APG warrants its products to be free from defects of material and workmanship
and will, without charge, replace or repair any equipment found defective upon
inspection at its factory, provided the equipment has been returned,
transportation prepaid, within 24 months from date of shipment from factory.
THE FOREGOING WARRANTY IS IN LIEU OF AND EXCLUDES ALL OTHER
WARRANTIES NOT EXPRESSLY SET FORTH HEREIN, WHETHER
EXPRESSED OR IMPLIED BY OPERATION OF LAW OR OTHERWISE
INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
No representation or warranty, express or implied, made by any sales
representative, distributor, or other agent or representative of APG which is not
specifically set forth herein shall be binding upon APG. APG shall not be liable
for any incidental or consequential damages, losses or expenses directly or
indirectly arising from the sale, handling, improper application or use of the
goods or from any other cause relating thereto and APG’s liability hereunder, in
any case, is expressly limited to the repair or replacement (at APG’s option) of
goods.
Warranty is specifically at the factory. Any on site service will be provided at
the sole expense of the Purchaser at standard field service rates.
All associated equipment must be protected by properly rated electronic/
electrical protection devices. APG shall not be liable for any damage due to
improper engineering or installation by the purchaser or third parties. Proper
installation, operation and maintenance of the product becomes the
responsibility of the user upon receipt of the product.
Returns and allowances must be authorized by APG in advance. APG will
assign a Return Material Authorization (RMA) number which must appear on
all related papers and the outside of the shipping carton. All returns are subject
to the final review by APG. Returns are subject to restocking charges as
determined by APG’s “Credit Return Policy”.
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The LPU series are loop-powered ultrasonic sensors. The LPU provides a
low-power non-contact level measurement solution. These units are provided
with 4-tactile switches and a 4-digit LCD display to provide the user feedback
in programming and sensor performance data.
Sensor features include:
• Loop powered for low power consumption.
• Built-in keypad and display for easy setup and distance readings.
• Rugged Kynar transducer housing for harsh environments and high degree
of chemical compatibility.
• Microprocessor-controlled.
• Listed by CSA for operation in Class 1 Division 2 Groups C & D and Class
1 Zone 2 A Ex nA IIB hazardous areas.
• NEMA 4X rating for outdoor applications.
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Ultrasonic sensors measure distance
using a transducer to send out
ultrasonic bursts. Each burst contains a
series of 1-20 pulsed sound waves that
emit in the shape of a cone, reflect off
the target, and are received by the
sensor. The time required for the sound
burst to travel to and from the target is
converted into a distance measurement
by the sensor.
Ultrasonic sensing is affected by
several factors including the target
surface, distance, size, and angle. The
following considerations will help
ensure the best possible target
conditions.
Surface
The ideal target surface is hard and smooth and perpendicular to the sensor.
This surface will reflect a greater amount of signal than a soft, sound wave
absorbent surface. A target with poor sound wave reflection characteristics will
reduce the operating distance of the sensor and decrease its accuracy.
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The shorter the distance from the sensor to an object, the stronger the
returning echo will be. Therefore, as the distance increases, the object requires
better reflective characteristics to return a sufficient echo.
Size
A large object will have a greater surface area to reflect the signal than a
small one, therefore, a large target will be detected at a greater distance than a
small target. The surface area recognized as the target is generally the portion
closest to the sensor.
Angle
The inclination of the object's surface facing the ultrasonic sensor affects the
reflectivity of the object. The portion perpendicular to the sensor returns the
echo. If the entire surface is at a great enough angle, the signal will be reflected
away from the sensor and no echo will be detected. Generally a target at an
angle greater than 5 degrees off perpendicular will not be detected.
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DO NOT mount the sensor
where the beam will intersect
objects such as fill streams,
pipes, ladder rungs, wall seams,
or corrugated tank walls.
Installation
The LPU sensor should be mounted so that it has a clear sound path to the
level monitored. Mount the sensor away from tank walls and inlets. The path
should be free from obstructions and as open as possible for the 9° off axis
beam pattern. Follow the guidelines mentioned in "Understanding
Ultrasonics", earlier in this manual. When using a stand pipe to mount the
sensor above the tank, the stand pipe should be seamless and no longer than 4
inches to provide a smooth path for the sound waves to propagate into the
tank. Seams from couplers, nipples or gaskets can cause erroneous echoes and
degrade the sensors performance. The LPU can be mounted in a coupler, or
flange using the 2” NPT threaded case.
Caution: Do not over tighten! The sensor should be threaded in only hand
tight.
The minimum detection range of the LPU is approximately 1 ft. The sensor
should be mounted to ensure the target does not come closer than the
minimum range or erroneous readings may result.
See the Hazardous Mounting section of this manual before mounting the
LPU sensor in a hazardous area.
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The LPU is programmed using modes, similar to a digital wrist watch. The
LPU display and programming buttons can be accessed by loosening the screw
that secures and seals the sensor’s lid. The LCD display shows the distance
measurement. The display is also used to view the individual modes and their
values when programming.
The LPU has four programming buttons, MODE UP, MODE DOWN, VALUE
UP, and VALUE DOWN. The MODE UP/DN buttons allow the user to select
the desired mode while VALUE UP/DN buttons allow the user to view and alter
the settings.
To select a mode, press the MODE UP or MODE DOWN button until the
desired mode is displayed. Press the VALUE UP or VALUE DOWN button once
to view the current setting of that mode.
To change the selected mode setting, press the VALUE UP or VALUE DOWN
button until the desired value is displayed.
To STORE or SAVE the changed mode value, press the MODE UP or MODE
DOWN button once. At this point, the display will show the distance
measurement. The values are stored in a nonvolatile memory, and will not be
lost when power is turned off.
A list of the 17 modes is located on the LPU MODE SHEET near the end of
this manual.
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Zero PointMax. DistanceZero PointMax. Distancemode 11mode 12mode 11mode 12
20 ma
4 ma
4 ma
20 ma
Operation
MODEDESCRIPTIONPARAMETERS
1UnitsRange = 0-2
Default = 0
0 = feet
1 = inches
2 = mm
Mode 1 is used to select the units of measurement that will be used
throughout the setup process and also for display. The units will also
determine the resolution of the display and the outputs. The resolution is: feet
0.01, inches 0.1 and millimeters 1.
NOTE: All modes must be set using the units selected in Mode 1.
MODEDESCRIPTIONPARAMETERS
24 mA distanceUnits = Mode 1
Range = 0-9999
Default = 1.00 ft.
Mode 2 sets the 4 mA distance.
MODEDESCRIPTIONPARAMETERS
320 mA distanceUnits = Mode 1
Range = 0-9999
Default = 25.00 ft.
Mode 3 sets the 20 mA distance.
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Mode 4 is used to select the desired response time. The response time
adjustment is the limit to which the LPU-2127 can keep up with different rates
of change. The response time parameter automatically sets internal filter
parameters for the programmed rate of change. More filter equates to a steadier
output. The most filter is used in setting 1, the least in setting 3.
MODEDESCRIPTIONPARAMETERS
5Fail-safeRange = 0 - 2
Default = 1
0 = hold last
1 = 22 mA
2 = 3.75 mA
Mode 5 sets the output condition that the sensor will revert to in the event of
a loss of echo condition. If this mode is set to 0, the sensor will hold the last
reading until the signal is regained. If set to 1, the output of the sensor will go
to 22 mA If set to 2, the output will go to 3.75 mA.
MODEDESCRIPTIONPARAMETERS
6Fail-safeUnits = Seconds
DelayRange = 5-9999
Default = 15
Mode 6 sets the delay, in seconds, before the output will show a loss of echo
condition. When the LPU does not receive an echo, it will hold the last valid
condition for the number of seconds entered in Mode 5. When this time has
expired, the display and output will change to their fail-safe settings.
Most applications do not require the user to manipulate modes beyond 6.
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Mode 7 fine tunes the minimum current sourced on the analog output.
MODEDESCRIPTIONPARAMETERS
820 mA TrimRange = 0-9999
Default = 5000
Mode 8 fine tunes the maximum current sourced on the analog output.
MODEDESCRIPTIONPARAMETERS
9CalibrationRange = 0-1999
Default = 1000
Mode 9 is used to calibrate the sensor for variations in the speed of sound
due to variations in atmospheres. The default of 1000 is used for most
applications. Assume a decimal after the first digit.
MODEDESCRIPTIONPARAMETERS
10Distance OffsetUnits = Mode 1
Range = -3.00 to 3.00
Default = 0
Mode 10 is used to change the zero point of the sensor.
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Step 1: Point the sensor at a target that is approximately at the
maximum measurement range. Adjust the Mul plier value so
that the sensor distance reading matches the actual measured
distance to the target.
Distance Calibra on
Use a wall or other large ß at target for calibra on at longer ranges.
Step 3: Repeat steps 1 and 2 un l the reading at each endpoint
matches the actual measured distance. The accuracy at both endpoint should improve with each repe on of steps 1 and 2.
measure
measure
Step 2: Point the sensor at a target that is approximately at the
minimum measurement range. Adjust the O! set value so that the
sensor distance reading matches the actual measured distance to
the target.
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0 = OFF
1 = ON
2 = View Temperature (degrees C)/ON
Mode 11 activates or deactivates the internal temperature compensation
circuit. The speed of sound changes with changes in temperature, therefore
changes in temperature can affect distance measurements. These affects can be
minimized by activating temperature compensation. If the mode is exited
while viewing temperature, temperature compensation is turned ON.
MODE DESCRIPTION PARAMETERS
12AutoSenseRange = 0 - 1
Default = 1
0 = Manual (user controls Sensitivity and Pulses)
1 = AutoSense (sensor controls Sensitivity and
Pulses)
Mode 12 activates or deactivates AutoSense. When operating with this
mode active, the LPU-2127 will automatically change the sensitivity and
pulses to match the application. Modes 13 and 15 limit the maximum level
that sensitivity and pulses can be manipulated when operating in AutoSense.
Modes 13 and 15 set the sensitivity and pulses when operating in manual
mode.
MODE DESCRIPTION PARAMETERS
13SensitivityRange = 0 - 100%
Default = 100%
Mode 13 sets the level of gain that is applied to the echo. When operating in
AutoSense, this parameter limits the gain that can be applied to the echo. If
operating in manual, this parameter sets the receive gain. When in manual
mode, set the sensitivity to the minimum value that will allow the target to be
reliably tracked through the full range of environmental conditions.
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Mode 14 sets the blanking distance. The blanking distance is the zone from
the sensor to a point where the first echo will be accepted. Because of the
physical properties of an ultrasonic sensor, objects cannot be detected closer
than approximately 1 foot from the face of the transducer. This distance varies
according to how much energy is being transmitted (Mode 5) and the
installation. Low pulses and soft mounting may allow target detection as close
as 6 inches. The blanking distance can also be used to ignore unwanted targets
close to the sensor such as welds, seams, pipe fittings, or gaskets.
MODE DESCRIPTION PARAMETERS
15PulsesRange = 1-20
Default = 16
Mode 15 sets the maximum number of pulses the sensor can transmit when
operating in AutoSense or simply the number of pulses when operating in
manual (Mode 12). The LPU emits a burst of pulses and measures the time it
takes for the burst to travel to and from the target. The more pulses that are
sent in a burst, the stronger the returning echo. When operating in manual
mode, increase the strength of the transmission by increasing the number of
pulses for detecting soft targets in damping environments. In acoustically
active environments or small enclosed areas, decrease the number of pulses to
decrease the energy transmitted and reduce multiple echoes.
MODE DESCRIPTION
16Software Version
Mode 16 displays the software version of the LPU.
MODE DESCRIPTION
17Reset
Mode 17 resets the LPU to factory default settings
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Note - Jurisdictions in Canada may require these markings to also be provided in French language. It is theresponsibility of the manufacturer to provide bilingual marking, where applicable, in accordance with therequirements of the Provincial Regulatory Authorities. It is the responsibility of the manufacturer to determinethis requirement and have bilingual wording added to the "Markings".
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