Babbitt Liquid User Manual

BABBITT LG SERIES

LIQUID LEVEL GAGES

INSTRUCTION MANUAL

Babbitt International, Inc. 713-467-4438
P.O. Box 70094 Fax [phone]

Houston, TX 77270 www.babbittlevel.com

Detailed Description

The LG Series Level Gage consists of a glass (or polycarbonate) indicator and float chamber,
which is mounted directly to the process vessel. Standard gages are normally flanged or coupled
to the process vessel, but a variety of mounting styles are available to suit most any vessel or
piping requirements. (See Table 1 of the brochure for more details.)

Gages are manufactured to meet the exact specifications of the process such as operating
pressure, temperature, specific gravity, etc. Standard materials are stainlesssteel,howevermost
any non-magnetic material may be used including PVC, Kynar, Hastelloy, Monel, Alloy 20, and
many others. A magnetized float is contained inside the chamber, which is designed to meet the

requirements of the process conditions. (For this reason, floats are not interchangeable unless
process conditions are identical.) The float moves freely inside the gage chamber as level rises
and falls. Under normal conditions, the float should be about 70% submergedin the process fluid,
but it is important to note that the position of the float in the fluid will vary with different process
conditions.

STANDARD INDICATION

The scale assembly used for indicating level consists of the clear indicator tube with the red
magnetic follower or “bird” and a graduated scale marked with feet and inches (special scales are

available, ie: metric, gallons, 0-100%, etc.) The scale is mounted parallel and immediately next to
the indicator tube. The tube is hermetically sealed to prevent moisture and dirt accumulation. A
rubber “bumper” is sealed inside the bottom of the tube to cushion the impact of the “bird” against
the glass. The bright red bird provides maximum visibility (even at night), however light kits for

illuminating gages are available. A black reference line around the bird allows the operator to
match the graduated scale with the actual level of the process fluid. Positive zero indication is
provided by a nameplate at the lower end of the scale. If the bird is de-coupled from the float, the
bird will fall down behindthis nameplate andwill not be visible. Thus,whenthevesselisempty,the
level gage will read zero and the bird is still visible float. To prevent the float from losing magnetic

coupling with the bird, a spring or stop plate is mounted into the top and bottom of the gage
chamber. This cushions the impact of the float against the chamber when the process vessel is
completely full or empty.

FLIPPER/ROLLER INDICATION (OPTIONAL)

Babbitt offers a flipper/roller style indicator as an option to the standard tube/follower indicator.
“Flippers” are industrial grade indicators, which consist of a series of metal flags,silver on one side
and red on the other. As the magnetic float moves up and down with the level, each flagwill rotate

180° to show the other color. Babbitt flippers are housed in a rugged, hermetically sealed
aluminum housing with a recessed glass window. Each flag rotates on a ceramic and stainless
steel bearing surface, whicheliminates “sticking”or hanging up. Flipper assemblies arebuilttothe
length of the level gage in one continuous piece up to 20 feet with no joints or blind spots.

FLIPPER/ROLLER INDICATION (OPTIONAL) (Cont.)

Flipper assemblies are offered as an option to the standard Babbitt indicator where surging or
turbulent levels may cause “de-coupling” problems. They are also more highly visible than the
standard indicator. They come with or without the scale in feet and inches.

INSTALLATION

LG Series gages are securely packed in specially designed crates to provide maximum protection
of the glass tube and float chamber during shipment. It is important to unpack and inspect each

gage upon receipt to insure the glass tube and chamber are free from damage. If you should find
bent or broken parts, contact Babbitt immediately. All Babbitt gages are fully insured against
damage or loss (unless otherwise specified by customer), however claims must be filed within 15
days from date of receipt of shipment.

The float chamber should always be leveled vertically. If it is not leveled vertically, the float may
become magneticallyuncoupled from thebird. Should this happenduringinstallation,simplyusea
permanent magnet or magnet tool (available from Babbitt) to pull the bird back up to the float’s
magnetic field. See the TROUBLESHOOTING section of this manual for more details on
re-coupling float and birds.

Valves should be installed between the process vessel and level gage to allow draining, cleaning,
etc. Standard blockvalves may be used and canbe ordered with the gagefromBabbittorsupplied
by the customer. All gages are shipped complete with 0.125 inch composition gaskets.

NOTE: IF COMPOSITION GASKETS ARE NOT COMPATIBLE WITH YOUR PROCESS
CONDITIONS, APPROPRIATEGASKETSSHOULD BE USED IN PLACE OF THOSE SHIPPED
WITH THE GAGE.

PRESSURE TESTING

All Babbitt gages are hydrostatically test to 1.5 time the specified pressure rating prior to shipment
to insure pressure tolerance. However, the gage should be blocked in or the float removed if the

process vessel is to be pressure tested in the field by the customer as most vessels are tested at
much higher pressures thanthe maximum operatingprocess pressure. While the float chamber is
capable of withstanding these higher pressures, the float is not and may collapse under vessel
tests. Should floats be damaged during testing, replacements are supplied at the customer’s

expense.

FLANGES & CONNECTIONS

Process connections and vent/drain flanges are designed to meeteach customer’s specifications.
The graduated scale assembly is based on the length of the float chamber from center to center of
the process connections. All flange boltholes straddle the centerlines unless otherwise specified.
On STYLE A Level Gages “stop plates” are supplied to insure the float is contained inside the
chamber. For more information on dimensions, flanges, etc., see Tables 1-3 in the brochure.

IMPORTANT!!!! IF YOU DON’T READ ANY OTHER PART OF THIS
MANUAL, PLEASE READ THIS PAGE. IT MAY SAVE YOU TIME, MONEY
AND MUCH FRUSTRATION.

PLACING THE GAGE IN SERVICE

To insure proper operation of the level gage, the following steps should be taken:

1. Make sure that operatingconditions (temperature,pressure,specificgravity,etc.)are
within maximum rating of the gage. Each gage has a permanent nameplate at the
bottom of the scale indicating process specifications, serial number, tagnumber etc.

2. Install float. The float is marked “TOP” to insure proper orientation.

2a. On STYLE E Level Gages (Top Mount) remove float stop.
2b. STYLE A Level Gages are supplied with floats stops which should be installed between top

and bottom process connections.

3. The float chamber should be closed withno openings to the atmosphere. Check to see that
all drain and vent plugs are securely in place and any vent and drain valves are closed.

IMPORTANTNOTE: THIS STEP IS VERY IMPORTANTIN HIGH PRESSURE APPLICATIONS.
IF THE BOTTOM VALVE IS OPENED FIRST AND THE VESSEL IS UNDER PRESSURE, THE
FLOAT INSIDE THE CHAMBER WILL SHOOT UP LIKE A “CANNONBALL” AND COULD
LODGE IN THE TOP OF THE CHAMBER CAUSING SEVERE DAMAGE TO THE FLOAT AND
CHAMBER.

4. When the gage is mounted and ready to be put into service, the TOP process
connection valve should be opened first and should be opened slowly to allow any
pressure to equalize. This allows process fluid or vapor to enter the gage slowly and
reach operating pressure and temperature at a reasonable rate.

5. When the gage has reached process process pressure, then open the bottom

process connection and installation should be complete.

CAUTION: NEVER USE THE VENT OR DRAINON THE GAGE AS A PRESSURE RELIEF FOR
THE PROCESS. DOING SO MAY PERMANENTLY DAMAGE GAGE AS WELL AS CAUSING
HAZARD TO PERSONNEL.

REMOVING THE GAGE FROM SERVICE

To remove the gage from service, the following steps should be followed carefully:

1. Close the BOTTOM process connection vale to prevent further filling of the gage.
Then close the TOP process connectionvalvetocompletelyisolatethegagefromthe

process pressure.

2. Attach proper vapor collection equipment to the gage vent connection if required.
Open the top vent to relieve pressure in the gage and allow air to flow when the

bottom drain is opened.

3. Attach the proper liquid collection equipment to the bottom drain and remove liquid. After

all process fluid is out of the gage, the gage is then ready to be removed from service.

ROUTINE MAINTENANCE

Standard Babbitt gages have 1/2 inch vent and drain plug in the top and bottom of the float
chamber to allow cleaning and removal of the process fluid as required. Some gages are

connected by the customer to a solvent or steam line which allows them to decontaminated or
“blown down” periodically without taking the gage out of service or removing the drain flange and
float. Babbitt gages should be cleaned and inspected at least on an annual basis, or more
frequently depending on the severity of the process. To perform maintenance and clean gage,
follow these procedures:

1. Block in the float and chamber with the process connection valves or wait until the
vessel is empty or out of service. Follow the steps on previous page for “Removing
The Gage From Service”.

2. When all thefluid has been drained from thegage chamber, remove the drain flange
and let the float slide out of the chamber. Be sure to examine the float for excessive
wear and clean as required.

3. Clean the inside wall of the chamber with a “bottle brush” or similar scrubbing tool.
Some processes may dictate the use of suitable solvent for cleaning.

4. If the gage is located when the bottom drain is near the floor or other equipment
where it is difficult to reach, it is possible to order gages with a top flange in place of
the standard vent plug, or the drain flange may be mounted to the top instead of the

bottom. This allows the gage to be cleaned and serviced through the top end.

5. After cleaning the chamber, replace the float and drain flange. A new flange gasket
may be required. (Note: Make sure to use gaskets compatible with the process fluid
if replaced.)

ROUTINE MAINTENANCE (cont.)

6. Check the stainless steel pipe clamps to insure they are tight and adjust the scale
holder up or down on the float chamber to make sure the positive zero is correctly
positioned.

7. Use a permanent magnet ora magnet tool from Babbitt to attract thered “bird”until it
is again coupled to the float inside the chamber.

LG SERIES PARTS LIST

When ordering replacement parts for Babbitt Gages, the following information is required:
a. Serial number of gage or accessory item

b. Description of item
c. Original purchase order if possible

A. TYPICAL FLOAT CHAMBER PARTS

1. Vent plug and spring

2. Drain flange and spring

3. Drain plug

4. Magnetized float

5. Top float spring

6. (Style A Only) Float stop plates with spring

B. INDICATOR SCALE ASSEMBLY

1. Scale/Channel Assembly

2. Indicator Tube (glass or polycarbonate)

3. Pipe Clamps

4. Name Plate

5. Indicator tube mounting blocks (top and bottom)

C. FLIPPER/ROLLER OPTION

TERMS & CONDITIONS OF SALE

1. All orders should be entered as follows:
Babbitt International, Inc.

P. O. Box 70094
Houston, TX 77270

TERMS & CONDITIONS OF SALE

2. TERMS: Net 30 days to approved customers (representatives assume collection
responsibility for new accounts at their discretion). Late charges willbe added at the
rate of 1.5% per month.

3. All shipments will be FOB warehouse (Houston, TX.) Via motor freight, insured.
Freight charges will be collected, or prepaid if specified.

4. Because each gage is designed to customer specifications, there will be no re­stocking option after shipment is made. Cancellation charges after order placement
willbe at the discretionof Babbitt anddependentupon production phaseof thegage.

5. Warranty is outlined in this manual supplied with the gage and does not cover glass
breakage or any other liability other than materials and workmanship.

6. Anyspecial terms and conditions not detailed hereshouldbesubmittedinwritingand
approved by an authorized representative of Babbitt International, Inc.

WARRANTY

AllBabbitt products are warranted againstdefects in materialsand workmanship for one year from
date of shipment. The level gage chamber and process connections are guaranteed for the life of
the tank or vessel to whichit is attached. Floats are guaranteed for two years. Babbitt willrepair or
replace at it’s discretion those products which fail to perform as specified, with the following

exceptions:

1. Products repaired or modified by person that are not authorized by Babbitt.

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 anyother 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. Defectiveproducts shallbe returned to the factoryprepaidbythebuyer
after obtaining a Return Authorization Number from Babbitt.

Anymodificationsto termsand conditions of this warrantywillnot bebindingunlessmadeinwriting
and signed by an authorized agent or official of Babbitt.

NOTE: ALL BABBITT GAGES SHOULD 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 SHOULDBE SUBMITTED WITHIN 15 DAYSOF RECEIPT OF GOODSBY
CUSTOMER.

MLS-3, MLS-3EX LEVEL SWITCHES

DESCRIPTION

The MLS-3and MLS-3EX are electrically the same, the EX version comes with an explosion proof
housing with terminal block. The MLS-3 switch is a hermetically sealed Bi-Stable latching reed

switch with SPDT Form C contacts. The switch is actuated by the float and latches, thus
maintaining the contact after the float continues to rise or fall with level. The MLS-3 is best suited
for low power alarm signals.

SPECIFICATIONS

Deadband: .50 Inches
Max. Temperature: 650°F – HT Version

350°F – STD Version

Min. Temperature: -40°F
Contacts: Form C SPDT
Maximum Ratings:

Switching Voltage: 150 Volts AC/DC
Current: 1.0 Amps AC/DC

Power: 25 Watts DC/VA

SWITCH OPERATION/MOUNTING

To mount the MLS Series Level Switch simply clamp it directly to the side of the level gage
chamber using the adjustable pipe clamps provided. Alarm set points may be changed by simply
loosening the clamps and sliding the switch to the desired alarm level. To set up desired starting

state follow the steps below:

WIRING DETAILS

RISING LEVEL ALARM

MLS-3 Yellow Green Red Green
MLS-3EX A(NC) C B(NO) C

FALLING LEVEL ALARM

MLS-3 Red Green Yellow Green
MLS-3EX B(NC) C A(NO) C

SWITCH OPERATION/MOUNTING (cont.)

The wire leads on the MLS-3 should beterminatedusingsuitablemeans(wirenuts,Terminalblock,
etc.) The MLS-3EX are provided with a terminal block inside the explosion proof enclosure.

Afterthe switches are mounted and wired, they need to be set to the desired state for rising
or falling level as noted previously. This is easilyaccomplished by either manually pushing
the float or magnet past the highest switch, or filling the gage chamber with fluid until all
switches are properly set.

Note: Refer to Appendix B for pump up/pump down instructions.

MLS-9EX LEVEL SWITCH

The MLS-9EX is an explosion-proof hermetically sealed mercury tilt switch. This switch is
designed to switch higher voltages and currents. It is a SPDT switch with “break-before-make”

action. As the float passes, the switch changes state with a rocking action caused by a rod
magnet, which latches it in place. The contacts are maintained until the float passes again in
the opposite direction.

SPECIFICATION

Deadband: .50 Inch
Max. Temperature: 650°F – HT Version

350°F – Standard Version
Min. Temperature: -30°F
Contacts: SPDT

MAX RATINGS:

Switching Voltage: 230 Volts AC/DC
Current AC/DC: 10 Amps
Switching Power: 1250 Watts

MOUNTING

The MLS-9EX are simply mounted to the level gage chamber using stainless steel band clamps.
The switch must be originated properly,switch is marked “TOP”.Itisadjustablethefulllengthofthe

level chamber. To set up desired contact state follow the steps below:

RISING LEVEL ALARM

Common (NC) (NO)
TERMINAL 2 3 1
FALLING LEVEL ALARM

Common (NC) (NO)

TERMINAL 2 1 3

After the switch is mounted and wired, it needs to be set to the desired state for rising or falling
level as noted above. This is easily accomplished by either manually pushing the float past the

highest switch or filling the gage chamber with fluid until all switches are properly set.

Note: Refer to Appendix B for pump up/pump down instructions.

MLS-10EX LEVEL SWITCH

The 10-EX level switch is a DPDT high current device used to control pumps, alarms, solenoids,
etc. The 10-EX is a cam-activated switch designed for use with the LG series magnetic level
gages. The switch can be factory set for either a rising or falling condition depending upon the
specific application. The 10-EX meets all Class 1, Div. 1 codes and the internal switches are

UL/CUL listed. For more information on specific applications contact the Babbitt Engineering
department at [phone].

ELECTRICAL SPECIFICATIONS

10 AMP Max. @ 125/250 VAC
½ AMP Max. @ 125 VDC

3.0 AMP Max. @ 30 VDC Resistive

2.0 AMP Max. @ 30 VDC Inductive
Contact Configuration: DPDT

ENVIRONMENTAL CONDITIONS

Max. Temperature: +200°F HT Version: +450°F
Min. Temperature: - 65°F

HOUSING

Explosion Proof cast aluminum condulet.

FLIPPER/ROLLER RETROFIT

INSTALLATION & START-UP

When flipper indicators are purchased with a Babbitt gage no installation is necessary.
However, if the indicator is removed or a retrofit kit is purchased for a gage already in service,
the following should be noted:

1. The mounting clamps connecting the flipper assembly to gage chamber, are adjustable to

most manufacturers’ standard (i.e.: 1 ½” to 2 ½” pipe).

2. If the gage is in service and there is liquid in the tank, only the individual flippersadjacent to

the float will rotate to red when the indicator assembly is clamped on.

3. To reset indicator to show true level, the operator can

a. Run a magnet along window of indicator from 0 to where red is showing as noted in

item 2.

OR

b. Drain gage to empty to zero the indicator, then fill again and as float rises with the

level indicator will then be set and read properly

(red = liquid, silver = vapor space).

TROUBLESHOOTING BABBITT LEVEL GAGES

Babbitt gages are a relatively simple to install and use. The following troubleshooting tips may be
of help during installation and startup but reading the entire manual helps even more.

1. “Float magnetically de-couples from red indicator “bird”.

(Note: if bird is de-coupled, it will fall behind nameplate and will not be visible.)
If this is a recurring problem, it could be caused by several things, most of them resulting

from improper installation of the gage.

a. Check to make sure that scale and channel assemble are tight against the gage chamber

the entire length of the scale so that magnetic coupling is maintained from top to bottom of

the indicator tube. Sometimes, especially with longer gages over 5-6 feet, the glass will bow
out slightly and the float will lose coupling with the bird at some point. Stainless steel tie-wires

are supplied with gages over 5 feet long to keep the glass from bowing out. Make sure these
tie-wires are in place, tightened and secure.

b. Check to make sure the float inside the chamber is right side up. If the float has been placed

in the chamber upsidedown, ithas onlyhalf normal magnetic strengthand willde-couplefrom

the indicator bird. All floats are clearly marked “TOP”.

c. Iffloat-stop springs or plates mounted in the top and bottom of the gage chamber have been

removed, the float will continue to rise past the top of the indicator tube and will lose coupling

with the bird at that point.

d. Sudden violent surges of process fluid could cause de-coupling. If this isacommonproblem,

de-coupling may be minimized by partially closing the process connection valves (or retrofit

gage with flipper/roller option).

e. If the center-to-center dimension has been miscalculated and the gageisslightlytoolong,don

not force it into place as this may cause the chamber to bow slightly and the float will not be

able to pass freely through the entire length of chamber. This will also cause de-coupling.

If none of the above tips applies to your de-coupling problem, contact Babbitt for more information
or for replacement floats and/or indicators. Also note that magnets exposed to extreme
temperatures (over 1100°) will lose their magnetic properties. Other problems that could damage
float causingde-coupling problems include over pressurization, solids or largeparticulatelodgedin
the chambers or even dropping the float.

2. “Babbitt gage’s level differs from true level in the tank.”

This is a fairly common problem during start-up and is easily corrected. Under normal
conditions, mostfloats are about70% submergedintheprocessfluids(magnetsareinupper
portion of the float). It is important to note that the position of the float in the fluid will vary
with different process conditions. To get a true reading, simply loosen the pipe clamps that
mount the indicator scale and tube andadjust the scale up or down the chamber as required

to get exact reading (within ½ inch).

TROUBLESHOOTING (cont.)

3. “Indicator tube is cracked or broken.”

If the glass indicator tube is cracked or broken replacement can be shipped usually within
24 hours after ordered. One of the advantages of the Babbitt gage is the glass is easily
replaced without taking the gage out of service or shutting down the process. To replace
the glass, loosen the two screws in the PVC or Teflon block located in the top or bottom
of the scale assembly, remove the block and slide out the broken glass. If the gage is

over 6 feet tall, it may be easier to remove the entire scale and channel by loosening the
pipe clamps and taking it off the gage. This will protect the glass when replacing it and
remounting it to the gage chamber.

4. “Level switches don’t trip properly.”

All level switches may be wires to trip on rising or falling level. After the switch is wired for
the desired action (see instructions in this manual), it is necessary to set the switch. This
is easily accomplished by passing the float either manually or by filling the gage chamber

till it passes the highest switch. This will trip the switch to the desired setting so it will
alarm properly with rise or fall of level.

PS-2 PNEUMATIC SWITCH

DESCRIPTION

The PS-2 is a pneumatic switch designed to control air and natural gas from 15 to 100 psi. The
PS-2 is rotary cam activated and incorporates a non-bleed switch. When the float passes, the
cam rotates and latches the switch in the open position. This will allow unobstructed airflow.
When the float moves back in the opposite direction the switch unlatches and blocks the airflow.

The non-bleed design of the PS-2 makes it ideal for controlling applications requiring natural
gas. The PS-2 can also be used to control pneumatic alarms, pumps and valves. Refer to
interconnect diagram for connections and mounting instructions.

PS-2 SPECIFICATIONS

Deadband 0.7 inch
Max. Temperature 300°F
Min. Temperature 0°F
Supply Pressure @ 70°F 15 -100 psi

Supply Pressure @ 300°F 15 - 35 psi

(Dry, Filtered air or gas)

Housing 316SS, Nema 4

PS-2H SPECIFICATIONS

Deadband 0.7 inch
Max. Temperature 450°F
Min. Temperature 0°F
Supply Pressure @ 70°F 15 - 100 psi
Supply Pressure @ 450°F 15 - 60 psi

(Dry, Filtered air or gas)

Housing 316SS, Nema 4

Note: Refer to Appendix A for further details.

LT-1/LT-2 2-WIRE TRANSMITTER

DESCRIPTION

The LT-1 Level Transmitter is designed for use with the LG Series Level gage to provide a
4-20mA control signal proportional to level. The transmitter consists of a sensor tube made up
of a string of resistors and magnetically operated reed switches. There is a switch and resistor
every ½ inch or ¼ inch along the length of the sensor tube.

The circuit board containing the resistors and switches may be the same length as the
measured range or any portion thereof. The sensor circuit in enclosed in the stainless steel
sensor tube. A threaded connection at the top of the tube is for mounting the transmitter
housing. This housing is rated for Class 1, Division 1, Groups C & D hazardous areas. The LT-1
assembly may be made intrinsically safe by remote mounting of the transmitter in a safe area

and operating the sensor through an approved safety barrier.
As the magnetic float inside the gage chamber rises with increasing fluid level, the switches

close, thereby changing the resistance in the circuit. A two-wire transmitter converts this
resistance change to a 4-20mA current signal corresponding to fluid level. Resolution of the

transmitter is ½ inch (proportional to the spacing of the sensor switches).

SPECIFICATIONS

SENSOR TRANSMITTER

Length Up to 20 Feet Output 4-20mA
Resolution ½ inch LT1-4/20-L-1/2 Power 24 VDC Nominal

¼ inch LT1-4/20-L-1/4 Load 750 Max
Housing 304 Stainless Steel
Operating Temp. to 500°F (Process Fluid)

LT1 CALIBRATION AND TROUBLESHOOTING

USING FLOAT IN LEVEL CHAMBER

A quick check of the calibration is accomplished (with gage mounted) by draining the level
chamber, checking the mechanical zero and then adjusting the sensor tube up or down until it

reads 4mA. Refill the gage chamber or fill it to a point that corresponds to the top range of the
transmitter. The output should now read 20mA.

If a complete calibration is to be performed, remove the transmitter and sensor tube from the
level gage and follow the steps below:

1. Normal operation/Dip Switch 1,2,3 OFF 4 ON

2. Place magnet (float) at 0% (or 4mA mark) on sensor tube.

3. Adjust P2 to Read 4mA on 24 VDC current Loop

USING FLOAT IN LEVEL CHAMBER (cont.)

4. Place magnet (float) at 100% (or 20mA mark) on sensor tube. Adjust P3 to read 20mA

on 24 VDC current Loop.

5. Repeat Steps 3 and 4 if necessary until transmitter is reading 4mA to 20mA.

6. Check 50% (12mA mark).
Clamp the sensor back on the gage chamber loosely and slightly higher than it should be.

Make sure the float in the chamber is in the zero position. Slowly adjust the sensor tube
downward until the output goes to 4mA. Tighten the clamps and the transmitter is calibrated. If
there is a question about the output, compare it to the visual indication on the gage. One can
also place a magnet against the sensor tube at a point above the gage float and the transmitter
should give an output corresponding to that point, i.e.: if the gage is indicating 2 feet and a

magnet is placed against the sensor at the 4 foot level then the output of the transmitter should
jump to indicate 4 feet.

CALIBRATION SWITCHES

The LT-1 is equipped with an onboard calibration circuit that is factory set to simulate a level
represented by a current loop output. The calibration switches can be set to produce a 4mA,
12mA and a 20mA output. The proper settings for the switches are displayed on page 20 and in

figure 1-0. The LT-1 calibration circuit was designed for simple adjustments of the zero and
span without having to shut down the process. It should be noted that the calibration switches
bank of four DIP switches are adjusted to produce the appropriate current output based upon
the length of the LT-1 sensor tubes, and are therefore not interchangeable with sensor tube of
different lengths.

CALIBRATION USING A VOLTMETER

Figure 1-0 shows a standard setup using a series resistor (250 ohms) to measure a voltage
range of 1 to 5 volts. Connect a voltmeter in parallel with the 250-ohm resistor. Set the
calibration switches to the 4mA position and adjust P2 on the LT-1 circuit board until a reading
of volt is displayed on the voltmeter. To adjust the span set the calibration switches to the 20mA

position and adjust P3 until a reading of 5 volts is displayed on the voltmeter. To verify that the
midpoint is accurate and linear, place the calibration switches in the 12mA position. The
voltmeter should now display 3 volts.

CALIBRATION USING AN AMMETER

Figure 1-1 shows a typical set up for measuring the output of a transmitter within the current
loop. This particular procedure does not require the use of a resistor. Connect an ammeter in

series with the power supply and the LT-1 transmitter. Set the range on the ammeter to read a
level of 20mA maximum. Set the calibration switches to the 4mA position and adjust P2 on the
LT-1 circuit board until a reading of 4mA is displayed on the ammeter. Set the calibration
switches to the 20mA position and adjust P3 until a reading of 20mA is displayed on the
ammeter. Verify the midpoint by setting the calibration switches to the 12mA position. The

ammeter should display 12mA.

MULTIPLE TRANSMITTER

For multiple transmitter setup using single power supply make sure you have a 24 VDC
regulated power supply and refer to figure 1.2 for wiring.

WIRING

Term 1+ 24 VDC Positive
Term 3- 24 VDC Negative

Term 4 Sensor
Term 5 Sensor

SENSOR CHECK/DIP SWITCH LOCATION

OFF ON

Normal Condition 1 2 3 4

0%(4mA) 2 1 4 3

50%(12mA) 1 3 4 2

100%(20mA) 3 2 4 1