Rosemount 2120 User manual

Quick Start Guide
00825-0100-4030, Rev BA
August 2012
Rosemount 2120 Full-featured
Vibrating Fork Liquid Level Switch

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2
Quick Start Guide
NOTICE
This installation guide provides basic guidelines for the Rosemount 2120. It does not provide
instructions for detailed configuration, diagnostics, maintenance, service, troubleshooting,
or installations. Refer to the Rosemount 2120 Reference Manual (Document Number
00809-0100-4030) for more instruction. Manuals are available electronically on
www.rosemount.com.
Failure to follow these installation guidelines could result in death or serious injury
The Rosemount 2120 is a liquid level switch. It must be installed, connected, commissioned,
operated, and maintained by suitably qualified personnel only, observing any national and
local requirements that may apply
Ensure the wiring is suitable for the electrical current and the insulation is suitable for the
voltage, temperature, and environment
Use the equipment only as specified. Failure to do so may impair the protection provided by
the equipment
Any substitution of non-recognized parts may jeopardize safety and is under no
circumstances allowed
Explosions could result in death or serious injury
Installation of the 2120 in a hazardous environment must be in accordance with the
appropriate local, national, and international standards, codes, and practices. Please review
the Product Certifications section for any restrictions associated with a safe installation
Verify that the operating atmosphere of the 2120 is consistent with the appropriate
hazardous locations certifications
External surface may be hot
Care must be taken to avoid possible burns
Process leaks could result in death or serious injury
Install and tighten process connectors before applying pressure
Do not attempt to loosen or remove process connectors while the 2120 is in service
Electrical shock could cause death or serious injury
If the liquid level switch is installed in a high voltage environment and a fault condition or
installation error occurs, high voltage may be present on leads and terminals
Use extreme caution when making contact with the leads and terminals
Make sure that power to the 2120 is off while making connections

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August 2012
Overview of the Rosemount 2120
The Rosemount 2120 is a liquid point level switch. Based on vibrating short fork
technology, the 2120 is suitable for virtually all liquid applications.
The Rosemount 2120 is designed using the principle of a tuning fork. A piezo-electric
crystal oscillates the forks at their natural frequency (~1400 Hz). Changes to this
frequency are continuously monitored. The frequency of the vibrating fork sensor
changes depending on the medium in which it is immersed. The denser the liquid, the
lower the frequency.
When used as a low level alarm, the liquid in the tank or pipe drains down past the fork,
causing a change of natural frequency that is detected by the electronics and switches
the output state to a Dry condition. When the 2120 switch is used as a high level
alarm, the liquid rises in the tank or pipe, making contact with the fork which then
causes the output state to switch to a Wet condition.
The 2120 has a ‘heartbeat’ LED that indicates its operating state. The LED flashes when
the switch output is ‘off’ and is constantly lit when 'on'.
Figure 1. Rosemount 2120 features
A. Visible heartbeat LED G. Wetted material in 316/316L SST, solid
B. Mode switch, adjustable time delay Alloy C and Alloy C-276, or
C. Housings in glass-filled nylon, ECTFE/PFA-coated 316/316L SST
aluminum, or 316 SST H. Short fork length or extensions up to
D. Magnetic test point 157.5-in. (4 m)
E. Threaded, Flanged, or Hygienic Connections I. Two cable/conduit entries
F. ‘Fast drip’ fork design J. Direct Load, Relay DPCO, PLC/PNP,
NAMUR, or 8/16 mA electronics
F
B
A
G
H
C
I
J
E
D

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Quick Start Guide
General considerations
Handle the Rosemount 2120 with great care. Use both hands when carrying the
extended length versions. Do not hold the 2120 using the forks
Do not alter the 2120 in any way
Figure 2. How to handle the Rosemount 2120
The 2120 is available as intrinsically safe or explosion-proof/flameproof versions
for hazardous area installations (see page 16 for approvals)
There are ordinary location versions of the 2120 for unclassified, safe areas
This liquid level switch is designed for open or closed tanks, and pipe installation. It
is weatherproof and protected against the ingress of dust, but must be protected
from flooding (Figure 3)
The 2120 operates in process temperatures of –40 to 302 °F (–40 to 150 °C)
Figure 3. Environmental considerations
Ensure there is adequate space outside the tank or pipe. A clearance of 1.2 in.
(30 mm) is required for the cover to be removed
Always ensure a proper seal by installing the electronics metal housing cover so
that metal contacts metal, or plastic contacts plastic. Use Rosemount O-rings
Always ground the housing in accordance with national and local electrical codes.
The most effective grounding method is a direct connection to earth (ground)
with minimal impedance. Use the fork earth for metal housings with NPT conduit
entries
OK OK
OKOK

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August 2012
Installation recommendations
Avoid installing near liquid entering the tank at the fill point
Avoid heavy splashing on the forks.
Increasing the time delay reduces accidental switching
Avoid installing near heat sources
Ensure the fork does not come into contact with the tank/pipe wall, or fittings
Allow a sufficient distance between product build-up on the tank wall and fork
Figure 4. Avoid product build-up around the forks
Step 1: Physical installation
1. Install the 2120 according to standard installation practices, making sure to
correctly align the fork using the alignment notch or groove (Figure 6).
2. Use supports for extended fork lengths greater than 3.2 ft. (1 m) (Figure 5).
For the GL approval requirements, see reference manual 00809-0100-4030.
3. Close the housing cover and tighten to safety specification. Always ensure a proper
seal so that metal touches metal or plastic touches plastic, but do not over tighten.
4. Insulate the 2120 with Rockwool. See Figure 7 for clearances.
Figure 5. Supports needed for an extended fork (standard)
OK
3.2ft.
(1 m)
3.2 ft.
(1 m)
3.2 ft.
(1 m)
3.2ft.
(1 m)
Max. 3.2 ft. (1 m)
Max.
3.2 ft.
(1 m)

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Quick Start Guide
Figure 6. Example installations
A. PTFE for NPT and BSPT (R) Thread
B. Gasket for BSPP (G) Thread
C. Fork Alignment Groove
D. Fork Alignment Notch
E. Fork Alignment Notch
A
E
C
B
D
Threaded 2120
installation
Flanged 2120
installation
D

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August 2012
Figure 7. Insulation
A. 3.9 in. (100 mm) Clearance All Around
B. 5.9 in. (150 mm)
C. Rockwool
AA
B
C

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Quick Start Guide
Step 2: Electrical installation
Before use, check that suitable cable glands and blanking plugs are fitted and
fully tightened.
Isolate supply before connecting the switch or removing the electronics.
The functional earth terminal must be connected to an external
earthing system.
Direct load switching electronics cassette (two-wire, red label)
High level Dry = ON Low level Wet = ON
LED on continuously LED flashes each
second LED on continuously LED flashes each
second
Direct Load
Switching
WARNING
Isolate Supply
Before Removing
OPERATION MODE
Dry On Mode
Dry
Wet
Wet On Mode
Dry
Wet
Dry On Wet On
Seconds Delay
0.3 0.3
3
30
10
1
3
30
10
1
123
LINE
LOAD
PE
(Ground)
Neutral Live
0V
Fuse 2A(T)
R
I
L
R = External load (must be fitted)
U = 20 - 264V ~(ac) (50/60Hz)
I
OFF
< 4 mA
I
L
= 20 - 500 mA
U = 20 - 60V (dc
)
)
I
OFF
< 4 mA
IL = 20 - 500 mA
DPST
+V
= 5 A, 40 ms (inrush)
I PK
= 5 A, 40 ms (inrush)
I PK
= Load On
= Load Off
Note: The values
shown are nominal;
see the 2120
Reference Manual
00809-0100-4030
for complete data
Dry On Wet On
Seconds Delay
0.3 0.3
3
30
10
1
3
30
10
1
Dry On Wet On
Seconds Delay
0.3 0.3
30
10 3
30
10
1
3
1
U
N L
0V +V
Fuse
2A(T)
I
L
12V
DPST
Fuse
2A(T)
N L
0V +V
IL
<4mA
DPST
U
N L
0V +V
Fuse
2A(T)
IL12V
DPST
Fuse
2A(T)
N L
0V +V
IL
<4mA
DPST

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August 2012
PNP/PLC electronics cassette (three-wire, yellow label)
High level Dry = ON Low level Wet = ON
PLC (positive input)PNP dc
LED on
continuously
LED flashes each
second LED on
continuously LED flashes each
second
OPERATION MODE
Dry On Mode
Dry
Wet
Wet On Mode
Dry
Wet
Dry On Wet On
Seconds Delay
0.3 0.3
3
30
10
1
3
30
10
1
123
OUT
+-
4
PLC/PNP
Isolate Supply
Before Removing
PE
(Ground)
0VO/P
U = 20- 60 V (dc)
I < 4 mA + I
L
I
L ( MAX )= 0 -500 mA
U
OUT(ON)
= U - 2.5 V
I
L(OFF)
< 100A
+V
Fuse 2A(T)
= 5 A, 40 ms (inrush)
I PK
Note: The values
shown are nominal;
see the 2120
Reference Manual
00809-0100-4030
for complete data
Dry On Wet On
Seconds Delay
0.3 0.3
3
30
10
1
3
30
10
1
Dry On Wet On
Seconds Delay
0.3 0.3
30
10 3
30
10
1
3
1
OUT
-
+
PLC
+
I/P
U
<3V I
L
OUT
-
+
PLC
+
I/P
I
L
<100 A
OUT
-
+
PLC
+
I/P
U
<3V I
L
OUT
-
+
PLC
+
I/P
I
L
<100 A
OUT
-
+
+
U
<3V
I
L
Fuse
1A(T)
R
OUT
-
+
+
I
L
Fuse
1A(T)
R
< 100 A
OUT
-
+
+
U
<3V
I
L
Fuse
1A(T)
R
OUT
-
+
+
I
L
Fuse
1A(T)
R
< 100 A

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Quick Start Guide
Relay output electronics cassette (DPCO, green label)
High level Dry = ON Low level Wet = ON
LED on continuously LED flashes each
second LED on continuously LED flashes each
second
NC CNO NC NO
789
NOCNC
RELAY
123
LN
456
NOCNC
OPERATION MODE
Dry On
Dry
Wet
Wet On
Dry
Wet
Dry On Wet On
Seconds Delay
30
10
3
1
0.3 0.3
30
10
3
1
Isolate Supply Before RemovingWarning
C
Resistive Load
cos φ= 1 ;
L/R = 0 ms
ac
dc
Inductive Load
Fuse 0.5 (T)PE
(Ground)
DPST
N
0V +V
Live U = 20...264 V ~ (ac)
(50/60 Hz)
U = 20...60 V (dc)
I < 6 mA
I < 6 mA
IMAX = 5 A
UMAX = 250 V
PMAX = 1250 VA
UMAX = 30 V
PMAX = 240 W
cos φ= 0.4 ;
L/R = 7 ms
ac
dc
IMAX = 3.5 A
UMAX = 250 V
PMAX = 875 VA
UMAX = 30 V
PMAX = 170W
Dry On Wet On
Seconds Delay
0.3 0.3
3
30
10
1
3
30
10
1
Dry On Wet On
Seconds Delay
0.3 0.3
30
10 3
30
10
1
3
1
NC NOCNC NOC
NC NOC
NC NOC
NC NOCNC NOCNC NOC
NC NOC