Rosemount™ 2120 Level Switch
Vibrating Fork
Reference Manual
00809-0100-4030, Rev GA
March 2022
Safety messages
NOTICE
Read this manual before working with the product. For personal and system safety, and for optimum product performance,
ensure you thoroughly understand the contents before installing, using, or maintaining this product.
For technical assistance, contacts are listed below:
Customer Central
Technical support, quoting, and order-related questions.
• United States - 1-800-999-9307 (7:00 am to 7:00 pm CST)
• Asia Pacific- 65 777 8211
North American Response Center
Equipment service needs.
• 1-800-654-7768 (24 hours a day — includes Canada)
• Outside of these areas, contact your local Emerson representative.
WARNING
Failure to follow safe installation and servicing guidelines could result in death or serious injury.
Ensure the level switch is installed by qualified personnel and in accordance with applicable code of practice.
Use the level switch only as specified in this manual. Failure to do so may impair the protection provided by the level switch.
The weight of a level switch with a heavy flange and extended fork length may exceed 37 lb. (18 kg). A risk assessment is required
before carrying, lifting, and installing the level switch.
WARNING
Explosions could result in death or serious injury.
Verify the operating atmosphere of the level switch is consistent with the appropriate hazardous locations certifications.
Before connecting a handheld communicator in an explosive atmosphere, ensure the instruments are installed in accordance with
intrinsically safe or non-incendive field wiring practices.
In explosion-proof/flameproof and non-incendive installations, do not remove the housing cover when power is applied to the
level switch.
The housing cover must be fully engaged to meet flameproof/explosion-proof requirements.
WARNING
Electrical shock could cause death or serious injury.
Avoid contact with the leads and terminals. High voltage that may be present on leads can cause electrical shock.
Ensure the power to the level switch is off, and the lines to any other external power source are disconnected or not powered while
wiring the level switch.
Ensure the wiring is suitable for the electrical current and the insulation is suitable for the voltage, temperature, and environment.
WARNING
Process leaks could result in death or serious injury.
Ensure the level switch is handled carefully. If the process seal is damaged, gas might escape from the vessel (tank) or pipe.
2
WARNING
Any substitution of non-recognized parts may jeopardize safety. Repair (e.g. substitution of components) may also
jeopardize safety and is not allowed under any circumstances.
Unauthorized changes to the product are strictly prohibited as they may unintentionally and unpredictably alter performance and
jeopardize safety. Unauthorized changes that interfere with the integrity of the welds or flanges, such as making additional
perforations, compromise product integrity and safety. Equipment ratings and certifications are no longer valid on any products
that have been damaged or modified without the prior written permission of Emerson. Any continued use of product that has
been damaged or modified without the written authorization is at the customer’s sole risk and expense.
WARNING
Physical access
Unauthorized personnel may potentially cause significant damage to and/or misconfiguration of end users’ equipment. This could
be intentional or unintentional and needs to be protected against.
Physical security is an important part of any security program and fundamental to protecting your system. Restrict physical access
by unauthorized personnel to protect end users’ assets. This is true for all systems used within the facility.
CAUTION
The products described in this document are NOT designed for nuclear-qualified applications.
Using non-nuclear qualified products in applications that require nuclear-qualified hardware or products may cause inaccurate
readings.
For information on Rosemount nuclear-qualified products, contact your local Emerson Sales Representative.
CAUTION
Hot surfaces
The flange and process seal may be hot at high process temperatures. Allow to cool before servicing.
3
4
Reference Manual Contents
00809-0100-4030 March 2022
Contents
Chapter 1 Introduction.............................................................................................................. 7
1.1 Using this manual........................................................................................................................ 7
1.2 Product certifications...................................................................................................................7
1.3 Product recycling/disposal...........................................................................................................7
Chapter 2 Level switch overview................................................................................................ 9
2.1 Measurement principles.............................................................................................................. 9
2.2 Process characteristics.................................................................................................................9
2.3 Vessel characteristics...................................................................................................................9
2.4 Application examples.................................................................................................................10
2.5 Components of the level switch.................................................................................................12
Chapter 3 Mechanical installation............................................................................................ 15
3.1 Safety messages........................................................................................................................ 15
3.2 Installation considerations.........................................................................................................16
3.3 Installation procedures.............................................................................................................. 26
Chapter 4 Electrical installation................................................................................................33
4.1 Safety messages........................................................................................................................ 33
4.2 Prepare the electrical connections............................................................................................. 34
4.3 Connect wiring and power up.................................................................................................... 48
Chapter 5 Operation................................................................................................................ 53
5.1 Output mode and time delay.....................................................................................................53
5.2 LED indication status..................................................................................................................54
Chapter 6 Service and troubleshooting.................................................................................... 55
6.1 Safety messages........................................................................................................................ 55
6.2 Magnetic test point....................................................................................................................56
6.3 Visual inspection........................................................................................................................58
6.4 Maintenance..............................................................................................................................58
6.5 Troubleshooting........................................................................................................................59
6.6 Spare parts................................................................................................................................ 60
6.7 Replacement and calibration of cassettes.................................................................................. 61
6.8 Opening the lid (cover).............................................................................................................. 63
6.9 Service support..........................................................................................................................63
Appendix A Specifications and reference data............................................................................. 65
A.1 General......................................................................................................................................65
A.2 Physical specifications............................................................................................................... 65
A.3 Performance specifications........................................................................................................67
A.4 Electrical specifications..............................................................................................................67
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A.5 Functional specifications........................................................................................................... 68
A.6 Environmental specifications.....................................................................................................68
A.7 Dimensional drawings............................................................................................................... 71
6 Reference Manual
Reference Manual Introduction
00809-0100-4030 March 2022
1 Introduction
1.1 Using this manual
The sections in this manual provide detailed information on installing, operating, and
maintaining the Rosemount 2120 Level Switch - Vibrating Fork.
The sections are organized as follows:
Level switch overview provides a description of the level switch and its basic principles.
Mechanical installation contains mechanical installation instructions.
Electrical installation contains electrical installation instructions.
Operation contains how to adjust the operation and what the LED indications mean.
Service and troubleshooting provides troubleshooting techniques for the most common
operating problems.
Specifications and reference data supplies reference and specification data.
1.2 Product certifications
See the Rosemount 2120 Product Certifications document for detailed information on the
existing approvals and certifications.
1.3 Product recycling/disposal
Recycling of equipment and packaging should be taken into consideration and disposed of
in accordance with local and national legislation or regulations.
Related information
Service support
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2 Level switch overview
2.1 Measurement principles
Using the principle of a tuning fork, a piezo-electric crystal oscillates the forks at their
natural frequency. Changes to the oscillation frequency are continuously monitored by
electronics as it varies depending on the liquid medium in which the forks are immersed.
The denser the liquid, the lower the oscillation frequency.
When used as a low-level point alarm, the liquid medium in the vessel (tank) or pipe drains
down past the fork, causing a change of oscillation frequency that is detected by the
electronics and switches the output state i.e. wet-to-dry.
When the level switch is used as a high-level point alarm, the liquid rises in the vessel
(tank) or pipe making contact with the fork and causing the output state to switch i.e. dryto-wet.
2.2 Process characteristics
Emerson's vibrating fork technology is virtually unaffected by turbulence, foam, solids
content, coating products, and liquid properties. The natural frequency (1400 Hz) of the
fork avoids interference from plant vibration that may cause false switching to a wet state.
This allows for minimum intrusion into the tank or pipe using a short fork.
2.3 Vessel characteristics
The level switch should be mounted using its process connection, and in a horizontal or
vertical orientation so that the liquid medium can flow freely in the gap between the forks.
A vessel (tank) or pipe can be almost any shape or type, but check that the process
conditions are within the operating limits of the level switch.
Avoid installing near agitators and inlet pipes where the forks are likely to be splashed and
cause a false switch to a wet state. False switching events can be minimized by an
adjustable time delay on the electronics cassette and allows time for the fork to dry.
Never force the level switch into a vessel (tank) or pipe space. Any contact with the
opposite wall, or in-tank objects, could damage the forks and other wetted-process parts.
Extended length versions require supports at regular spaced intervals.
Related information
Required supports for extended fork
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2.4 Application examples
Overfill prevention
Spillage caused by overfilling can be hazardous to people and the environment, resulting
in lost product and potentially high clean-up costs. The Rosemount 2120 is an overfill
prevention product from Emerson that can be used as one of multiple layers of protection.
It has been third party assessed and certified to IEC 61508.
High and low level point alarm
Maximum and minimum level detection in tanks containing different types of liquids are
ideal applications. It is common practice to have an independent high level alarm switch as
a backup to an installed level device in case of primary failure.
Pump control or limit detection
Batch processing tanks often contain stirrers and agitators to ensure mixing and product
‘fluidity’. The Rosemount 2120 has a user-selectable time delay, from 0.3 to 30 seconds,
that virtually eliminates the risk of false switching from splashing.
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Pump protection or empty pipe detection
With the fork projecting only 2 in. (50 mm) (dependent on connection type), the
Rosemount 2120 can be installed in small diameter pipes. Short forks mean minimum
intrusion on the wetside and allow for simple, low cost installation at any angle into pipes
or tanks. By selecting the option of direct load switching or relay electronics, the
Rosemount 2120 is ideal for reliable pump control and can be used to protect against
pumps running dry.
Wireless applications
The advent of wireless communications allows process plant managers to save up to 90%
on installation cost compared with wired technologies. More data can be collected at
central locations than has ever been possible before. The Rosemount 2120 can be used
with a Rosemount 702 Wireless Discrete Transmitter to enable these benefits for your
applications.
Hygienic applications
With the highly polished forks option providing a surface finish (Ra) better than 0.4 μm,
the Rosemount 2120 meets the most stringent hygienic requirements used in food and
beverage, and pharmaceutical applications. The Rosemount 2120 is robust enough to
easily withstand CIP (Clean-In- Place) and SIP (Steam-In-Place) cleaning routines.
Rosemount 2120 Level Switch 11
J
A
B
C
D, E
F
G, H
I
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March 2022 00809-0100-4030
2.5 Components of the level switch
Figure 2-1 shows the components of a Rosemount 2120.
Figure 2-1: Rosemount 2120 Features
A. Direct Load, Relay DPCO, PLC/PNP, NAMUR, or 8/16 mA electronics
Visible heartbeat LED
B.
C.
Mode switch, adjustable time delay
D. Housings in glass-filled nylon, aluminum, or 316 SST
E. Magnetic test point
F. Threaded, flanged, or Tri Clamp process connections
G. ‘Fast drip’ fork design
H. Wetted material in 316/316L stainless steel, Alloy C and Alloy C-276, or ECTFE-coated
316/316L stainless steel
I. Short fork length or extensions up to 157.5-in. (4 m)
J. Two cable/ conduit entries
2.5.1 Short fork technology
Using short-fork technology, the device can be used in almost all liquid applications.
Extensive research has maximized the operational effectiveness of the fork design, making
it suitable for most liquid mediums including coating liquids, aerated liquids, and slurries.
2.5.2 Fork design
The “fast drip” design allows the liquid to be quickly drawn away from the fork tip, making
the Rosemount 2120 quicker and more responsive in high density or viscous liquid
applications.
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Figure 2-2: “Fast drip” forks
2.5.3 Heartbeat LED
Each electronics cassette of the level switch has a ‘heartbeat’ LED indicating its operation
status, which can always be seen from all angles through a lens in the cover of non-metal
housings. The LED flashes when the level switch output is ‘off’ and is constantly lit when
'on'.
The LED gives a constant indication that the level switch is functioning correctly (different
flash rates are used to indicate a product malfunction) and gives a local indication of the
process state.
2.5.4 Mode switch and adjustable output delay
A mode switch on the electronics cassette allows the level switch output to be 'on' or 'off'
when the forks are wet or dry. Typically is set to 'dry on' (for a low-level point alarm) or 'wet
on' (for a high-level point alarm). There is also a user-selectable time delay (0.3, 1, 3, 10, or
30 seconds) on the electronics cassette to virtually eliminate the risk of false switching in
turbulent or splashing applications.
2.5.5 Magnetic test point
A magnetic test point is located on the side of the housing, allowing a functional test of
the Rosemount 2120 and a system connected to it. Holding a magnet to the test point
causes the output to change state.
2.5.6 Electrical connections
The terminal blocks extend above the housing and give easy terminal access. Electrical
protections make electrical hook-up safe and easy.
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Reference Manual Mechanical installation
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3 Mechanical installation
3.1 Safety messages
Instructions and procedures in this section may require special precautions to ensure the
safety of the personnel performing the operations. Information that potentially raises
safety issues is indicated by a warning symbol ( ). Refer to the following safety messages
before performing an operation preceded by this symbol.
WARNING
Failure to follow safe installation and servicing guidelines could result in death or
serious injury.
Ensure the level switch is installed by qualified personnel and in accordance with
applicable code of practice.
Use the level switch only as specified in this manual. Failure to do so may impair the
protection provided by the level switch.
The weight of a level switch with a heavy flange and extended fork length may exceed 37
lb. (18 kg). A risk assessment is required before carrying, lifting, and installing the level
switch.
Repair, e.g. substitution of components, etc. may jeopardize safety and is under no
circumstances allowed.
WARNING
Explosions could result in death or serious injury.
Verify the operating atmosphere of the level switch is consistent with the appropriate
hazardous locations certifications.
Before connecting a handheld communicator in an explosive atmosphere, ensure the
instruments are installed in accordance with intrinsically safe or non-incendive field wiring
practices.
In explosion-proof/flameproof and non-incendive installations, do not remove the housing
cover when power is applied to the level switch.
The housing cover must be fully engaged to meet flameproof/explosion-proof
requirements.
Rosemount 2120 Level Switch 15
Mechanical installation Reference Manual
March 2022 00809-0100-4030
WARNING
Electrical shock could cause death or serious injury.
Avoid contact with the leads and terminals. High voltage that may be present on leads can
cause electrical shock.
Ensure the power to the level switch is off, and the lines to any other external power
source are disconnected or not powered while wiring the level switch.
Ensure the wiring is suitable for the electrical current and the insulation is suitable for the
voltage, temperature, and environment.
WARNING
Process leaks could result in death or serious injury.
Ensure the level switch is handled carefully. If the process seal is damaged, gas might
escape from the vessel (tank) or pipe.
WARNING
Physical access
Unauthorized personnel may potentially cause significant damage to and/or
misconfiguration of end users’ equipment. This could be intentional or unintentional and
needs to be protected against.
Physical security is an important part of any security program and fundamental to
protecting your system. Restrict physical access by unauthorized personnel to protect end
users’ assets. This is true for all systems used within the facility.
CAUTION
Hot surfaces
The flange and process seal may be hot at high process temperatures. Allow to cool before
servicing.
3.2 Installation considerations
Before installing the level switch, review the safety, environmental, application, and preinstallation sections.
3.2.1 Environmental considerations
The Rosemount 2120 is weatherproof and protected against the ingress of dust, but must
be protected from flooding. Avoid installing the level switch near heat sources.
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Figure 3-1: Environmental Considerations
3.2.2 Application considerations
The Rosemount 2120 is a wired point-level device for use on open or closed vessels (tanks)
and in pipework containing liquid mediums.
For most liquids, including coating, aerated liquids and slurries, the function is virtually
unaffected by flow, turbulence, bubbles, foam, vibration, solid particles, build-up, or
properties of the liquid medium.
Avoid process medium build-up on the forks
Avoid situations where a drying and coating process medium may create an excessive
build-up or implement preventative maintenance programs to ensure the build-up is not
enough to impair performance (see Figure 3-2).
Rosemount 2120 Level Switch 17
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Always ensure:
• There is sufficient distance between build-up on the tank wall and the fork.
• There is no risk of ‘bridging’ the level switch forks.
Examples of products that can create ‘bridging’ of forks and impair performance are
dense paper slurries and bitumen.
Figure 3-2: Avoid Product Build-up
Operating temperature and pressure ranges
Ensure the process is operating within the instrument operating temperature and pressure
ranges.
Liquid density requirements
Minimum liquid density is 37.5 lb/ft3 (600 kg/m3).
Liquid viscosity range
Up to 10000 cP (centiPoise)
Solids content in the liquid medium
As a guideline, the maximum solid particle diameter in the liquid process medium is 0.2 in.
(5 mm). Extra consideration is needed when solid particles are bigger than 0.2 in. (5 mm)
and advice should be sought from Emerson.
Foams
In almost all cases, the Rosemount 2120 is insensitive to foams (i.e. does not see the
foam).
However in rare occasions, some very dense foams may be seen as liquid; known examples
of this are found in ice-cream and orange juice manufacturing.
18 Reference Manual
SP
HYSP
0.5
(13)
0.1
(2.5)
0.5
(13)
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Switching point
The switching point varies with different liquid densities. The switching point (SP) and
hysteresis (HY) for water are shown in Figure 3-3.
Figure 3-3: Switching Point in Inches (Millimeters)
Note
When mounted vertically, a low density medium has a switching point closer to the
process connection. A high density medium has a switching point closer to fork tip.
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3.2.3 Pre-installation considerations
Measurement accuracy is dependent upon the proper installation of the device. Keep in
mind the need for easy access, personnel safety, practical field calibration, and a suitable
environment for the device.
Device identification
To identify a version of the level switch, see the labels on the housing and on the
electronics cassette inside the housing.
How to handle a level switch
Handle the level switch with great care.
The weight of the level switch with a heavy flange and extended fork length may exceed
37 lb. (18 kg). A risk assessment is required to be done before carrying, lifting, and
installing the level switch.
Use both hands to carry the extended length versions, and do not hold a level switch by
the forks (see Figure 3-4).
Figure 3-4: Handling
Make no alterations to the level switch
Never make any alterations to the mechanical or electrical features of the level switch.
Figure 3-5: Make No Alterations
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Allow adequate space outside tank or pipe
Mount the level switch so that it is removable and allow easy access to the wiring terminals
when the top cover is removed. Ensure there is also enough room for fitting cable glands
and cables.
A clearance of 1.2 in. (30 mm) is required for the top cover to be removed.
Note
Versions of the level switch with a glass-filled-nylon housing can be rotated to assist with
the cabling.
Covers installation
Ensure the housing O-ring is sitting evenly and then tighten the electronics housing cover
to form a good seal. On metal housing versions, metal must contact metal to form a good
seal. Always use Emerson's O-rings.
Mounting orientation
Mount the Rosemount 2120 at any angle that allows the level of the process medium to
rise, fall, or flow through the fork gap.
Related information
Correct fork alignment
Hygienic installation
For hygienic applications, the level switch must be hygienically cleaned before installation
and handled in strict accordance with hygienic standards.
Refer to the Rosemount 2120 Product Certifications document for hygienic approvals and
compliance requirements.
Rosemount 2120 Level Switch 21
A A
B
D
A
B
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March 2022 00809-0100-4030
Insulation
Figure 3-6: Insulation
A. 3.9 in. (100 mm) clearance all around
B. ROCKWOOL
®
Pipe installation requirements
• The inside pipe diameter (D) must be 1.4 in. (35 mm) or larger.
• Ensure the fork tines intrude at least 0.9 in. (22 mm) into the pipe.
• Keep at least 0.3 in. (7 mm) of clearance between the fork tines and the pipe wall.
Figure 3-7: Pipe Installation
A. Minimum intrusion 0.9 in. (22 mm)
Minimum clearance 0.3 in. (7 mm)
B.
22 Reference Manual
A
B
B
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Other recommendations
• Always install in the normally “on” state.
— High-level alarm: recommended Mode setting is Dry = on.
— Low-level alarm: recommended Mode setting is Wet = on.
• Avoid:
— Installing near to liquid entering the tank at the filling-point.
— Heavy splashing on the forks.
Increasing the sensor output delay reduces accidental detection caused by splashing.
• Always ensure:
— The overall system is tested during commissioning by using the local magnetic test
point.
— The installation does not create tank crevices around the forks where a liquid
medium may collect. This event can happen with high-viscosity and high-density
liquids.
— The forks do not come into contact with the vessel (tank) or pipe wall, internal
fittings, or any other obstructions.
• Extra consideration is needed if the plant vibration is close to the 1400 Hz operating
frequency of the fork.
Required supports for extended fork
Supporting the extended fork avoids long fork length vibration.
Figure 3-8: Vertical Installation (Standard)
A. Maximum 3.28 ft. (1.0 m)
Rosemount 2120 Level Switch 23
B. 3.28 ft. (1.0 m)
A
B
B
B
C
A
B B
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Figure 3-9: Vertical Installation (Marine GL Approved)
A. Maximum 1.3 ft. (0.4 m)
B. 2.3 ft. (0.7 m)
0.65 ft. (0.2 m)
C.
Figure 3-10: Horizontal Installation (Standard)
A. Maximum 3.28 ft. (1.0 m)
B. 3.28 ft. (1.0 m)
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BC B B
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Figure 3-11: Horizontal Installation (Marine GL Approved)
A. Maximum 1.3 ft. (0.4 m)
B. 2.3 ft. (0.7 m)
C.
0.65 ft. (0.2 m)
Rosemount 2120 Level Switch 25
F
B
A
C
D
E
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3.3 Installation procedures
3.3.1 Process connection seals
Figure 3-12: Process Connection Seals
A. PTFE tape
B. NPT or BSPT (R) thread
Gasket
C.
D. BSPP (G) thread
E. Tri Clamp
F. The Tri Clamp seal is supplied in an accessory kit
26 Reference Manual
A
B
A
B
OK
OK
A
B
C
OK OK
OK
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3.3.2 Correct fork alignment
Fork alignment in a pipe installation
The fork is correctly aligned by positioning the groove or notch as indicated (Figure 3-13).
Figure 3-13: Correct Fork Alignment for Pipe Installation
A. Tri Clamp process connections have a circular notch
B. Threaded process connections have a groove
Fork alignment in a vessel (tank) installation
The fork is correctly aligned by positioning the groove or notch as indicated (Figure 3-14).
Figure 3-14: Correct Fork Alignment for Vessel (Tank) Installation
A. Tri Clamp process connections have a circular notch
B. Threaded process connections have a groove
Flanged process connections have a circular notch
C.
Rosemount 2120 Level Switch 27
A
A
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3.3.3 Mounting the threaded version
Threaded vessel (tank) or pipework connection
Procedure
1. Seal and protect the threads. Use anti-seize paste or PTFE tape according to site
procedures.
A gasket may be used as a sealant for BSPP (G) threaded connections.
2. Screw the level switch into the process connection.
Note
Tighten using the hexagon nut only.
Figure 3-15: Vertical Installation
A. Gasket for BSPP (G) threaded connection
Figure 3-16: Horizontal Installation
A. Gasket for BSPP (G) threaded connection
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A
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Threaded flange connection
Procedure
1. Place the customer-supplied flange and gasket on the vessel (tank) nozzle.
A. Gasket (customer supplied)
2. Tighten the bolts and nuts with sufficient torque for the flange and gasket.
3. Seal and protect the threads. Use anti-seize paste or PTFE tape according to site
procedures.
A gasket may be used as a sealant for BSPP (G) threaded connections.
Rosemount 2120 Level Switch 29
A
A
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4. Screw the level switch into the flange thread.
Note
Tighten using the hexagon nut only.
A. Gasket for BSPP (G) threaded connection
3.3.4 Mounting the flanged version
Procedure
1. Lower the level switch into the nozzle.
A. Gasket (customer supplied)
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A
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2. Tighten the bolts and nuts with sufficient torque for the flange and gasket.
3.3.5 Mounting the Tri Clamp version
Procedure
1. Lower the level switch into the flange face.
A. Seal (supplied with Tri Clamp)
2. Fit the Tri Clamp.
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4 Electrical installation
4.1 Safety messages
Instructions and procedures in this section may require special precautions to ensure the
safety of the personnel performing the operations. Information that potentially raises
safety issues is indicated by a warning symbol ( ). Refer to the following safety messages
before performing an operation preceded by this symbol.
WARNING
Failure to follow safe installation and servicing guidelines could result in death or
serious injury.
Ensure the level switch is installed by qualified personnel and in accordance with
applicable code of practice.
Use the level switch only as specified in this manual. Failure to do so may impair the
protection provided by the level switch.
The weight of a level switch with a heavy flange and extended fork length may exceed 37
lb. (18 kg). A risk assessment is required before carrying, lifting, and installing the level
switch.
Repair, e.g. substitution of components, etc. may jeopardize safety and is under no
circumstances allowed.
WARNING
Explosions could result in death or serious injury.
Verify the operating atmosphere of the level switch is consistent with the appropriate
hazardous locations certifications.
Before connecting a handheld communicator in an explosive atmosphere, ensure the
instruments are installed in accordance with intrinsically safe or non-incendive field wiring
practices.
In explosion-proof/flameproof and non-incendive installations, do not remove the housing
cover when power is applied to the level switch.
The housing cover must be fully engaged to meet flameproof/explosion-proof
requirements.
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March 2022 00809-0100-4030
WARNING
Electrical shock could cause death or serious injury.
Avoid contact with the leads and terminals. High voltage that may be present on leads can
cause electrical shock.
Ensure the power to the level switch is off, and the lines to any other external power
source are disconnected or not powered while wiring the level switch.
Ensure the wiring is suitable for the electrical current and the insulation is suitable for the
voltage, temperature, and environment.
WARNING
Process leaks could result in death or serious injury.
Ensure the level switch is handled carefully. If the process seal is damaged, gas might
escape from the vessel (tank) or pipe.
WARNING
Physical access
Unauthorized personnel may potentially cause significant damage to and/or
misconfiguration of end users’ equipment. This could be intentional or unintentional and
needs to be protected against.
Physical security is an important part of any security program and fundamental to
protecting your system. Restrict physical access by unauthorized personnel to protect end
users’ assets. This is true for all systems used within the facility.
CAUTION
Hot surfaces
The flange and process seal may be hot at high process temperatures. Allow to cool before
servicing.
4.2 Prepare the electrical connections
4.2.1 Cable selection
Use 26–14 AWG (0.13 to 2.5 mm2) AWG wiring. Twisted-pairs and shielded wiring is
recommended for environments with high EMI (electromagnetic interference). Two wires
can be safely connected to each terminal screw.
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4.2.2 Cable glands/conduits
For intrinsically safe, explosion-proof/flameproof, and dust-proof installations, only use
certified cable glands or conduit entry devices. Ordinary location installations can use
suitably rated cable glands or conduit entry devices to maintain the Ingress Protection (IP)
rating.
Unused conduit entries must always be sealed with a suitably rated blanking/stopping
plug.
Note
Do not run signal wiring in conduit or open trays with power wiring or near heavy electrical
equipment.
4.2.3 Power supply
The power supply requirements are dependent on the electronics selected.
• Direct load switching: 20 - 60 Vdc or 20 - 264 Vac (50/60 Hz)
• PNP/PLC electronics: 20 - 60 Vdc
• Relay DPCO (Double Pole Changeover) electronics (standard): 20 - 60 Vdc or
20 - 264 Vac (50/60 Hz)
• Relay DPCO electronics (12 Vdc nominal): 9 - 30 Vdc
• NAMUR electronics: 8 Vdc
• 8/16 mA electronics: 24 Vdc
4.2.4 Hazardous areas
When the device is installed in hazardous areas (classified locations), local regulations and
the conditions-of-use specified in applicable certificates must be observed. Review the
Rosemount 2120 Product Certifications document for information.
4.2.5 Wiring diagrams
CAUTION
• Before use, check the cable glands and blanking plugs are suitably rated.
• Isolate supply before connecting the switch or removing the electronics.
• The Protective Earth (PE) terminal must be connected to an external earthing
system.
Note
When replacing a cassette, it is important to re-calibrate.
Rosemount 2120 Level Switch 35
1 2 3
LN
0V
I
L
DPST
+V
Fuse 2A(T)R
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March 2022 00809-0100-4030
Direct load switching cassette
Figure 4-1: Direct Load Switching (2-wire) Cassette (Red Label) – Code T
R = External load (must be fitted)
N = Neutral
L = Live
Note
A DPST (Double Pole, Single Throw) on/off switch must be fitted for safe disconnection of
the power supply. Fit the DPST switch as near as possible to the level switch. Keep the
DPST switch free of obstructions. Label the DPST switch to indicate it is the supply
disconnection device for the level switch.
Note
The Rosemount 2120 requires a minimum current to operate (I
), which continues to
OFF
flow when the output is ‘off’. If selecting a relay to wire in series with the Rosemount 2120,
ensure the drop-out voltage of the relay is greater than the voltage generated across the
relay coil when I
flows through it.
OFF
Table 4-1: Electrical Parameters
Parameter Value
U 20 - 60 Vdc or 20 - 264 Vac (50/60 Hz)
I
I
I
OFF
L
PK
< 4 mA
20 - 500 mA
5 A, 40 ms (inrush)
36 Reference Manual
1 2
I
L
R
N
0 VL+ V
F
3
DPST
U
12 V
1 2
I
L
R
N
0 VL+ V
F
3
DPST
< 4 mA
1 2
I
L
R
N
0 VL+ V
F
3
DPST
U
12 V
1 2
I
L
R
N
0 VL+ V
F
3
DPST
< 4 mA
= Load on
= Load off
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Table 4-2: Direct Load Functions
Mode: dry on, high level alarm Mode: wet on, low level alarm
LED on continuously LED flashes every second LED on continuously LED flashes every second
Rosemount 2120 Level Switch 37
Wet On Mode
+V
1
2 3 4
O/P 0V
F
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PNP/PLC cassette
Figure 4-2: PNP/PLC (3-wire) Cassette (Yellow Label) – Code G
F = Fuse 2A(T)
Table 4-3: Electrical Parameters
Parameter Value
U 20 - 60 Vdc
I < 4 mA + I
I
L (OFF)
I
L(MAX)
I
PK
U
OUT(ON)
< 100 μA
0 - 500 mA
5 A, 40 ms (inrush)
U - 2.5 Vdc (20 °C)
U - 2.75 Vdc (-40 to 80 °C)
L
38 Reference Manual
1 2
-
I/P
PLC
+
3 4
I
L
< 3 V
U
1 2
-
I/P
PLC
+
3 4
I
L
<100 μA
1 2
-
I/P
PLC
+
3 4
I
L
< 3 V
U
1 2
-
I/P
PLC
+
3 4
I
L
<100 μA
1 2
3 4
R
F
< 3 V
U
I
L
1 2
-+
3 4
R
F
I
L
<100 μA
1 2
-
+
3 4
R
F
< 3 V
U
I
L
1 2
-+
3 4
R
F
I
L
<100 μA
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Table 4-4: PNP/PLC Cassette Functions
Mode: dry on, high level alarm Mode: wet on, low level alarm
PLC (positive input)
PNP dc
LED
LED on continuously LED flashes every second LED on continuously LED flashes every second
Rosemount 2120 Level Switch 39
LN
0V
Fuse 0.5 (T)
DPST
+V
1
2 3
4
5 6
7
8 9
NC
C NO
NC
C NO
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Relay DPCO cassette (standard version)
Figure 4-3: Relay DPCO Cassette, Standard Version (Green Label) – Code V
Note
A DPST (Double Pole, Single Throw) on/off switch must be fitted for safe disconnection of
the power supply. Fit the DPST switch as near as possible to the level switch. Keep the
DPST switch free of obstructions. Label the DPST switch to indicate it is the supply
disconnection device for the level switch.
Table 4-5: Electrical Parameters
Parameter Value
U 20 - 60 Vdc or 20 - 264 Vac (50/60Hz)
I < 6 mA
Table 4-6: NC, C, and NO Terminals
Parameter Resistive load Inductive load
cos ϕ 1 0.4
L/R 0 ms 7 ms
I
MAX
U
P
MAX
MAX
ac 250 V 250 V
dc 30 V 30 V
ac 1250 VA 875 VA
dc 240 W 170 W
5 A 3.5 A
40 Reference Manual
NC C NO
NC C NO
NC C NO
NC C NO
NC C NO
NC C NO
NC C NO
NC C NO
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Table 4-7: Relay Cassette Functions
Mode: dry on, high level alarm Mode: wet on, low level alarm
LED on continuously LED flashes every second LED on continuously LED flashes every second
Rosemount 2120 Level Switch 41
NC
C NO
NC
C NO
0V
Fuse 0.5 (T)
DPST
+V
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Relay DPCO cassette (12 Vdc nominal version)
Figure 4-4: Relay DPCO Cassette, 12 Vdc Nominal Version (Green Label) – Code E
Note
A DPST (Double Pole, Single Throw) on/off switch must be fitted for safe disconnection of
the power supply. Fit the DPST switch as near as possible to the Rosemount 2120. Keep
the DPST switch free of obstructions. Label the DPST switch to indicate it is the supply
disconnection device for the Rosemount 2120.
Table 4-8: Electrical Parameters
Parameter Value
U 9 - 30 Vdc
I < 4 mA
Table 4-9: NC, C, and NO Terminals
Parameter Resistive load Inductive load
cos ϕ 1 0.4
L/R 0 ms 7 ms
I
MAX
U
P
MAX
MAX
2 A 1 A
30 V 30 V
60 W 30 W
42 Reference Manual
NC C NO
NC C NO
NC C NO
NC C NO
NC C NO
NC C NO
NC C NO
NC C NO
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Table 4-10: Relay Cassette Functions
Mode: dry on, high level alarm Mode: wet on, low level alarm
LED on continuously LED flashes every second LED on continuously LED flashes every second
Rosemount 2120 Level Switch 43
A
+
-
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NAMUR cassette
Figure 4-5: NAMUR Cassette (Light Blue Label) – Code K
A. A certified intrinsically safe isolating amplifier to IEC 60947-5-6
Note
• This cassette is suitable for Intrinsically Safe (IS) applications and requires a certified
isolating barrier. See the Rosemount 2120 Product Certifications document for
Intrinsically Safe approvals.
• This electronics cassette is also suitable for non-hazardous (safe) area applications.
• It can only be interchanged with the 8/16 mA cassette.
• Do not exceed 8 Vdc.
Table 4-11: Electrical Parameters
Parameter Value
I
ON
I
OFF
I
FAULT
2.2 - 2.5 mA
0.8 - 1.0 mA
< 1.0 mA
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1 2
> 2.2 mA
(-) (+)
1 2
< 1.0 mA
(-) (+)
1 2
> 2.2 mA
(-) (+)
1 2
< 1.0 mA
(-) (+)
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Table 4-12: NAMUR Cassette Functions
Mode: dry on, high level alarm Mode: wet on, low level alarm
LED on continuously LED flashes every second LED on continuously LED flashes every second
Rosemount 2120 Level Switch 45
1 2
3
A
+
-
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8/16 mA cassette
Figure 4-6: 8/16 mA Cassette (Dark Blue Label) – Code H
A. A certified intrinsically safe isolating amplifier to IEC 60947-5-6
Note
• This cassette is suitable for Intrinsically Safe (IS) applications and requires a certified
isolating barrier. See the Rosemount 2120 Product Certifications document for
Intrinsically Safe approvals.
• This electronics cassette is also suitable for non-hazardous (safe) area applications. In
this case, U = 11 - 36 Vdc.
• It can only be interchanged with a NAMUR cassette.
Table 4-13: Electrical Parameters
Parameter Value
U 24 Vdc Nominal
I
ON
I
OFF
I
FAULT
15 - 17 mA
7.5 - 8.5 mA
< 3.7 mA
46 Reference Manual
2
(-) (+)
31
> 15 mA
2
(-) (+)
31
< 8.5 mA
2
(-) (+)
31
> 15 mA
2
(-) (+)
31
< 8.5 mA
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Table 4-14: 8/16 mA Cassette Functions
Mode: dry on, high level alarm Mode: wet on, low level alarm
LED on continuously LED flashes every second LED on continuously LED flashes every second
Rosemount 2120 Level Switch 47
B
A
CC
D
B
A
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4.2.6 Grounding
Make sure grounding is done according to national and local electrical codes. Failure to do
so may impair the protection provided by the equipment.
Signal cable shield grounding
Make sure the instrument cable shield is:
• Trimmed close and insulated from touching the housing.
• Continuously connected throughout the segment.
• Connected to a good earth ground at the power supply end.
Figure 4-7: Signal Cable Shield Grounding at Power Supply End
A. Trim shield and insulate
B. Minimize distance
Trim shield
C.
D. Connect shield back to the power supply ground
Grounding the housing
The most effective grounding method for the metal housing is a direct connection to
earth ground with minimal impedance. Housings with NPT conduit entries do not have an
earth ground point and must use the fork earth.
Figure 4-8: Ground Screws
A. External ground screw
4.3 Connect wiring and power up
Procedure
1. Verify the power supply is disconnected.
48 Reference Manual
¾-in. ANPTM20 x 1.5
M20
¾-in. ANPTM20 x 1.5
M20
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2. Remove the field terminals cover.
In an explosion-proof/flameproof installation, do not remove the level switch cover
when power is applied to the unit. The cover must also not to be removed in
extreme environmental conditions.
• Versions of the Rosemount 2120 with a metal housing are explosion-proof/
flameproof. They have a cover-lock to be undone first.
• Versions of the Rosemount 2120 with a glass-filled-nylon housing are not
explosion-proof/flameproof. They do not have a cover-lock.
3. Remove the plastic plugs.
Versions of the Rosemount 2120 with a glass-filled-nylon housing do not have
plastic plugs fitted.
4. Pull cables through the cable gland/conduits.
• Cassettes with a single terminal only require one cable.
Identification of thread size and type:
Rosemount 2120 Level Switch 49
• Cassettes with two or more terminals may require more than one cable.
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5. Connect the cable wires (see Wiring diagrams for other cassettes).
Metal housing:
Glass-filled-nylon housing:
6. Ensure proper grounding.
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7. Tighten the cable glands.
Apply PTFE tape or other sealant to the threads.
Metal housing:
Glass-filled-nylon housing:
Note
Make sure to arrange the wiring with a drip loop.
Rosemount 2120 Level Switch 51
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8. Plug and seal the unused conduit connection to avoid moisture and dust
accumulation inside the housing.
Apply PTFE tape or other sealant to the threads.
Metal housing:
Glass-filled-nylon housing:
9. Attach and tighten the cover.
Make sure the cover is fully engaged.
10. Required for explosion-proof/flameproof installations only:
The cover must be fully engaged to comply with explosion-proof requirements.
11. Re-lock the cover.
12. Connect the power supply.
52 Reference Manual
OPERATION MODE
Dry On Mode
Dry
Wet
Wet On Mode
Dry
Wet
Dry On Wet On
Seconds Delay
0.3 0.3
3
3
0
1
0
1
3
30
10
1
1 2
3
OUT
+
-
4
PLC/PNP
Isolate Supply
Before Removing
A B
Dry On Wet On
Seconds Delay
0.3 0
.3
3
30
1
0
1
3
30
10
1
A
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5 Operation
5.1 Output mode and time delay
All electronics cassettes have a rotating switch for setting the output to be "Dry On" (on
when the fork is sufficiently dry) or "Wet On" (on when the fork is sufficiently wet).
The electronics uses hysteresis to help prevent constant switching of the output from dryto-wet and wet-to-dry states due to splashing or intermediate conditions. To further
prevent false switching, the rotating switch also sets a time delay of up to 30 seconds
before the output changes.
A small cut-out in the rotating switch indicates the present mode and time delay.
Figure 5-1: Top-down View: Example Cassette Inside Housing
A. 'Heartbeat' LED
B. Rotating switch for setting output mode and time delay
The recommended mode for high level alarm installations is the "Dry On" mode (Figure
5-2).
Figure 5-2: Typical Settings for High Level Applications
A. Mode “Dry On” and 1 second time delay
The "Wet On" mode is recommended for low level alarm installations (Figure 5-3).
Rosemount 2120 Level Switch 53
Dry On Wet On
Seconds Delay
0.3 0
.3
30
10
3
30
10
1
3
1
A
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Figure 5-3: Typical Settings for Low Level Applications
A. Mode “Wet On” and 1 second time delay
5.1.1 Set the mode switch and switching time delay
Procedure
1. Select “Dry on” or “Wet on” mode.
Select 0.3, 1, 3, 10, or 30 seconds for the delay before switching output state.
2.
Note
There is a five second delay before changes to the mode and time delay become
active.
5.2 LED indication status
Table 5-1 shows the different operation statuses and how they are indicated by the LED.
Table 5-1: LED Indications
LED flash rate Switch status
Continuous Output state is on.
1 every second Output state is off.
1 every 2 seconds Uncalibrated.
1 every 4 seconds Load fault; load current too high; load short
2 times / second Indication of successful calibration.
3 times / second Internal PCB fault.
circuit.
Off Problem (e.g. supply).
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6 Service and troubleshooting
6.1 Safety messages
Instructions and procedures in this section may require special precautions to ensure the
safety of the personnel performing the operations. Information that potentially raises
safety issues is indicated by a warning symbol ( ). Refer to the following safety messages
before performing an operation preceded by this symbol.
WARNING
Failure to follow safe installation and servicing guidelines could result in death or
serious injury.
Ensure the level switch is installed by qualified personnel and in accordance with
applicable code of practice.
Use the level switch only as specified in this manual. Failure to do so may impair the
protection provided by the level switch.
The weight of a level switch with a heavy flange and extended fork length may exceed 37
lb. (18 kg). A risk assessment is required before carrying, lifting, and installing the level
switch.
Repair, e.g. substitution of components, etc. may jeopardize safety and is under no
circumstances allowed.
WARNING
Explosions could result in death or serious injury.
Verify the operating atmosphere of the level switch is consistent with the appropriate
hazardous locations certifications.
Before connecting a handheld communicator in an explosive atmosphere, ensure the
instruments are installed in accordance with intrinsically safe or non-incendive field wiring
practices.
In explosion-proof/flameproof and non-incendive installations, do not remove the housing
cover when power is applied to the level switch.
The housing cover must be fully engaged to meet flameproof/explosion-proof
requirements.
Rosemount 2120 Level Switch 55
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WARNING
Electrical shock could cause death or serious injury.
Avoid contact with the leads and terminals. High voltage that may be present on leads can
cause electrical shock.
Ensure the power to the level switch is off, and the lines to any other external power
source are disconnected or not powered while wiring the level switch.
Ensure the wiring is suitable for the electrical current and the insulation is suitable for the
voltage, temperature, and environment.
WARNING
Process leaks could result in death or serious injury.
Ensure the level switch is handled carefully. If the process seal is damaged, gas might
escape from the vessel (tank) or pipe.
WARNING
Physical access
Unauthorized personnel may potentially cause significant damage to and/or
misconfiguration of end users’ equipment. This could be intentional or unintentional and
needs to be protected against.
Physical security is an important part of any security program and fundamental to
protecting your system. Restrict physical access by unauthorized personnel to protect end
users’ assets. This is true for all systems used within the facility.
CAUTION
Hot surfaces
The flange and process seal may be hot at high process temperatures. Allow to cool before
servicing.
6.2 Magnetic test point
A magnetic test point is marked on the side of the housing to allow a functional test of the
Rosemount 2120 in the overall system. By touching a magnet to the target, the output
from the level switch will change state while the magnet is present.
56 Reference Manual
MAGNETIC
TEST
POINT
MAGNETIC
TEST
POINT
A
B
B
A
MAGNETIC
TEST
POINT
S
N
S
N
TP
TP
TP
S
N
S
N
A
B
B
A
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Figure 6-1: Magnetic Test Point (Glass-filled Nylon Housing)
A. Output off
B. Output on
Figure 6-2: Magnetic Test Point (Metal Housing)
A. Output off
B. Output on
Rosemount 2120 Level Switch 57
OK
OK
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6.3 Visual inspection
Visually examine the level switch and do not use if it is damaged. Check:
• The housing cover, cable glands, and blanking plugs are fitted securely.
• The LED flash rate is once every second or continually on.
Figure 6-3: Visual Inspection
Related information
LED indication status
6.4 Maintenance
Figure 6-4: Maintenance
Note
Only use a soft type brush for cleaning.
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6.5 Troubleshooting
6.5.1 Does not switch
Symptom or indication
LED is not lit, no power.
Recommended actions
1. Check the power supply.
2.
Check the load on direct load switching electronics model.
Symptom or indication
LED is flashing three times per second.
Recommended actions
Contact Emerson to report an internal PCB fault is being indicated.
Symptom or indication
LED is flashing once every two seconds.
Recommended actions
Contact Emerson to report an uncalibrated device is being indicated.
Symptom or indication
LED is flashing once every four seconds.
Recommended actions
Check the electrical installation for a load fault (current is too high or a short-circuit).
Symptom or indication
Visual inspection found fork damage.
Recommended actions
Contact Emerson to report the damage and discuss how to get a replacement.
Symptom or indication
Visual inspection found thick encrustation on the forks.
Recommended actions
Carefully clean the fork.
Symptom or indication
There is always a five second delay after changing the mode or delay.
Recommended actions
This is a normal function when making any changes to the settings.
Rosemount 2120 Level Switch 59
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March 2022 00809-0100-4030
Related information
LED indication status
6.5.2 Incorrect switching
Symptom or indication
Dry = On, Wet = On is set incorrectly.
Recommended actions
Set the correct mode on the electronics cassette.
6.5.3 Faulty switching
Symptom or indication
Turbulence.
Recommended actions
Set a longer switching time delay.
Symptom or indication
Excessive electrical noise.
Recommended actions
Suppress the cause of the interference.
Symptom or indication
Cassette has been fitted from another level switch.
Recommended actions
Fit the factory supplied cassette and then calibrate.
6.6 Spare parts
See the Rosemount 2120 Product Data Sheet for the latest information about spare parts.
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6.7 Replacement and calibration of cassettes
When replacing a damaged or faulty electronics cassette, it is necessary to calibrate the
replacement cassette to the operating frequency of the fork sensor.
6.7.1 Replace the cassette
Prerequisites
If this replacement is taking place in a hazardous area, only qualified personnel should
perform the replacement. All work in hazardous areas must be carried out in accordance
to national and local codes of practice.
Calibration of this device is complex and it may take several attempts before success.
On Intrinsically Safe (I.S.) approved versions of the level switch, it is recommended that
replacement and calibration is performed in a non-hazardous (safe) area.
Note
• In I.S. applications, NAMUR cassettes can only be replaced with NAMUR cassettes, and
8/16 mA cassettes can only be replaced by 8/16 mA cassettes.
• Non-I.S. cassettes can be interchanged with other non-I.S. cassettes, but the new label
must be fitted and the original part number transferred to the new label.
• Before starting the replacement and calibration procedure, ensure that any controlled
process will not be adversely affected.
Procedure
1. Isolate and disconnect the power to the Rosemount 2120, and insulate the ends of
the wires as a safety precaution.
There may be more than one power source connected to a relay cassette.
2.
Remove the housing cover and disconnect the wires from the cassette.
Make a note of the connections and mode switch position (see Figure 6-5).
Figure 6-5: Mode Switch Setting (Existing Cassette)
This is an example of how the existing cassette may look. Here, the mode switch is
set to “Dry On” with a one second delay.
Take note of the actual setting.
SETTING IS: ____________________________________
3. Remove and retain the two fixing screws from the base of the cassette, and then
unplug the cassette.
Rosemount 2120 Level Switch 61
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4. Plug in the replacement cassette, secure it with the two screws.
5. Reconnect the wiring.
6.
Set the mode switch to “Wet On” with a one second delay, ready for calibration (see
Figure 6-6).
Figure 6-6: Mode Switch Setting (Replacement Cassette)
7. Reconnect the power supplies to the Rosemount 2120.
6.7.2 Calibrate the replacement cassette
Prerequisites
Some of the calibration sequence steps are time-dependent and must be carried out
within the noted times. The purpose of the time dependency and switching sequence is to
prevent an accidental calibration from occurring.
Verify:
• The sensor forks are clean and dry.
• The mode switch is set to “Wet On” with the time delay set to one second.
Procedure
1. Verify the 'heartbeat' LED is flashing at a rate of one flash per second.
Proceed to
2. Apply a magnet to the test-point.
After a one second delay, the LED will be lit continuously.
3. Within one second, rotate the mode switch two steps clockwise.
The LED will go out within two seconds.
4. Within three seconds, rotate the mode switch two steps counter-clockwise.
Proceed to Step 8.
After a two second delay, the LED should start flashing twice per second.
5. Apply a magnet to the test-point.
After a one second delay, the LED will flash once every second.
6. Within one second, rotate the mode switch two positions clockwise.
The LED will go out within two seconds.
Step 5 if it is on continuously.
7. Within three seconds, rotate the mode switch two steps counter-clockwise.
After a two second delay, the LED should start flashing twice per second.
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8. If the LED is flashing twice per second, the calibration has worked correctly.
a) Remove the magnet from the test-point.
b)
After a one second delay, the unit will return to normal operation. Proceed to
Step 11.
9. If the LED is flashing once per second or it is on continuously, the calibration has
failed:
a) Remove the magnet from the test-point.
b) Wait ten seconds, and then re-try from Step 2.
10. If the LED is not lit (after the two seconds delay in Step 7):
a) Check the sensor forks are clean and dry.
b) Check if anything is jamming or touching the sensor forks.
c) Contact Customer Support at Emerson if no fault is found.
11. Set the mode switch to the original setting and wait five seconds.
12. Replace the housing cover and check that the system works.
Related information
Magnetic test point
6.8 Opening the lid (cover)
Before opening the lid for maintenance reasons observe following items:
• Do not remove the lid while circuits are live.
• No dust deposits or whirlings are present.
• No rain can enter into the housing.
6.9 Service support
To expedite the return process outside of the United States, contact the nearest Emerson
representative.
Within the United States, call the Emerson Instrument and Valve Response Center using
the 1-800-654-RSMT (7768) toll-free number. This center, available 24 hours a day, will
assist you with any needed information or materials.
The center will ask for product model and serial numbers, and will provide a Return
Material Authorization (RMA) number. The center will also ask for the process material to
which the product was last exposed.
CAUTION
Individuals who handle products exposed to a hazardous substance can avoid injury if they
are informed of and understand the hazard. Returned products must include a copy of the
required Safety Data Sheet (SDS) for each substance.
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Emerson Instrument and Valve Response Center representatives will explain the additional
information and procedures necessary to return goods exposed to hazardous substances.
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Reference Manual Specifications and reference data
00809-0100-4030 March 2022
A Specifications and reference data
A.1 General
A.1.1 Measuring technology
Vibrating fork
A.1.2 Applications
Point level detection in liquid process mediums, including coating liquids, aerated liquids,
and slurries. Suitable for horizontal and vertical installation.
A.2 Physical specifications
A.2.1 Material selection
Emerson provides a variety of Rosemount products with various product options and
configurations including materials of construction that can be expected to perform well in
a wide range of applications. The Rosemount product information presented is intended
as a guide for the purchaser to make an appropriate selection for the application. It is the
purchaser’s sole responsibility to make a careful analysis of all process parameters (such as
all chemical components, temperature, pressure, flow rate, abrasives, contaminants,
etc.), when specifying product, materials, options, and components for the particular
application. Emerson is not in a position to evaluate or guarantee the compatibility of the
process fluid or other process parameters with the product, options, configuration or
materials of construction selected.
A.2.2 Housing/Enclosure
Table A-1: Housing / Enclosure Specifications
Housing code A D X Y S T
Housing material Nylon PA66 30%GF Al alloy ASTM B85
Rotational Yes No No
Paint Not applicable Polyurethane Not applicable
LED window Nylon PA12 None None
316C12 SST
A360.0
Conduit entry M20 ½-in. NPT M20 ¾-in. NPT M20 ¾-in. NPT
Ingress protection IP66/67 to EN60529 IP66/67 to EN60529,
NEMA® 4X
Rosemount 2120 Level Switch 65
IP66/67 to EN60529,
NEMA 4X
Specifications and reference data Reference Manual
March 2022 00809-0100-4030
A.2.3 Process wetted connections
Connections
Threaded, Tri Clamp, and flanged process connection options.
Materials
• 316/316L stainless steel (1.4401/1.4404 dual-certified)
• Alloy C (UNS N10002) and Alloy C-276 (UNS N10276)
Available for flanged, and selected threaded process connections (¾-in. and 1-in. BSPT
(R), and ¾-in., 1-in. and 2-in. NPT).
• ECTFE co-polymer coated 316/316L Stainless Steel (1.4401/1.4404 dual certified)
Available only for flanged process connections, but excludes 1-in./DN25/25A flanges.
• Gasket material for ¾-in. and 1-in. BSPP (G) is non-asbestos BS7531 Grade X carbon
fiber with rubber binder.
Gaskets are not supplied with flanged process connections.
A.2.4 Customer specified fork length
Table A-2: Extended Fork Lengths
Process connection Minimum Maximum
¾-in. threaded 3.8 in. (95 mm) 157.5 in. (4000 mm)
1-in. threaded 3.7 in. (94 mm) 157.5 in. (4000 mm)
2-in. threaded 3.7 in. (94 mm) 157.5 in. (4000 mm)
Flanged 3.5 in. (89 mm) 157.5 in. (4000 mm)
Tri Clamp 4.1 in. (105 mm) 157.5 in. (4000 mm)
(1) The maximum extended length is 157.5 in. (4000 mm), except for ECTFE co-polymer coating and
polished process connection options which have a maximum length of 59.1 in. (1500 mm) and
39.4 in. (1000 mm) respectively.
(1)
A.2.5 Transmissible Spongiform Encephalopathy (TSE)
declaration
This declaration is applicable to Tri Clamp connections, i.e. the 1½-in. (38 mm) and 2-in.
(51 mm) sizes, when ordered with Surface Finish option codes 3, 4, 7 and 8.
Emerson certifies no process wetted components used in this product contain substances
of animal origin. Materials used in the production or processing of wetted components for
this product meet the requirements stated in EMA/410/01 Rev. 3 and ISO 22442-1:2015.
Wetted components in this product are considered free of TSE.
66 Reference Manual
Reference Manual Specifications and reference data
00809-0100-4030 March 2022
A.3 Performance specifications
A.3.1 Hysteresis (water)
0.1 in. (2.5 mm)
A.3.2 Switching point (water)
0.5 in. (13 mm) from fork tip if mounted vertically.
0.5 in. (13 mm) from the fork edge if mounted horizontally.
The switching point varies with different liquid densities.
A.3.3 Liquid density requirements
Minimum liquid density is 37.5 lb/ft3 (600 kg/m3).
A.3.4 Liquid viscosity range
Up to 10000 cP (centiPoise)
A.3.5 Solids content and coating
The maximum recommended diameter of solid particles in the liquid is 0.2 in. (5 mm).
Avoid bridging of forks (fork-to-fork).
A.4 Electrical specifications
A.4.1 Protections
Table A-3: Electrical Protections
Protection Availability on Cassettes
Polarity insensitive Relay (except 12 Vdc version) and Direct Load
Over-current protection Direct Load and PNP/PLC electronics
Short-circuit protection Direct Load and PNP/PLC electronics
Load-missing protection Direct Load and PNP/PLC electronics
electronics
Surge protection (to IEC61326) All electronics
A.4.2 Terminal connection (wire diameter)
Minimum 26 AWG, maximum 14 AWG (0.13 to 2.5 mm2). Note national regulations.
Rosemount 2120 Level Switch 67
Specifications and reference data Reference Manual
March 2022 00809-0100-4030
A.4.3 Conduit plugs/cable glands
Metal housing
Conduit entries for explosion-proof areas are shipped with one Exd plug (loose in bag) and
two dust caps fitted. Use suitably rated cable glands. Unused conduit entries must be
sealed with a suitably rated blanking plug.
Plastic housing
Glass-filled nylon housings with direct load, PNP/PLC and IS electronics are shipped with
one PA66 cable gland and one blanking plug. The cable gland supports cable diameters in
the range 0.2 to 0.3 in. (5 to 8 mm).
Glass-filled nylon housings with relay electronics are shipped with two PA66 cable glands.
The cable gland supports cable diameters in the range 0.2 to 0.3 in. (5 to 8 mm).
A.5 Functional specifications
A.5.1 Switching delay
User-selectable 0.3, 1, 3, 10, 30 seconds delay for dry-to-wet and wet-to-dry switching.
A.5.2 Switching mode
User selectable switching mode (Dry=on or Wet=on).
A.6 Environmental specifications
A.6.1 Maximum operating altitude
6562 ft. (2000 m)
68 Reference Manual
1450 (100)
1160 (80)
32 (0)
-14.5 (-1.0)
-40
(-40)
122
(50)
302
(150)
32
(0)
A
B
Reference Manual Specifications and reference data
00809-0100-4030 March 2022
A.6.2 Maximum operating pressures
Figure A-1: Process Pressure
A. Process pressure, psig (barg)
B. Process temperature, °F (°C)
The final rating depends on the selected process connection.
Threaded connection
See Figure A-1.
Tri Clamp connection
435 psig (30 barg)
Flanged connection
The maximum operating pressure is the lower of the process pressure (Figure A-1) and
flange pressure rating (see Table A-4).
Table A-4: Maximum Flange Pressure Rating
Standard Class/Rating Stainless steel flanges
Mobrey A Not applicable 34 barg
Mobrey G Not applicable 21 barg
ASME B16.5 Class 150 275 psig
ASME B16.5 Class 300 720 psig
ASME B16.5 Class 600 1440 psig
EN1092-1 PN 10/16 16 barg
EN1092-1 PN 25/40 40 barg
EN1092-1 PN 63 63 barg
EN1092-1 PN 100 100 barg
JIS B2220 10K 14 barg
JIS B2220 20K 34 barg
(1)
(1)
(1)
(2)
(2)
(2)
(2)
(3)
(3)
(1) At 100 °F (38 °C), the pressure rating decreases with an increasing process temperature.
Rosemount 2120 Level Switch 69
(2) At 122 °F (50 °C), the pressure rating decreases with an increasing process temperature.
(3) At 248 °F (120 °C), the rating decreases with an increasing process temperature.
176 (80)
122 (50)
32 (0)
-40 (-40)
-40
(-40)
32
(0)
140
(60)
302
(150)
A
B
Specifications and reference data Reference Manual
March 2022 00809-0100-4030
A.6.3 Maximum and minimum operating temperatures
See Figure A-2 for the maximum and minimum operating temperatures.
The ambient temperature for a 8/16 mA cassette is limited to 158 °F (70 °C) in dust
applications.
Figure A-2: Operating Temperature
A. Ambient Temperature, °F (°C)
B. Process Temperature, °F (°C)
70 Reference Manual
BA
C
C
H
H
2.7
(69)
5
(127)
1.7
(44)
4 (102)
3.5 (90)
D
F
G
I
I
4.7 (120)
1.7
(44)
2.7
(69)
5.9
(151)
E
F
G
Reference Manual Specifications and reference data
00809-0100-4030 March 2022
A.7 Dimensional drawings
Refer to the Type 1 Drawings on the Rosemount 2120 web page for dimensions of the 1in. BSPP threaded versions.
Figure A-3: ¾- and 1-in. Threaded Mounting (Standard Length)
A. Glass-filled nylon housing
B. Aluminum/stainless steel housing
C.
Allow 1.2 (30) clearance to remove cover
D. Cable entry M20 x 1.5 or ½-in. NPT
E. Cable entry M20 x 1.5 or ¾-in. NPT
F. 1.6 (40) A/F hexagon
G. ¾- or 1-in. thread
H. 0.5 (13) switchpoint (when mounted vertically)
I. 0.5 (13) switchpoint (when mounted horizontally)
Dimensions are in inches (millimeters).
Rosemount 2120 Level Switch 71
3.5 (90)
A
I
J
J
I
K
5.9
(151)
4 (102)
1.7
(44)
F
G
H
H
D
B
1.7
(44)
4.7 (120)
K
6.7
(171)
F
G
E
C
C
Specifications and reference data Reference Manual
March 2022 00809-0100-4030
Figure A-4: ¾- and 1-in. Threaded Mounting (Extended Length)
A. Glass-filled nylon housing
B. Aluminum/stainless steel housing
C.
Allow 1.2 (30) clearance to remove cover
D. Cable entry M20 x 1.5 or ½-in. NPT
E. Cable entry M20 x 1.5 or ¾-in. NPT
F. 1.6 (40) A/F hexagon
G. ¾- or 1-in. thread
H. Ø1.14 (29) for 1-in. thread; Ø0.9 (23) for ¾-in. thread
I. 0.5 (13) switchpoint (when mounted vertically)
J. 0.5 (13) switchpoint (when mounted horizontally)
K. Customer specified fork length (see Table A-2)
Dimensions are in inches (millimeters).
72 Reference Manual
C
C
A
3.5 (90)
4 (102)
I
J
6.1
(154)
H
H
I
B
Ø1.14 (29)
Ø1.14 (29)
6.9
(175)
J
4.7 (120)
F
G
F
G
D
E
1.7
(44)
1.7
(44)
Reference Manual Specifications and reference data
00809-0100-4030 March 2022
Figure A-5: 2-in. Threaded Mounting (Standard and Extended Length)
A. Glass-filled nylon housing
B. Aluminum/stainless steel housing
Allow 1.2 (30) clearance to remove cover
C.
D. Cable entry M20 x 1.5 or ½-in. NPT
E. Cable entry M20 x 1.5 or ¾-in. NPT
F. 2.6 (65) A/F hexagon
G. 2-in. thread
H. 0.5 (13) switchpoint (when mounted vertically)
I. 0.5 (13) switchpoint (when mounted horizontally)
J. Customer specified fork length (see Table A-2)
Dimensions are in inches (millimeters).
Rosemount 2120 Level Switch 73
A B
5.2
(132)
2.5
(64)
4 (102)
3.5 (90)
D
E
G
F
H
1.7
(44)
6.1
(155)
2.5
(64)
G
F
H
1.7
(44)
4.7 (120)
Ø0.9 (23)
Ø0.9 (23)
C
C
I
I
Specifications and reference data Reference Manual
March 2022 00809-0100-4030
Figure A-6: Tri Clamp Mounting (Standard Length, Surface Finish Codes 1 and 2)
A. Glass-filled nylon housing (and not hygienically approved)
B. Aluminum/stainless steel housing (and not hygienically approved)
Allow 1.2 (30) clearance to remove cover
C.
D. Cable entry M20 x 1.5 or ½-in. NPT
E. Cable entry M20 x 1.5 or ¾-in. NPT
F. 1.6 (40) A/F hexagon
G. 1½-in. (38 mm) or 2-in (51 mm) Tri Clamp
H. 0.5 (13) switchpoint (when mounted vertically)
I. 0.5 (13) switchpoint (when mounted horizontally)
Dimensions are in inches (millimeters).
74 Reference Manual
A B
4 (102)
3.5 (90)
G
H
1.7
(44)
D
Ø1.65 (42)
F
Ø0.9 (23)
5.2
(132)
2.5
(64)
G
1.7
(44)
4.7 (120)
E
F
Ø1.65 (42)
Ø0.9 (23)
2.5
(64)
6.1
(155)
C
C
H
Reference Manual Specifications and reference data
00809-0100-4030 March 2022
Figure A-7: Tri Clamp Mounting (Standard Length, Surface Finish Codes 3, 4, 7, and 8)
A. Glass-filled nylon housing (and hygienically approved)
B. Aluminum/stainless steel housing (and hygienically approved)
C.
Allow 1.2 (30) clearance to remove cover
D. Cable entry M20 x 1.5 or ½-in. NPT
E. Cable entry M20 x 1.5 or ¾-in. NPT
F. 1½-in. (38 mm) or 2-in (51 mm) Tri Clamp
G. 0.5 (13) switchpoint (when mounted vertically)
H. 0.5 (13) switchpoint (when mounted horizontally)
Dimensions are in inches (millimeters).
Rosemount 2120 Level Switch 75
A
D
F
B
E
F
C
C
Ø1.14 (29)
G
H
H
G
4 (102)
3.5 (90)
4.7 (120)
I
5.2
(132)
6.4
(162)
I
1.7
(44)
Ø1.56 (39)
Ø1.56 (39)
Ø1.14 (29)
1.7
(44)
Specifications and reference data Reference Manual
March 2022 00809-0100-4030
Figure A-8: Tri Clamp Mounting (Extended Length, Surface Finish Codes 1 and 2)
A. Glass-filled nylon housing (and not hygienically approved)
B. Aluminum/stainless steel housing (and not hygienically approved)
Allow 1.2 (30) clearance to remove cover
C.
D. Cable entry M20 x 1.5 or ½-in. NPT
E. Cable entry M20 x 1.5 or ¾-in. NPT
F. 1½-in. (38 mm) or 2-in. (51 mm) Tri Clamp
G. 0.5 (13) switchpoint (when mounted vertically)
H. 0.5 (13) switchpoint (when mounted horizontally)
I. Customer specified fork length (see Table A-2)
Dimensions are in inches (millimeters).
76 Reference Manual
A B
Ø1.65 (42)
Ø1.65 (42)
D
F
Ø0.9 (22)
G
G
Ø0.9 (23)
1.7
(44)
E
1.7
(44)
4 (102)
3.5 (90) 4.7 (120)
F
I
I
5.2
(132)
6.1
(155)
C C
H
H
Reference Manual Specifications and reference data
00809-0100-4030 March 2022
Figure A-9: Tri Clamp Mounting (Extended Length, Surface Finish Codes 3, 4, 7, and 8)
A. Glass-filled nylon housing (and hygienically approved)
B. Aluminum/stainless steel housing (and hygienically approved)
C.
Allow 1.2 (30) clearance to remove cover
D. Cable entry M20 x 1.5 or ½-in. NPT
E. Cable entry M20 x 1.5 or ¾-in. NPT
F. 1½-in. (38 mm) or 2-in. (51 mm) Tri Clamp
G. 0.5 (13) switchpoint (when mounted vertically)
H. 0.5 (13) switchpoint (when mounted horizontally)
I. Customer specified fork length (see Table A-2)
Dimensions are in inches (millimeters).
Rosemount 2120 Level Switch 77
A B
3.5 (90)
4 (102)
4.7 (120)
D
F
F
E
G
1.7
(44)
1.7
(44)
4.8
(121)
4
(102)
6
(154)
4
(102)
C
C
G
H
H
Specifications and reference data Reference Manual
March 2022 00809-0100-4030
Figure A-10: Flange Mounting (Standard Length)
A. Glass-filled nylon housing
B. Aluminum/stainless steel housing
C.
Allow 1.2 (30) clearance to remove cover
D. Cable entry M20 x 1.5 or ½-in. NPT
E. Cable entry M20 x 1.5 or ¾-in. NPT
F. Ø0.9 (23) for up to 1 in. flange; Ø1.14 (29) for 1½ in. or larger flange; Ø1.18 (30) for 1½ in. or larger coated
flange
G. 0.5 (13) switchpoint (when mounted vertically)
H. 0.5 (13) switchpoint (when mounted horizontally)
Dimensions are in inches (millimeters).
78 Reference Manual
A B
3.5 (90)
4 (102)
4.7 (120)
1.7
(44)
I
I
4.8
(121)
1.7
(44)
F
G
H
H
F
6
(154)
C
C
G
D
E
Reference Manual Specifications and reference data
00809-0100-4030 March 2022
Figure A-11: Flange Mounting (Extended Length)
A. Glass-filled nylon housing
B. Aluminum/stainless steel housing
C.
Allow 1.2 (30) clearance to remove cover
D. Cable entry M20 x 1.5 or ½-in. NPT
E. Cable entry M20 x 1.5 or ¾-in. NPT
F. Ø0.9 (23) for up to 1 in. flange; Ø1.14 (29) for 1½ in. or larger flange; Ø1.18 (30) for 1½ in. or larger coated
flange
G. 0.5 (13) switchpoint (when mounted vertically)
H. 0.5 (13) switchpoint (when mounted horizontally)
I. Customer specified fork length (see Table A-2)
Dimensions are in inches (millimeters).
Rosemount 2120 Level Switch 79
Ø2.68
(Ø68)
3.62
(92)
3.62 (92)
A
Ø2.68
(Ø68)
Ø5.00
(Ø127)
A
Specifications and reference data Reference Manual
March 2022 00809-0100-4030
Figure A-12: Mobrey ‘A’ Flange
A. 4 off Ø0.55 (Ø14) holes equi-spaced on 3.62 (92) PCD
Dimensions are in inches (millimeters).
Figure A-13: Mobrey ‘G’ Flange
A. 4 off Ø0.55 (Ø14) holes equi-spaced on 3.97 (98.4) PCD
Dimensions are in inches (millimeters).
80 Reference Manual
Reference Manual
00809-0100-4030 March 2022
Rosemount 2120 Level Switch 81
00809-0100-4030
Rev. GA
2022
For more information:
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request. The Emerson logo is a trademark and service mark of
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