Fisher 2502 Series Level-Trol Instruction Manual
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
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
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
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.
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
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
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
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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