assembly, remove two screws
(key 41, figure 16), turn the front plate (key 54, figure
16) to the side that will have the float arrow pointing
toward the displacer, and secure the plate with the
screws.
5. Install the controller according to the next section.
Installing Controller on Sensor
Note
If the installation is in a location that is
not readily accessible and shop calibration is required, remove the torque tube
arm from the cage or vessel before mating the controller to the sensor. Install
the controller on the torque tube arm in
the shop; then calibrate and return the
controller and torque tube arm assembly to the installation.
17
Page 18
2502 Series
Fault Possible Cause Check Correction
1. Process wanders or cycles
around setpoint.
2. Controller controlling off setpoint
or switching point.
3. Controller cannot attain full
output range.
4. Controller remains at full or zero
output pressure.
Table
3. Troubleshooting Chart for 2502 Series Controllers
1.1 Proportional band or specific
gravity adjsutment incorrect or
improperly tuned control loop.
1.2 Supply pressure varying or
incorrect supply pressure setting.
1.3 Sensor not plumb and is in
contact with sidewall or leak in
displacer.
1.4 Relay malfunction. 1.4 Check for relay malfunction by
2.1 Supply pressure not set
correctly.
2.2 Leak in the controller loop. 2.2 Use soap and water to check
2.3 Leaking displacer. 2.3 Insure the displacer is not filling
2.4 Flapper adjustment. 2.4 Insure the flapper is not loose
2.5 Process variable changed. 2.5 Insure the process variable has
3.1 Supply pressure not set
correctly.
3.2 Flapper adjustment. 3.2 Insure the flapper is not loose
3.3 Process variable changed. 3.3 Insure the process variable has
3.4 Relay malfunction. 3.4 Check for relay malfunction by
3.5 Leaking controller loop. 3.5 Use soap and water to check
4.1 Supply or output pressure
gauge malfunction
4.2 Flapper adjustment. 4.2 Insure the flapper is not loose
1.1 Insure the prestartup
procedures are completed
correctly. Tune control loop.
1.2 Use input pressure gauge to
monitor stability. Make sure
regulator IN supply pressure is
withlin limits.
1.3 Check cage vessel and stillwell
installation, or for leaking displacer.
using the testing relay deadband
procedure
2.1 Make sure regulator supply
pressure is set correctly. Make sure
regulator IN supply pressure is
within limits.
for internal and external leaks.
with process fluid.
on the torque tube shaft and is
centered on the nozzle.
not changed from original
calibration settings or, displacer not
design specific gravity of process.
3.1 Make sure supply pressure is
set correctly. Make sure regulator
IN supply pressure is within limits.
on the torque tube shaft and is
centered on the nozzle.
not changed from original
calibration settings or, from
displacer design specific gravity.
using the testing relay deadband
procedure.
for internal and external leaks.
4.1 Insure the pressure gauges are
registering correctly.
on the torque tube shaft. Insure the
flapper is centered on the nozzle.
1.1 If stable control cannot be
attained and all other elements are
functionally correct, examine other
ossible causes related to the
controller/transmitter.
1.2 Apply correct supply pressure.
It is recommended to use one
regulator per instrument.
1.3 Make sure the displacer and
displacer rod hangs freely. Make
sure linkage is tight. Replace
displacer if leaking.
1.4 Depress plunger to clean out
the fixed restriction. Replace or
repair relay using the procedure in
the Maintenance section.
2.1 Reset the supply regulator
pressure. If the condition occurs
again, rebuilld or replace regulator.
Provide a regulator input pressure
within regulator limits.
2.2 Replace or repair leaking parts
as necessary.
2.3 Refer to sensor maintenance
procedures in the appropriate
sensor instruction manual.
2.4 Replace or tighten flapper
assembly as necessary and/or
center flapper on nozzle.
2.5 Change process variable back
to original sepcification or
recalibrate. If necessary, provide
replacement displacer of correct
size and recalibrate.
3.1 Reset the regulator pressure. If
problem reoccurs, replace or
rebuild the regulator. Insure
regulator IN supply pressure is
within limits at all operating levels.
3.2 Replace or tighten flapper
assembly as necessary and/or
center flapper on nozzle.
3.3 Change process variable back
to original specificaton or
recalibrate. If necessary, provide
replacement displacer of correct
size and recalibrate.
3.4 Depress plunger to clean out
the fixed restriction. Replace or
repair relay using the procedure in
the Maintenance section.
3.5 Replace or repair leaking parts
as necessary.
4.1 Replace pressure gauges. Use
corrective action given in section 3
of this table.
4.2 Replace or tighten flapper
assembly as necesary and/or
center flapper on nozzle.
Perform step 1 only if adding a heat insulator to a
unit that does not have one. Key numbers in this
step are shown in figure 14.
18
1. To install the heat insulator, secure the shaft extension (key 37) to the torque tube assembly rotary shaft
with the shaft coupling (key 36). Tighten both set
screws (key 38), with the coupling centered as shown
Page 19
2502 Series
20A7423-C/DOC
Figure
14. Heat Insulator Shown Installed on 249 Series
in the figure. Then mount the insulator assembly (key
35) on the controller case with four washers (key 53)
and button-head cap screws (key 40). Tighten the
screws.
CAUTION
In the following step, avoid bending the
torque tube rotary shaft of the torque
tube assembly. Bending or side loading
of this shaft could cause erroneous
readings. Additionally, make sure the
ball bearing assembly (key 12, figure 16)
is removed from the case (key 1, figure
16) to provide clearance when installing
the case on the sensor.
2. Remove the bearing assembly (key 12) from the
case (key 1).
3. Carefully slide the controller case straight in, guiding the bearing assembly (key 12), operating arm base
or pointer assembly (key 68 or 51, figure 16) over the
rotary shaft and easing an attached heat insulator over
the shaft coupling (key 36, figure 14) if necessary. Secure the case or insulator to the torque tube arm with
the four cap screws (key 39, figure 14).
AV2323-A
AV2322-A
B0995-2/IL
Figure
15. Nozzle, Flapper, and Tubing Arrangements
for Various Actions and Mountings
Note
If a heat insulator is used, do not insulate its exterior.
4. On a unit without a heat insulator, tape the joint
between the case and torque tube arm to minimize the
entrance of atmospheric moisture around the torque
tube rotary shaft.
19
Page 20
2502 Series
5. Install and tighten the bearing assembly (key 12) in
the case (key1). Secure the operating arm base or pointer assembly to the rotary shaft by tightening the hex nut
(key 40, figure 16). Connect the supply and output pr essure tubing and perform the calibrat ion procedure.
Changing Proportional, Reset, or
Differential Relief Valve
1. Remove the proportional band valve assembly (key
36, figure 16) by unscrewing it from the relay base
(key 23, figure 16). Install the desired replacement
assembly, or a 1/8-inch (3.2 mm) NPT pipe plug into
the proportional band tapping if testing relay dead
band.
2. To change the reset restrict ion valve assembly (key
91), remove the two mounting screws (key 182) located
on the back side of case. Install the replacement valve
assembly, and reconnect the tubing connections.
3. Remove the differential relief valve assembly (key
186, figure 16) by removing the two mounting screws
(figure 11) that anchor the valve to the manifold (key
184, figure 16). Install the valve with the arrow pointing
to the same letter(s) as before removal, unless it is
desired to change the relief action.
Testing Relay Dead Band
1. Replace the proportional band adjustment assembly with a 1/8-inch (3.2 mm) NPT pipe plug according
to the Changing Proportional, Reset, or Differential
Relief Valve section.
2. Turn on the supply pressure and set it to 20 or 35
psig (1.4 or 2.4 bar).
3. By changing the process variable and adjusting the
raise level control, set the output pressure to 15 or 30
psig (1.0 or 2.0 bar). While monitoring the output pressure, slowly change the process until an output pressure change can just be detected, and record the value of the process variable at the detection point.
4. Change the process variable in the opposite direction until another output pressure change can be detected, and again record the value of the process variable. If the difference between the two recorded
values (the dead band) is more than 0.2 percent of the
maximum displacer length, the relay will have to be
replaced or repaired according to the Changing Relay
and the Disassembling Relay sections.
5. Turn off the supply pressure, remove the pipe plug,
and install the proportional band adjustment assembly.
Changing Relay
The relay may be removed for cleaning or repair, and
must be taken off to remove the lower bellows.
1. On a controller with indicator assembly, loosen the
two lower screws (key 96, figure 17) of the relay case
and slide out the indicator base plate (key 53, figure 16).
2. Disconnect the tubing (key 11, figure 16) from the
relay.
3. Remove both mounting screws, the relay, and the
relay gasket (keys 43, 34, and 22, figure 16).
4. Install a new gasket, the replacement relay if necessary, and both mounting screws. Reconnect the tubing. On a controller with indicator assembly, slide the
base plate under the two lower screws of the relay
case, align the plate so that the pointer will read properly, and tighten the screws.
Replacing Bellows
Key numbers are shown in figure 16.
1. To gain access to the lower bellows, remove the
relay according to the Changing Relay section.
2. Remove the upper and lower bellows frame screws
(key 96) that hold both bellows assemblies to the bellows frame. Unscrew each bellows from the spacer
(key 98), being careful not to lose the O-ring (key 57,
not shown) from the spacer end of the bellows.
3. Inspect each bellows and O-ring and replace if necessary, using an unpainted bellows for a 3 to 15 psig
(0.2 to 1.0 bar) range and a red bellows for a 6 to 30
psig (0.4 to 2.0 bar) range. Be sure to install the O-ring
at the spacer end of the bellows.
4. Install each bellows by screwing it down over the
stud (key 97, not shown) protruding from each end of
the spacer. Secure with a bellows frame screw, and
install the relay according to the Changing Relay section if it was removed.
5. Perform the calibration procedure and any other
necessary part of the calibration sequence.
Reversing Action
Note
The following procedure will be necessary to restore previous action if the
mounting method has been changed.
Key numbers are shown in figure 16.
1. Remove two screws (keys 63 and 64), two seal
rings (key 55), and the nozzle block (key 101). Check
seal ring condition and replace rings as necessary.
2. Install the nozzle block, seal rings, and screws on
the opposite side of the beam as shown in figure 15.
Disconnect the proportional band tubing (key 76) and
one of the two pieces of reset tubing (key 75) from the
bellows frame (key 94) and reconnect them in the
proper orientation as shown in figure 15.
20
Page 21
2502 Series
Note
Beam overtravel can jam the flapper
against the nozzle if the following step
is not performed.
3. Remove the flapper screw (key 93), lockwasher
(key 84), and flapper (key 60). Invert the flapper so
that the flapper hook is on the opposite side of the
beam from the nozzle (key 58), and secure with the
lockwasher and screw.
4. Perform the calibration procedure and any other
necessary part of the calibration sequence.
Disassembling Relay
Disassembly can be accomplished in the following
steps. Key numbers are shown in figure 17.
1. Remove the relay according to the Changing Relay
section.
2. Remove the orifice assembly (key 88) and check
for orifice plugging or damage. Replace the O-ring
(key 90) before installing the orifice assembly.
3. Remove the casing screws (key 96) and washers
(key 98), casing assembly (key 85), and top diaphragm (key 91). On a high-temperature relay also
remove the top gasket (key 100) that covers the top
diaphragm.
4. Remove the spacer ring (key 84), diaphragm assembly (key 86), and relay spring (key 92) from the
relay body (key 83). On a high-temperature relay also
remove the bottom gasket (key 99) from underneath
the diaphragm assembly.
5. Remove the screws (key 97), spring plate (key 95),
spring plate gasket (key 94), spring (key 93), and
valve plug (key 87).
6. Inspect the diaphragms and gaskets and replace if
necessary. Also replace the spring and valve plug if
they show signs of corrosion. The lower diaphragm
comes as part of an assembly and must be installed
as such. Clean all parts thoroughly before assembling.
7. Put the valve plug and its spring in the relay body.
Replace the spring plate gasket and spring plate and
secure with four screws.
8. Place the relay spring in the relay body and, on a
high-temperature relay, install a bottom gasket. Install
the diaphragm assembly, spacer ring, and top diaphragm on the body so that all flow passage holes are
lined up. On a high-temperature relay also install a
gasket over the top diaphragm.
9. Put the casing assembly on the top diaphragm so
that the lugs on the casing and spacer ring line up and
are also lined up with the body lug.
10. Install the casing screws and tighten them slowly
to ensure a good seal.
11. Install the assembled orifice assembly, and install
the relay according to the Changing Relay section.
Parts Ordering
Whenever corresponding with the Fisher Controls
sales office or sales representative about this equipment, always mention the controller type number and
the serial number found on the unit nameplate (figure
11). When ordering replacement parts, also state the
complete 11-character part number of each required
part as found in the following parts list.
Parts Kits
Key Description Part Number
Controller Parts Kit
Contains keys 12, 15, 21, 24, 38, 55, 57, 58, 60, 62, 63, 64,
77, 79, 84, 86, 87, 93, 101, and 187
Standard Temperature
High Temperature
Relay Parts Kit
Contains keys 22, 85, 86, 87, 88, 90, 91, 92, 93 and 94,
(99 and 100 high temp only)
Standard Temperature RRELAY X0L12
High Temperature
Relay Replacement Kit
Contains keys 22, 43, and the relay assembly
Standard Temperature RRELAY X0L22
High Temperature
Heat Insulator Parts Kit
Contains keys 35, 36, 37, 38, 39, 40, and 53
Parts
List
Heat Insulator (figure 14)
35 Heat Insulator Assembly, stainless steel 22A0033 X012
36 Shaft Coupling, stainless steel
37 Shaft Extension, K-Monel
38 Set Screw, stainless steel (2 req’d) 1E6234 X0022
39 Cap Screw, steel, pl (4 req’d)
40 Cap Screw, steel, pl (4 req’d)
53 Washer, carbon steel, pl (4 req’d)
Controller Common Parts (figure 16)
1 Pilot Case Back, zinc
Types 2502 and 2502C
Type 2502F 23A2073 X012
2 Pilot Case Cover, aluminum 50B9454 X012
3 Door Handle, steel, pl
4 Door Handle Shaft (not shown),
stainless steel
5 Machine Screw, stainless steel
6 Washer Spring, stainless steel
7 Door Hook, steel, pl
8 Elastic Stop Nut, steel, pl
9 Drive Pin, (2 req’d)
11 Relay Tubing
Copper 17A9100 X012
Stainless steel (2502 and 2502C only) 17A9100 X022
12* Ball Bearing Ass’y, brass, pl
R2502 X0L52
R2502 X0H52
RRELAY X0H12
RRELAY X0H22
R2500XH 0012
1A5779 35032
1B6815 40022
1A3816 24052
1V2395 28982
1B8659 28982
1J4157 44012
1C8972 25082
1C8984 14012
1C8958 X0022
1C8970 36032
1C8971 25082
1C8959 X0012
1C8991 X0022
1C8983 000A2
*Recommended spare part.
21
Page 22
2502 Series
30A8942-H/DOC
43A2366-H/DOC
30A8943-H/DOC
22
Figure 16. 2502 Series Controller Constructions
Page 23
2502 Series
Key Description Part Number
13 Retaining Ring, steel, pl (zinc case
cover only) (2 req’d)
14* Gauge Glass, glass, (2 req’d)
15* Gauge Glass Gasket, neoprene, (2 req’d)
18 Instruction Label, aluminum 29A2834 X012
19* Pressure Gauge (2 req’d)
Brass, triple scale
0-30 psig/0-0.2MPa/0-2.0 bar 11B8577 X012
0-60 psig/0-0.4MPa/0-4.0 bar 11B8577 X022
Stainless steel, triple scale
0-30 psig/0-0.2MPa/0-2.0 bar 11B8583 X012
0-60 psig/0-0.4MPa/0-4.0 bar 11B8583 X022
21* Cover Gasket, nitrile
22* Relay Gasket
Standard, neoprene
High-temperature, rubber
23 Relay Base, aluminum 47A0950 X012
24* Relay Base Gasket (not shown)
Standard, neoprene
High-temperature, rubber
29 Drive-lok Pin, stainless steel
31 Shaft Clamp Screw, stainless steel
34 Pilot Relay (parts shown under separate heading)
Standard 22B0463 X012
High-temperature 22B0462 X012
35 Level Adjustment Ass’y 10A8939 X0A2
36 Proportional Valve Ass’y 10A9122 X042
38* Filter Gasket (not shown)
Standard, neoprene
High-temperature, rubber
39 Cap Screw (not shown), steel, pl (2 req’d)
40 Hex Nut, stainless steel
41 Screw, steel, pl (4 req’d for Type
2502C and FC, 2 req’d for all others)
42 Machine Screw, stainless steel, (8 req’d) 1V7435 X0022
43 Machine Screw, stainless steel (2 req’d) 1A3776 X0012
44 Machine Screw, steel, pl (4 req’d) 1A5733 X0012
45 Machine Screw, stainless steel (2 req’d)
47 Spring (not shown), stainless steel
49 Machine Screw, stainless steel (13 req’d) 1B7839 X0012
50 Screen, stainless steel
51 Pointer Ass’y (Type 2502C and FC only),
stainless steel/brass, pl
53 Base Plate, aluminum
(Type 2502C and FC only)
54 Front Plate, aluminum
(Type 2502C and FC only)
55*
O-Ring, (3 req’d)
Standard, nitrile
High-temperature, fluoroelastomer
57* O-Ring (not shown)
Standard, nitrile
High-temperature, fluoroelastomer
58* Nozzle, stainless steel
59 Beam, steel, pl
60 Flapper, Invar
61 Flapper Base, stainless steel
62* Connecting Link, Monel
63 Sealing Screw, stainless steel 14A5721 X012
64 Screw, stainless steel 24A5720 X012
65* Bellows Ass’y, brass (2 req’d)
3 to 15 psig (0.2 to 1.0 bar) 14A5726 X012
6 to 30 psig (0.4 to 2.0 bar) 14A5726 X032
66 Level Set Arm, steel, pl
67 Operating Arm, steel, pl
68 Operating Arm Base, brass, pl
Types 2502 and 2502F only)
(1)
36
1A4658 28992
0T0192 06042
0T0191 04082
1C9198 06432
1C8974 03012
1N8738 04142
1C8973 03012
1N8739 04142
1C8989 X0012
1B4514 35172
1C8986 03012
1N8740 04142
1C3988 X0022
1L2863 38992
1C9419 X0012
1H2675 X0012
1J4234 37022
0L0783 43062
1R2425 X0012
1E8731 11992
1E8732 11992
1D6875 06992
1N4304 06382
1E2226 06992
1N8387 06382
1U6391 35132
1K8738 25072
1J4162 41132
1J4163 35032
1L3796 41012
1J4164 25072
1J4165 25072
1J4166 14022
Key Description Part Number
69 Level Set Pivot Pin, stainless steel
70 Pivot Base, steel, pl 19A9689 X012
71 Spring Washer, stainless steel
72 Washer, stainless steel
Types 2502 and 2502FC, (2 req’d) 1E8730 X0012
Type 2502C (4 req’d) 1E8730 X0012
74 Washer, stainless steel, (6 req’d)
75 Reset Tubing Ass’y (2 req’d),
copper 1J4169 000A2
stainless steel (2502 and 2502C only) 19A1887 X012
76 Proportional Band Tubing Ass’y
copper 1J4170 000A2
stainless steel (2502 and 2502C only) 1J4170 X0012
77* Bellows Frame Gasket (not shown)
Standard, neoprene
High-temperature, rubber
78 Spacer (not shown), brass
79* Bellows Gasket (2 req’d)
Standard, neoprene
High-temperature, rubber
80 Machine Screw, stainless steel, (4 req’d)
81 Machine Screw (not shown)
stainless steel, (2 req’d) 1P4373 X0012
82 Machine Screw, stainless steel, (4 req’d) 1B2752 X0022
83 Lock Washer, stainless steel (2 req’d)
84 Lock Washer, stainless steel
85 Cap Screw, stainless steel, not shown (4 req’d) 1A3816 K0012
86 Machine Screw, stainless steel (2 req’d) 1A8664 X00A2
87* Link Bearing (not shown)
stainless steel (2 req’d)
88 Machine Screw (not shown),
stainless steel, (4 req’d) 1J4159 X0012
89 Machine Screw, stainless steel, (2 req’d)
91 RESET Restriction Valve Ass’y
Types 2502 and 2502C
Standard 19A4357 X012
High-temperature 19A4357 X022
Type 2502F and 2502FC
Standard 19A4359 X012
High-temperature 19A4359 X032
93 Machine Screw, stainless steel 1B8776 X0012
94 Bellows Frame, aluminum
95 Bellows Frame Base (not shown), steel, pl
96 Bellows Screw, brass, pl (2 req’d)
97 Bellows Stud (not shown), brass
98 Spacer, zinc
99 Cross Spring, stainless steel (2 req’d)
100 Calibration Adjuster, zinc
101 Reversing Block, zinc 26A0975 X012
180 Pipe Nipple (not shown) Type 2502F
and 2502FC only), steel
181 Relief Tubing Ass’y (Type 2502F and
2502FC only), copper 13A2077 X012
182 Machine Screw, stainless steel, (2 req’d)
Types 2502 and 2502C (not shown) 1B7839 X0012
Type 2502F and 2502FC
183* O-Ring (2 req’d), Type 2502F and 2502FC only
Standard, nitrile
High temperature, fluoroelastomer
184 Manifold, aluminum, (Type 2502F and
2502FC only) 23A2072 X012
185 Manifold Nipple, aluminum (Type 2502F only) 13A2074 X012
186 Differential Relief Valve Ass’y (Type 2502F and 2502FC only)
Standard 21A6447 X0A2
High temperature 21A6447 X012
187 Sleeve, plastic 16A0976 X012
1J4167 35162
1H8851 X0012
6100057 0X12
1H2654 03012
1N8735 04142
1J6198 15122
1D3970 03012
1N8736 04142
1H2678 X0012
6100081 0X12
1C3162 X0012
1L3795 46202
1H8162 X0012
2H2653 08012
1J4160 25142
1D3976 14022
1H2658 14012
1H2659 44012
1H2660 37032
2H2662 44012
1C5599 26232
1C8969 X0012
1D6875 06992
1N4304 06382
*Recommended spare part.
1. Invar is a mark owned by Carpenter Technology Corp.
23
Page 24
2502 Series
22B0463-A/DOC
22B0462-A/DOC
Figure 17. Relay Constructions
Key Description Part Number
188* 0-Ring (Type 2502F and 2502FC only),
Standard
High temperature
215 Nameplate, metal 12B6337 X0A2
1C8538 06992
1C8538 X0052
Relay (figure 17)
83 Relay Body, aluminum/brass 48A3776 X012
84 Spacer Ring, aluminum 38A3778 X012
85 Casing Ass’y, aluminum/steel 12B0460 X012
86* Diaphragm Ass’y
Standard, nitrile/nylon 18A2451 X012
High-temperature, polyacrylate/nylon 18A2451 X092
87* Valve Plug, brass
88* Orifice and Core Ass’y, brass 12B0468 X012
90* O-Ring, nitrile, (2 req’d)
Standard
High temperature
Level-Trol, Fisher, Fisher-Rosemount, and Managing The Process Better are marks owned by Fisher Controls International, Inc. or Fisher-Rosemount Systems, Inc.
All other marks are the property of their respective owners.
EFisher Controls International, Inc. 1977, 1994; All Rights Reserved
For information, contact Fisher Controls:
Marshalltown, Iowa 50158 USA
Cernay 68700 France
Sao Paulo 05424 Brazil
Singapore 128461
24
Printed in U.S.A.
0Y0617 14012
1D6875 06992
1N4304 06382
Key Description Part Number
91*
Top Diaphragm
Standard, nitrile
High-temperature, polyacrylate 1K6999 X0012
92 Relay spring, steel, pl
93 Valve Spring, stainless steel
94* Spring Plate Gasket
Standard, neoprene
High-temperature, rubber
95 Spring Plate, steel, pl
96 Machine Screw, stainless steel, (6 req’d) 1A3294 X0022
97 Machine Screw, stainless steel
98 Washer (standard only), stainless steel (6 req’d) 1P8261 X0012
99* Bottom Gasket (high-temperature only), rubber
100* Top Gasket (high-temperature only), rubber
*Recommended spare part.
(4 req’d)
1L5556 02042
1C8961 27012
0X0836 37022
1H2696 03012
1K7000 04142
1H2697 25072
1A8664 X00A2
1K7001 04142
1K7002 04142
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