BABBITT LTM Series Installation instructions manual

LTM – Series
Models: LTM-
250 and LTM
Magnetostrictive
Level Transmitters
Operation
5155 April Lane
Houston, Texas 77092
Phone: [phone]
Fax: [phone]
E-mail: [e-mail]
250 and LTM
-350
Level Transmitters
Instructions &
Operation
Manual
Instructions &
Manual
LTM-350_IOM Rev.3 08/09

Table of Contents
Section 1: Warranty .......................................................................................................................................1
1.0 Warranty.......................................................................................................................................................... 1
Section 2: Transmitter Overview ...................................................................................................................2
2.0 General Description......................................................................................................................................... 2
2.1 Product Identification...................................................................................................................................... 2
2.2 Transmitter Configurations ............................................................................................................................. 2
2.3 Gage Mounted Transmitter............................................................................................................................. 3
2.4 Standalone Transmitter................................................................................................................................... 3
Section 3: Transmitter Description .................................................................................................................5
3.0 Detailed Description......................................................................................................................................... 5
3.1 Technology-Theory of Operation ..................................................................................................................... 5
Section 4: Installation.....................................................................................................................................7
4.0 Gage Mount Installation................................................................................................................................... 7
4.1 Standalone Installation..................................................................................................................................... 7
4.2 General Installation Guidelines ........................................................................................................................ 7
4.3 Insulation (against extreme heat/cold).......................................................................................................... 10
Section 5: Field Wiring..................................................................................................................................11
5.0 Recommended Loop Wiring........................................................................................................................... 11
5.1 Area Classification Installation Safety ............................................................................................................ 13
Section 6: Transmitter Specifications ...........................................................................................................14
6.0 Hazardous Locations/General Ratings ........................................................................................................... 14
6.1 Electrical Specifications .................................................................................................................................. 14
6.2 Sensor Probe Specifications ........................................................................................................................... 14
Section 7: Menu Structure and Features ......................................................................................................15
7.0 Pushbutton Operation................................................................................................................................... 15
7.1 Menu Structure ............................................................................................................................................. 16
7.2 Features (also exclusive features for models: LTM-250/350)....................................................................... 21

Table of Contents
Section 8: Transmitter Calibration and Troubleshooting................................................................................25
8.0 Calibration ..................................................................................................................................................... 25
8.1 Troubleshooting ............................................................................................................................................ 25
8.2 Power Supply Troubleshooting ..................................................................................................................... 26
8.3 General Troubleshooting............................................................................................................................... 26
Section 9: LTM-350 has HART Protocol .........................................................................................................27
9.0 HART Protocol: General Information ............................................................................................................ 27
9.1 Process Variables........................................................................................................................................... 27
9.2 HART Info....................................................................................................................................................... 28
9.3 Device Setup.................................................................................................................................................. 30
9.4 Calibration Review......................................................................................................................................... 43
9.5 Advanced Setup............................................................................................................................................. 45
9.4 Device Diagnostics......................................................................................................................................... 46
Icon Key
Warning/Caution Valuable Operation Information
Important Information to Know
Read Carefully these Tips are the “DON’Ts” of the instrument.

Section
1Warranty
1.0 Warranty
in materials and workmanship for a period of no
less than one year from the date of shipment. The
level gage chamber and process connections are
guaranteed for the life of the tank or vessel to
which it is attached. Floats are guaranteed for two
discretion those products that fail to perform as
specified, with the following exceptions:
1. Products repaired or modified by persons
2. Products subjected to misuse, negligence or
accidents.
3. Products that are connected, installed, or
otherwise used in such a way not in strict
accordance with manufacturer’s
instructions.
This warranty is in lieu of any other warranty
expressed or implied by any party other than
Babbitt. Repairs and/or replacements shall be at
the sole discretion of Babbitt based on the terms
and conditions of this warranty. Defective products
shall be returned to the factory prepaid by the
buyer after obtaining a Return Authorization
Number from Babbitt. All warranty repairs or
replacements will be performed at the factory in
Houston. Factory warranties do not include field
service. Field service warranty repairs will be at the
buyer’s expense.
Any modifications to terms and condition of this
warranty will not be binding unless made in writing
and signed by an authorized agent or official of
be unpacked and thoroughly inspected upon
receipt. Gages are shipped FOB factory and
are fully protected against damage or loss
during shipment. Any claims for parts
damaged during shipment should be
submitted within 15 days of receipt of goods
by customer.
We value your opinion and want to better
serve you. Please go our website:
www.babbittinternational.com and click the
customer feedback survey option (on the left
side of the screen). Some of the best
suggestions for improvement come from our
valued customers. Let us know how we are
doing and what we can do better to improve
your satisfaction with our product and service.
1
All Babbitt products are warranted against defects
years. Babbitt will repair or replace at its
All Babbitt gages and transmitters should
that are not authorized by Babbitt.
Babbitt.

Section
2Transmitter Overview
2.0 General Description
The LTM-Series are electronic field instruments,
suitable for installation in hazardous and non-
hazardous locations. Testing and certification has
been obtained from different agencies for
installation in such areas. This instrument is
designed to measure and transmit an analog and/or
digital signal proportional to liquid level in a tank.
The complete assembly includes a dual
compartment explosion-proof enclosure and
attached sensor tube and a magnetic float. The
LTM-Series are available in a variety of lengths and
wetted materials to accommodate many different
applications.
2.1 Product Identification
Figure 1. Example label/name plate
The product can be identified by the stainless steel
label that is located on the side of the transmitter
enclosure/housing.
The label can be read as follows:
wwww = Any hazardous location area classification
markings that the instrument is approved for.
ZZ/ZZ = Born on date; the2 digit month and 2 digit
year the instrument was shipped to the customer.
AAAA = The specific serial number assigned by
Magtech for complete traceability.
BBBB = The overall probe length of the instrument.
Note: THIS IS NOT THE MEASURING RANGE.
XXXX = The measuring range of the instrument.
The 0 and 100% (4/20mA) output range.
YYYY = The end user specified tag number (only
when specified).
2.2 Transmitter Configurations
LTM-Series transmitters generally have two
configurations:
1. Gage Mounted: Where the transmitter is
mounted on the outside of a magnetic level
gage and strategically located within a
certain longitudinal distance from the
transmitter sensor probe and a magnetic
float is placed inside the level gage.
2. Standalone (or Direction Insertion Type):
Where the transmitter has a magnetic float
directly around the transmitter sensor
probe and the probe is directly inserted into
a tank/vessel.
In either configuration as the tank level changes,
the float tracks the change and continuously
activates the sensor probe. The electronics process
the change in signal and output an analog and/or
digital signal. This output is precisely the liquid level
in the tank.
unique applications that require their own
distinctive configurations. Please consult the
factory for guidance.
2
wwwwwwwwwwwwwwwwwwwww
ww
ZZ/ZZ S/N AAAA / OL BBBB
MODEL LTM- 350-G-XXXX
TAG YYYY
wwwwwwwwwwwwwwwwwwwwwww
wwwwwwwwwwwwwwwwwwwwwww
Babbitt is always willing to explore

2.3 Gage Mounted Transmitter
The LTM-Series may be strapped to the outside of
an installation, it is used as an accessory transmitter
for the visual level gage. The same float used to
activate the magnetic gage is also used to activate
the magnetostrictive sensor of the LTM and
transmit a directly proportional 4/20mA signal.
The depiction below shows the gage mount
installation of the LTM-Series to a mag-gage. The
transmitters may be calibrated for the same range
as the visual indicator on the mag-gage, or for part
of the range depending on the application.
Figure 2. Gage mounted transmitter
conjunction with other manufacturers’
magnetic level gages. Full warranties will apply
upon factory approval. Float replacement may
be required.
2.4 Standalone Transmitter
When a magnetic level gage is not present, the LTM
float mounted around the sensor tube.
The depictions below show the standalone version
of the LTM-Series with various process connections
and the standard float stop with centering ring.
Figure 3. Transmitters with various process connections.
In Figure 3:
Transmitter A depicts a standard ¾” compression
fitting that is on all standalone transmitters.
Transmitter B depicts a ¾” compression fitting and
a hex plug. This option is highly recommended
because the hex plug is selected based on the
float’s diameter (OD), so if the instrument ever
needs to be removed or serviced for any reason it
can be removed by the hex plug.
Transmitter C depicts a flanged option with a ¾”
compression fitting and a hex plug.
3
the Babbitt LG series magnetic level gage. In such can be inserted into the tank/vessel with its own
Babbitt transmitters may also be used in

A stilling well may be used along with the
transmitter inside the tank. Stilling-well is a pipe
external to the sensor probe and float encasing the
entire assembly protecting it from surface agitation
or from physical damage due to the length of the
sensor probe. A depiction of a transmitter with a
stilling well is provided below.
Figure 4. Transmitter with a Stilling-well
When a stilling well is used, care should be
exercised when installing the tube to center it in
the chamber so that the float can freely travel
the entire length of the probe. Stilling wells are
required for transmitters over 10 feet or the
instrument cannot be considered under
warranty.
Optional Features that are available with the
LTM-350 but NOT the LTM-250 are:
1. HART Protocol, which enables:
a. A second digital output proportional to
an interface level (requires a second
float of different specific gravity)
b. A digital temperature output that
reflects the liquid temperature.
c. Advanced diagnostics and features
highly beneficial for commissioning,
troubleshooting or monitoring.
Up to two floats may be used with the LTM-350
only. The second float will typically sense the
interface level (the heavier of the two fluids) in the
tank. The specific gravity of the second float will be
such that it can be totally immersed in the lighter
fluid. The drawing below shows a transmitter with
dual floats, one for total level and the other for
interface level (also available with various process
connections).
Figure 5. Dual Output Transmitter
A dual output transmitter is also available
in a gage mount configuration. Consult factory
for further details.
4

Section
3Transmitter Description
3.0 Detailed Description
The LTM-Series is an assembly of two major
components:
The Sensor Tube Assembly: This is a 5/8” diameter
stainless steel probe, sealed on one end, with the
magnetostrictive waveguide in its center. In
addition to the magnetostrictive waveguide, the
tube also houses the optional temperature sensor
and the sensing elements. The tube is made to
lengths of 2-30ft. in rigid construction.
The Enclosure and Electronics: The extruded
aluminum housing has two compartments. The
enclosure is rated NEMA 4X and 7. One side
contains the microprocessor board assembly and
calibration push buttons. The other side contains
the field wiring termination board. The electronics
module is connected to the detector board of the
sensor tube assembly via a plug-in cable. The
electronics module houses printed circuit boards
(PCB) that encompass surface mount component
construction utilizing the latest integrated circuit
technology.
that can be utilized. Please contact factory for
further details.
3.1 Technology – Theory of Operation
The LTM-250/350 series level transmitters are
based on the principle of magnetostriction, first
used for digital delay lines and later precision
distance or displacement in the machine tool
industry. This principle, if designed and applied
properly, has potentially very high measurement
resolution, typically better than 0.001 inch. In the
machine tool industry such a high resolution is
desirable. In the level measurement application,
however, a resolution of 0.01 inch is more than
adequate.
In a brief description, the magnetostrictive principle
consists of a wire extruded and heat treated under
carefully chosen conditions to retain desired
magnetic properties, which is pulsed by a circuit
with a relatively high current pulse. The high
current pulse produces a circular magnetic field as it
travels down the wire at the speed of sound.
Another magnetic field generated by a permanent
magnet (the float), placed near or around the wire
at some distance from the point of entry of this
pulse interferes with the magnetic field of the
current pulse and a torsional force results at the
collision point.
Figure 6. Principle of Operation
The effect of this torsion force is a twist to the wire
at this point producing torsion wave traveling
towards both ends of the wire. The propagation
time (or time-of-flight) of this wave is measured
precisely and if the wire properties remain stable, it
is very repeatable at about 5-10 microseconds per
inch, which is approximately the speed of sound in
that medium. By measuring the exact number of
microseconds it took the torsion wave to reach a
designated termination point of the wire, the
distance to the magnet from this termination point
can be easily calculated.
5
Babbitt also has a stainless steel enclosure

A high-speed microcontroller is utilized in the
design to process and calculate the elapsed time
measurement. Accurate crystals are used for the
time based to resolve sub-microsecond timing
increments. The binary number, equivalent to the
microseconds of the echo travel time is used to
calculate the distance of the float and a
corresponding digital signal is output. A basic block
diagram describing the operation is shown below.
Figure 7. Basic Transmitter Block Diagram
Calibration routines are included in the software to
the 0% and 100% points for any distance desired.
Even reverse calibration is a simple task using the
software routines. Reverse calibration is desirable if
ullage instead of level is required, or when the
probe is installed with bottom mount head.
The LTM-350 transmitter has four output
configurations.
Configuration options must be chosen at
quoting stage.
1. Primary Level – The most basic version of this
transmitter is that it computes the distance
between the float and the detector from the
elapsed time measurement. A specific
interrogation pulse is applied to the waveguide.
Any feedback signal received before and after
this window is rejected as noise. Even signals
received during the active window are
evaluated and filtered so that only high integrity
data is accepted. The conditioned signal is
converted to a percent of full-scale number and
a number representing the distance and output
as a digital signal. (LTM-250/350)
LTM-350, via HART protocol only.
2. Primary Level and Interface Level – A second
float may be added below the first, and the
second output will be calibrated automatically.
The second time interval is timed in the same
manner as the first one and added to the first to
derive the position of the heavier float. The two
floats require a separation of approximately
three inches. The float size, geometry, and
magnetic strength all play a factor in how close
the two floats can be without interfering with
each other.
3. Primary Level and Temperature – An optional
temperature sensor is embedded inside the
bottom tip of the probe, and it is configured to
be the third digital output of the transmitter,
and comes factory calibrated for the operating
range of -50C to 149C (-58F to 300F)
4. Primary Level, Interface Level, and
Temperature –This options is called a ‘full-
blown” unit and offers all three possible
outputs.
A deadband of approximately two inches,
next to the detector, is fixed in the software
and the float is not permitted to enter this
area. If this happens output readings maybe
erratic or go to fail mode.
6

Section
4Installation
4.0 Gage Mount Installation
The LTM-Series can be mounted to the side of a
brackets and stainless steel hose clamps. When
mounting the transmitter to an LG series gage the
active sensor region of the probe should fall within
the centerline of the process connections on the
gage. If the transmitter’s deadband region is inside
the centerline of the process connections the
transmitter will not output an accurate
measurement because the active region of the
probe is too short. When placing an order for a
transmitter to accompany an existing gage it is
important to indicate the style of the gage, the
temperature, and the center-to-center dimension.
Calibration of the probe is factory set to the
center-to-center dimensions provided; however a
re-ranging may have to be performed to match the
probe to the desired control room specifications.
See Section 7.1 “Change Range” for more details.
4.1 Standalone Installation
The LTM-Series standalone transmitter comes
equipped with a ¾” mnpt compression fitting,
mounted approximately 6.00” below the electronics
housing. The fitting is placed in this area to ensure
the transmitter is calibrated in the sensor tubes
active region. Refer to the standalone drawings for
a visual description of the transmitter features.
Optional configurations are available upon request
(2” mnpt, flanges, etc…). The magnetic float used in
the stand-alone unit is designed to travel up the
sensor tube with the change in fluid level. If build-
up of process or contaminates should restrict the
movement of the float, the transmitter sensor tube
will have to be cleaned or the float may have to be
replaced with one that has a larger inside diameter.
The floats are designed to match the pressure and
specific gravity for the process being measured and
come in various materials ranging from stainless to
kynar. The magnetic float can be changed out at any
time to accommodate the processes being
measured. The float stop, located at the bottom of
the transmitters, can be removed to allow the float
to slide off the sensor tube.
4.2 General Installation Guidelines
The basic steps to installing the LTMs are:
1. Inspection of equipment: Inspect the parts
that are listed on the packing slip. Make sure
nothing appears to be damaged such as a
broken glass from the level indicator assembly
(flippers), damaged float, or a damaged
transmitter. Please file a claim with the
shipping company immediately if it is believed
the shipment has arrived damaged and be
prepared to provide pictures.
The sensor probe of the transmitter
SHOULD NOT BE BENT, BOWED, OR KINKED in
any way or the transmitter will not work (will
most likely go into fail mode).
The following is a depiction of damaged probes:
Figure 8. All damaged sensor probes
7
Babbitt LG series level gage using special mounting