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Engine
Dynamics Measurement
Engine dynamic measurements
can be made to less than one micron and up to 1000°F,
50Khz using our non contact eddy sensors. For more information
on the Kaman range see the Kaman
page.
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Use Of Precision Non-Contacting
Proximity Measuring Sensors In Tri-Axial Soil Test Rigs.
PURPOSE:
The purpose of these rigs is to determine the mechanical properties
of soil samples under test.
Various customers, with interests in the geophysical properties
of sub-soils, rocks, etc. in differing industries have such
rigs. The knowledge of the stability of sub-soils and rocks,
etc. is critical for road and rail track foundations, tunnelling,
mining, oil industry, civil engineering, etc.
METHOD:
The core samples of various materials such as clay, sand, rocks,
chalk, bitumen, etc., usually about 2" to 4" in diameter
and with an ideal length of about 2 x diameter are placed in
the rig, immersed in a fluid such as silicon oil or water and
pressurised to represent the soil depth of the sample. The samples
are often encased in a latex membrane which functions to hold
the sample together, isolate it from the fluid and to hold the
sensor target in place. On some samples, such as rock, the membrane
may be omitted and aluminium targets be bonded directly to the
sample.
The proximity sensors are arranged in the rig to precisely measure
the deformation of the sample in 3 planes. Dynamic or static
loads are applied to the sample from as electromagnetically
driven ram.
Kaman non-contacting sensors with a measuring range of 2 mm
are typical for the application, supplied with hermetically
sealed bulhead connectors in the sensor leads and sealed against
any ingress of water if required.
Signal processing electronics are available in various packages
with options of analogue voltage outputs with frequency response
from static to 50 kHz, or digital outputs via RS-232C and RS-485
serial ports.
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Sensors For Sub-Sea Operation
A requirement to measure the movement of a sub-sea structure
in the North Sea was met using KAMAN SMU-9000-3"PC sensors
with integral electronics.
The units had to be proofed against sea-water to 100 metres
depth. This was achieved by potting the 3" diameter sensor
coil and integral electronics into a 4" diameter PVC tube.
The assembly was then encapsulated in a polyurethane moulding,
after calibration, together with a mounting stud and cable assembly.
Underwater mateable connectors were fitted to the cables to
allow the sensors to be installed by divers.
After assembly, the units were tested to 120 metres of sea-water.
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Pressure Dead Weight Tester,
Weight Float Height Measurement.
Deadweight pressure testers are widely used as primary and working
pressure standards throughout industries where being assured
of the accuracy of a pressure measurement is a criteria.
Deadweight testers comprise of a precision piston and cylinder
assembly, plus a set of calibrated masses. They operate be applying
a given force over a known cross sectional area of a piston
with a matched cylinder. The cylinder is filled with the pressure
medium, (Usually oil or gas), and the seepage of the medium
past the piston provides the lubricant, keeping the piston free
from the cylinder wall and virtually friction free. With this
technology, it is possible to obtain and measure pressures to
a very high level of accuracy.
The height at which the piston floats within the cylinder can
be critical to the accuracy of the measurement, as can the sink
rate of the piston as the pressure medium on which it is floating
gradually seeps past it.
For many pressure measurement operations, (such as differential
pressure calibrations, or when carrying out a cross-float calibration
of one Deadweight tester against another), it is necessary to
float two weight sets simultaneously. The Kaman EASI/EURO-9500
dual channel systems, (with the right sensor selection), is
the ideal instrument to make the weight float height measurements
throughout the calibration process.
Depending upon the type and make of the deadweight tester, the
sensors can be set up to either look at the bottom of the lower
weight on the carrier, or from above, to look at the top of
the weight stack. The-45U or 15U1 are the preferred choice of
sensor for most deadweight tester types.
Kaman's PC-EASI and E-CHART software packages
are ideal for this application. The "Quick Display"
provides an easily understood representation of the piston heights,
and the "E-CHART" displays the sink rate information.
Alternatively, the user can generate his own tailor made software
package which could incorporate any other calibration routine
data and information. For a simpler installation, the analogue
outputs from each channel can be displayed on a pair of suitably
scaled edge meters.
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Using Position Sensing to
Control Roll Gap
PROBLEM: Roll gap consistency
A mill uses two huge calendar rollers (up to 3 feet in diameter
by about 10 feet long) to calendar a web material (paper, tissue
paper, rubber, neoprene, wood pulp, drywall, etc.) and also
to perforate and texture it. For example, one roller may be
plated with an embossing pattern; the other with a deboss pattern.
As the web is passed between them, the pattern is transferred
to the web material.
The manufacturer wants to obtain - on-line - precise information
on the movement of the rollers and the gap between them (+0.1
mil). The operator wants this position data initially for set
up. This information is then used to adjust the position of
the rollers and the gap between them for SPC, and for process
control as the web is calendered.
Knowing the precise roller gap is critical for several reasons.
Too much roller pressure could tear or cut the web or cause
web jams. Too little pressure could affect pattern or perforation
quality, or cause out-of-tolerance thickness deviation. Equally
important is roller cost. Huge calendar rollers are expensive,
and engaging them too far could cause damage or excessive wear.
SOLUTION: On-Line Measurement
Kaman Instrumentation has developed special sensors that measure
the gap between the rollers as the web is running.
Two Kaman sensors (sensor type is dictated by roll gap distance
and environmental considerations) are mounted on bearing blocks,
one at each end of the top roller (see Figure 1). A conductive
target (300 stainless, aluminium or steel) 0.020 to 0.050-inches
thick is mounted on the opposite bearing block.
To determine roller gap, the sensor measures the position of
the target in relation to itself. When the operator knows the
distance between the sensor and the target, he then knows the
position of the bearing blocks and can calculate roller gap.
The data also indicates if either roller is tilted. Kaman's
sensors are, in effect, making a direct measurement of the roller
gap.
The Benefits of Inductive Sensors
Kaman's sensors use inductive technology that measures target
position without touching the tar-get. These systems are unaffected
by environmental contaminants such as paper dust and dirt which
can collect around the sensor during operation. Nor are they
affected by the water used to wash the rollers.
Using the Signal
Kaman's system can provide an analog signal proportional to
the roller gap, which can be directly input to a Kaman signal
conditioner or function module. Limits (rollers too close, rollers
too far apart, wad detection, or other conditions) can be preprogrammed
to notify the operator of an out-of-tolerance situation, providing
complete on-line control of the calendering.
In this application, the output from the sensors is generally
processed by signal conditioning electronics housed in a NEMA-12
enclosure, which is also immune to the environment. The NEMA42
box holds two channels, one function card, and a power supply
and can support two optional integral displays, one for each
channel. Output can be sent to a PLC or other computer via RS-232
or RS-485 links.
Kaman's digital signal processing offers enhanced process control
through the use of user-defined calibration tables, maths functions
operating on user-selected input parameters (such as roll gap),
and the setpoint triggering options described above. The result
is reduced costs and improved quality.
Temperature Compensation
The temperature in a process environment may shift significantly
between start-up and run conditions. Kaman's digital signal
conditioning electronics compensate for temperature error, producing
more accurate readings.
Custom Solutions
In addition to standard products, we offer custom-designed systems
to meet the performance, packaging, and price requirements for
OEMs. We'll work with you to develop a system for your application.
Measuring Web Thickness On-Line
The processor of a non-conductive fibre web must regulate material
thickness (+0.001 inch) across its width and length. Web thickness
is controlled by the position of two drying rollers. Two solutions
are possible.
The first solution is to mount the sensor so it measures the
shaft or bearing block position (see diagram above). Note that
if proper centring of one roller relative to the other is important,
two sensors can be mounted at each end of the roller to monitor
position of the roller shaft in both X and Y directions.
The second solution is a contact measurement via a single-channel
sensor mounted to a shoe that slides across the web as it exits
the rollers. The sensor looks through the non-conductive web
to a metal backing (see diagram above). This solution is equally
effective for particle board and plastics.
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Precision Sensing in
Plastics Injection Moulding
PROBLEM: Wall Thickness
A plastics injection or transfer moulder needs to ensure that
the thickness of a product is to-specification (e.g. +0.1 mil).
The manufacturer uses a two-piece mould with the mould core
cantilevered off the lid which is secured before the plastic
is injected. Since the plastic is injected into the cavity at
one point at a high pressure, it may put unequal pressure on
the sides of the mould cavity, causing cavity deformation. This
results in non-uniform wall thickness and excess flash (waste).
The manufacturer wants to obtain information on the movement
of the mould core as the plastic is being injected. They will
use this information to adjust parameters affecting core movement
(i.e. melt temperature, pressure, and core / mould temperature)
and for SPC monitoring.
Uniform wall thickness is critical for several reasons. The
manufacturer may be required to meet a minimum thickness tolerance
for strength, safety, or other critical factors. Also, the moulder
wants to minimize the plastic used to keep material costs down
without jeopardizing specifications.
Using a micrometer to measure wall thickness of the moulded
object after it is ejected is not typically desirable since
many products are moulded before the defect can be discovered.
It is also time consuming to measure complex shapes in this
manner.
SOLUTION: On-Line Measurement
Kaman has developed a special sensor that measures the thickness
of the plastic as it is being moulded. It can also measure the
gap between the mould and core during set-up to ensure proper
position.
Kaman's sensor is embedded and sealed into the outer mould (see
Figure 1). The face of the sensor is typically flush with the
inside wall of the outer mould, so that little or no marking
occurs on the product being moulded. The sensor is usually positioned
toward the bottom of the mould, where the core is least supported
and, thus, most dimension-ally unstable.
To determine thickness, the sensor measures the gap between
the mould and the core for comparison with a specification to
obtain optimum plastic thickness.
The Benefits of Inductive Sensors
Kaman's inductive sensors can look through the gap between the
core and mould and through the plastic (non-conductive) to determine
the position of the copper or iron inner core (conductive).
Kaman's inductive technology is unaffected by the presence of
plastic. Nor is it affected by the colour of the plastic or
the dielectric differences between air and plastic, unlike laser
or capacitive technologies.
Kaman's sensors operate accurately in the extreme heat and pressure
of the moulding process. Even though the sensor is installed
in a cooled environment (the mould), it can withstand temperatures
exceeding 400°F and pressure up to 20,000 psi.
Using the Measuring System Signal
Measuring system output can be used in numerous ways to provide
on-line process control or satisfy quality control requirements.
The system can provide an analog signal proportional to the
parameter being measured, which can be input directly to a Kaman
signal conditioner or function module. One common function is
the triggering of set-points to warn of out-of-tolerance conditions,
indicating the need for process adjustment or shutdown.
Kaman's system also supports signal input to a PLC or computing
device via analog, RS-232, or RS-485 communication links. This
provides a convenient method to achieve data collection for
SPC on mould system set-up or process improvement.
Kaman's digital signal processing offers enhanced process control
through the use of user-defined calibration tables, maths functions
operating on user-selected input parameters (including mould
gap, part thickness, mould temperature), and the set-point triggering
options described above. This results in process cost reduction
and improved part quality.
Temperature Compensation
The temperature of a moulding environment will shift significantly
between start-up and run conditions. Kaman's digital signal
conditioning electronics compensate for temperature error, producing
more accurate readings.
Using Kaman Sensors To Measure Clamshell Mould Separation
An injection moulder needs to monitor the separation between
two halves of a clamshell-type mould to ensure proper mould
or part dimensions. Again, shape tolerances for strength, safety,
or consistency may be critical factors.
Kaman's sensors can provide an analog signal proportional to
the separation, trigger a set-point when an out-of-tolerance
condition is reached, or both. The sensor can be used in both
open and closed loop systems. In this application, the sensor
is mounted on the out-side of the clamshell mould to monitor
the separation (see Figure 2). For larger moulds, more than
one sensor can be used to measure separation at several points
along the seam.
Real-time monitoring of the moulding process offers an increased
measure of control. The use of excess material may be drastically
reduced. Shipment of out-of-tolerance products is avoided. Downtime
is minimized. Maintenance can be conducted on an as-needed rather
than scheduled basis.
CUSTOM SOLUTIONS Kaman Instrumentation draws on over
30 years of experience with inductive, non-contact position
measurement techniques to bring you the best in advanced sensor
technology and signal conditioning electronics. We'll work with
you to develop a system for your particular application. Besides
standard products, we offer custom-designed systems to meet
the performance, packaging, and price requirements for OEMs.
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Precision Grinding
Objective
- Controlling the position of a high precision servo grinder.
- Maintaining the position of the grinding wheel to within
a few micro-inches to meet the finished part tolerances.
- Making measurements in the presence of environmental
contaminants, such as machining oil.
Solution
Kaman's SMU-9000-6U1 measuring system
How does the system work? The sensor is mounted above the grinder
(see Figure 1) and monitors the radial position of the rotary
drive shaft. A bipolar analog output indicates the position
of the grinding wheel relative to the ground part. The signal
from the sensor directly controls the position of the grinder
through a closed-loop feedback circuit. Result: Precise grinding
of parts for improved component life.
The Kaman Advantage
Why use the SMU-9000-6U1 measuring system?
- noncontact. Using eddy current technology, the
sensor can measure position without ever touching the target.
The result is an extremely reliable system with no moving
parts.
- high sensitivity. The system's sensitivity of
4 micro-inch/mV allows for precise control of the grinding
wheel's position.
- custom design. A microseal treatment protects
the sensor face from machining oil and splashing coolant.
The SMU-9000-6U1 also incorporates an integral sensor cable,
eliminating the need for an electrical sensor-to-cable connection
that can be degraded by environmental contaminants.
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Mirror Steering
Objective
- Positioning steering mirrors to control and track laser
beams used for communication and research.
- Maintaining accuracy in the sub-microradian range while
positioning the mirror, so that a reflected laser beam will
find its target hundreds of kilometres away.
Solution
Kaman's KD-5100 measuring system
How does the system work? Four inductive sensors - one pair
per axis-are mounted behind the mirror to detect its position
throughout its range of motion (see Figure 1). Each sensor acts
as one leg of a balanced bridge circuit; when the mirror pivots,
the bridge becomes unbalanced. The sensors provide a bipolar
output voltage proportional to the angular displacement of the
mirror.
Result: Mirror position is measured with extremely fine resolution.
The Kaman Advantage
Why use the Kaman KD-5100 measuring system?
- noncontact. Using eddy current technology, the
sensor can measure position without ever touching the target.
The result is an extremely reliable system with no moving
parts.
- high resolution. The mirror's position is measured
with accuracy in the sub-microradian range, limited only
by the sensor's fixing.
- flexibility. Multiple sensor configurations are
available to accommodate a variety of measuring ranges and
other performance considerations, such as mirror size and
displacement.
- compact packaging. The KD-5100 is small (2.12
x 2.00 x 0.75 in.) and lightweight (2.5 oz.).
- versatility. The KD-5100 system can be used to
position steering mirrors in applications ranging from communication
satellites to night vision systems to laser optics.
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Semiconductor Wafer
Positioning (Chemical Vapour Deposition)
Objective
- Applying uniform films onto silicon wafers by chemical
vapour deposition (CVD).
- Ensuring uniform deposition of the chemical layer on
the wafer.
Solution
The Kaman SMU-9000 measuring system
How does the system work? Before deposition begins, Kaman's
sensors ensure that the plate holding the wafer is parallel
to the showerheads that disperse the process gases (see Figure
1). The sensors are used for calibration to verify that the
plate's position is within limits. Kaman's system provides an
analogue output or an optional digital interface to signal out-of-tolerance
conditions. If the plate is tilted, an actuator levels it.
Result: Consistent and uniform deposition quality.
The Kaman Advantage
Why use the Kaman SMU-9000 measuring system?
- direct measurement. A sensor ring attached to
a spring-loaded floating plate allows direct measurement
of the position of the showerhead.
- noncontact. Using proven eddy current technology,
each sensor can measure the position of the target without
ever touching it.
- high resolution. The system can sense position
change to one nanometer.
- system versatility. The system is available with a wide
range of sensor options.
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Liquid Density Measurement
using Ultrasonic Sound
PROBLEM.
A UK manufacturer of dampening circulators for printing machines,
needed to measure the specific gravity of mixtures of water
and alcohol very accurately.
It's products control the composition of the solutions used
to prevent the dots in the printed sheets from spreading.
On-line measurement of the specific gravity is generally considered
quite difficult. Techniques based on vibrating rods and similar
methods are strongly affected by liquid viscosity as well as
density. |
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SOLUTION.
The manufacturer uses a float that sits at a depth in the solution,
dictated by the specific gravity of the liquid. Its exact position
is measured by using a Migatron model RPS-401A-40 ultrasonic
displacement transducer. The float is 150mm long and 100mm wide
and sits in a tube. Its upper surface is attached to a rod and
disc attachment. The ultrasonic transducer is placed 140mm above
and bounces its sound waves off the disc. The arrangement determines
the float position to an accuracy of 0.5mm.
The temperature of the liquid must also be measured. After applying
the necessary corrections and calculations, alcohol content
can be determined to an accuracy of 1%.
APPLICATIONS.
In the printing machine system, composition of water and alcohol
mixture is controlled by opening a solenoid valve to admit more
alcohol if there is too little, or by allowing alcohol to evaporate
if there is too much. The same approach is equally available
to the brewing and other chemical and process industries. For
applications requiring a higher degree of accuracy of the displacement,
limited space envelopes, or extreme temperature spans, Ixthus
can offer alternative non-contacting measurement solutions.
These include Kaman precision Inductive sensors and Matsushita
Laser Triangulation sensors.
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Divider Plate Presence/Absence
Detection
The Customer's requirements:
The customer is a major automotive components company located
in New York. They need to be able to sense the presence or absence
of a divider plate in the heater cores they manufacture. Because
of the design of the core, other sensors have been ineffective
in this application. The divider plate is installed to create
two chambers within the heater core. Fluid enters through the
inlet pipe and is diverted through the core tubes until exiting
through the outlet pipe.
The customer needs:
A thru-beam sensor capable of sending its signal in through
the inlet pipe, 'seeing around curves inside the heater core,
and exiting through the outlet pipe if the divider plate is
not in place.
A sensor that can distinguish between two signals: one that
travels into the heater core and exits immediately (when there
is no plate in place), and one that travels through the tubes
in the core before exiting (when a plate is in place). The difference
is determined by the strength of the signal leaving the core:
strong when no plate is present, weak when the plate is in place.
Migatron's Solution:
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The Migatron solution for this unusual
application is the TBT/TBR-600 thru-beam sensor. An adjustable
Sensitivity control provides highly accurate signal strength
detection. P1 on the receiver (TBR) is labelled sensitivity
adjustment. The LED is provided to show signal strength.
The sensor is factory set with P1 fully clockwise (cw),
making the LED solid red in colour. To achieve greater
sensitivity for smaller targets, turn P1 counter-clockwise
(ccw) so that the LED is greener in colour. This increases
the sensitivity of the unit. |
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Because of some unique requirements of this application, Migatron
worked very closely with the customer and was able to provide
them with a semi-custom unit to meet all of their specifications.
The unit was produced with exceptionally high gain to ensure
its responsiveness, and additional testing was done in Migatron's
lab on a variety of cores the customer produces to be effective
in all the different types of cores.
The customer has been using the TBT/TBR - 600 successfully for
several months now, and is working with Migatron to develop
a customised unit that will be incorporated into their automated
machinery for heater core quality assurance, as well as for
other products. Because of the versatility of this ultrasonic
thru-beam sensor, the customer was able to solve a long-standing
problem and increase the efficiency and accuracy of it's assembly
line.
Migatron is also working with other customers to design and
build customized units that will work in a variety of applications,
including fluid chambers in transmissions and air passages in
manifolds.
HIGH-SPEED COUNTING
The TBT/TBR-600 is an ideal sensor for any high-speed counting
application. It can count up to 12,000 items per minute. The
P2 control is used as an adjustable delay-- turn fully clockwise
to provide the slowest response time--180 items per minute.
Simply turn P2 counter-clockwise (faster) or clockwise (slower)
to respond appropriately to the speed of the targets moving
past the detect point
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Road Surface Variation Sensing
at Speed
The Customer's Requirements:
The customer is a private contractor doing road repair work
in a rural county in the south. They need to be able to sense
variations in the pavement (ruts, potholes, etc.) while travelling
at a speed that will not impede traffic or cause safety issues.
The customer needs:
A sensor that will give an accurate reading while travelling
at speeds of 45mph or more. Because of the possibility of road
debris (rocks, dust, gravel) the transducer must be durable
and scratch-resistant.
- A sensing range of 5" to 14".
- A non-contact sensor that can withstand harsh environmental
conditions: dust, moisture, vibration and debris.
- A sensor with a remote transducer that will be easy and
inexpensive to replace in event of damage.
- A threaded sensor for easy mounting.
- A sensor that has the capability to work with the customer's
controller that tells the unit when to transmit.
Migatron's Solution:
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The Migatron solution is the RPS-300T-14, which meets
or exceeds all of the customers' needs with it's 4"-14"
range and durable Teflon sensing face. It's remote transducer
allows the sensor head to be mounted in small spaces,
while the controller is out of the way and protected from
possible hazards. With the addition of the RPS-500 card,
analogue outputs of 0-10 VDC and 4-20mA are provided.
This allows precise distance measurement. |
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The RPS-300T-1 4 provides the customer with:
- A durable, single-piece, Teflon transducer that can be
used in potentially hostile environments. *A sensor with
a range of 4" to 14".
- A sensor with a remote transducer that can be mounted
in a small space, while keeping the controller in an easily
-accessible, "safe" environment.
- A sensor with adjustable zero and span controls.
- An analogue output of 4-20mA.
- A high frequency of 180 kHz, which will eliminate false
triggers due to ambient and background noise.
- Easy mounting because the remote transducer is a threaded
barrel measuring only 1.25" in diameter and 1.25"
in length.
- A solid-state sensor that has a virtually unlimited life
span and is maintenance-free.
The customer has been using the RPS-300T-14 for several months
now with great success. Twelve of the sensors are mounted on
each vehicle and the readings are fed into a PLC which generates
a graph showing precisely where repairs need to be made in the
roadway. The sensors are timed to read the pavement every 6",
50 even the smallest defects are being detected!
Not only is the customer pleased with the accuracy of the units,
but also they report that the time it takes to evaluate the
roadway has been decreased by over 90%.
To date, only three transducers have needed to be replaced due
to damage, at a minimal cost to the customer.
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Tank Level Monitoring in a
Muddy Environment
The Customer's Problem:
The customer needs to monitor the level of material in a tank.
The customer's problem is that if the transducer face gets covered
with mud the tank will overflow and spill all over their plant
floor. The customer needs a sensor that will shut off the pump
to the tank if the transducer were to get covered in mud, a
fail state output. The problem the customer was running into
was that the sensor he was using would turn the pump on if it
became covered in mud.
The customer needs:
- A sensor with a fail state of 4mA.
- A sensor that can withstand a hostile environment where
corrosion, dust, and humidity will be present.
- A sensing range up to 80".
- An analogue output of 4 -20mA.
- A self-contained sensor with quick disconnects cable.
Migatron's Solution:
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Migatron did not have a standard sensor that would meet
the customer's fail state requirement. The closest standard
sensor to the customer's needs was the Migatron RPS-426A-80
Q.D. However, the RPS-426A-80 Q.D. will read a maximum
output (20mA) in the customer's fail situation.
Migatron took on the challenge and designed a semi--custom
sensor from the RPS-426A-80 Q.D. to meet the customer's
needs. |
Migatron's team of engineers redesigned the electronics of the
RPS-426A-80 Q.D. to comply with the customer's request for a
4mA fail state. The new RPS-426A-80R Q.D. semi-custom sensor
will produce a fail state output of 4mA and 0VDC, depending
on the mode of operation. With an output of 4mA in the fail
state, if the customer's sensor were to become covered in mud,
the transducer cord cut, or the transducer itself failed, the
tank would not over fill. This also means that if the sensor
were in a non-detect state the output would be 4mA and 0VDC.
The customer was also concerned about the level of humidity
in the tank and that moisture might collect inside the unit
because of the two potentiometers on the back of the RPS-426A-80R
Q.D. Migatron offers a protective housing (TMF-30-MS) that screws
onto the back of the sensor. A liquid tight connector is used
with the TMF-30-MS so that when tightened, it seals and holds
the cord in place. This proves to be a good water resistant
system.
The RPS-426A-80R provides the customer with:
- A sensor with a low dropping output for a fail state of
4mA or 0V depending on the mode of operation.
- A sensor with a stainless steel transducer that is resistive
to corrosion, dust, and humidity. *A sensor that is easy
to mount and adjust.
- A high frequency of 150kHz to eliminate false triggers
from ambient or back- round noise.
- A sensor with an adjust-able range of 8" to 80".
- An operating voltage of 20 - 30VDC that is reverse polarity
protected.
- An output of 4 - 20mA and 0 - 10VDC, both that can be
inverted.
Migatron also does semi-custom work on any of the 100 plus sensors
that they manufacture. Since semi-custom projects are done on
existing sensors, the cost of the operation can be kept at a
reasonable price.
Migatron can also make complete custom sensors for the customer
with an OEM or other high volume applications in mind.
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Hostile Environment Non-Contact
Sensing
The Customer's Requirements:
The customer is a manufacturer of core sand producing equipment.
This equipment mixes sand and resin to the proper consistency
to be formed into the proper shape to displace molten metal
in a moulding operation.
The customer needs:
- A non-contact sensor able to be used in a non-lighted
area.
- A sensor with the ability to withstand a harsh foundry
environment specifically sand dust.
- A sensor that resists the vapours from the resin which
holds the mould together.
- A sensor that can operate in 100 degree temperature.
- A sensor that can control the minimum and maximum level
of sand in a filling hopper.
- A sensor with a maximum range of 75".
- A sealed self contained sensor.
- A narrow beam sensor.
- A sensor that is short circuit protected.
- A durable sensor.
Migatron's Solution:
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The RPS401 -80 was able to meet all of the customer's
requirements. The RPS401 -80 was mounted in the centre
and at the top rim of the hopper. It was protected by
a triangle/cone shaped steel hood supported by a rigid
bracket from three sides of the hopper. |
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As the hopper empties, the sensor detects the minimum level
of sand, which is the maximum desired range from the sensor.
In this application that distance is 75". At this point
the sensor turns off, activating the N.C. relay and sending
a signal to the PLC calling for more sand to be conveyed to
the hopper. When the sand reaches its maximum level, the minimum
desired range from the sensor, the sensor turns on. In this
application, that distance is 12". At this point the sensor
activates the N.O. relay and discontinues the signal being sent
to the PLC, thus causing the hopper to stop filling. The sensor
then stays in the "on" state until the maximum distance
is reached again.
The setup for this application is done by adjusting the range
control pot for the near point, and hysteresis control pot for
the far point. It should be noted that by using the N.O. output,
a sump pumping application can be accomplished.
The RPS401-80 provides the customer with:
- An easily installed stud mounted, self-contained ultrasonic
sensor.
- A Sensing Range of 8" to 80", which meets the
customer's need for a sensing range of 75 inches.
- A Narrow Sensing Beam.
- LED Indicator, for ease of set up.
- Short Circuit Protection.
- Reverse Polarity Protection.
- N.O. N.C. Solid State outputs.
- A Solid State sensor that will provide the customer with
a virtually unlimited, maintenance free, life-span.
- Hysteresis Option that allows the sensor to maintain the
proper high and low levels of product in the hopper.
The customer has been using the RPS-401-80 for this application
for over three years now with great success.
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Warm Acid Liquid Level Detection
The Customer Requirements:
The customer needs to monitor the liquid level of a warm acid
bath and provide a continual status report to a process control.
The bath tank is five feet deep.
The customer needs:
- A stainless steel transducer and housing to withstand
the acid bath.
- A threaded sensor for easy mounting.
- An operating frequency that eliminates ambient and background
noise.
- A consistent sensing range of at least 5ft.
- An analogue signal output of 4-20mA, inverted (20mA for
the top of the tank, 4mA for the bottom) -compatible with
their controllers.
- Use of available on-site voltage of 24 VDC to drive the
sensor.
Migatron's Solution:
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The Migatron solution is the RPS-426A-80, which solves
the customer's problem because it is a stud mounted, completely
self contained, stainless steel sensor. In addition, it
is a 20-30 VDC powered ultrasonic sensor. The RPS-426A,
is a simple four wire device, which features both voltage
and current outputs which can be used in a non-inverted
or inverted mode, providing the flexibility the customer
requires. |
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Zero and span controls are supplied for precise adjustments.
This allows the customer to scale the range to five feet, the
depth of the tank.
Because the RPS-426A is a sealed stainless steel transducer
in a stainless steel housing, it provides protection in hostile
environments.
Also, this ultrasonic sensor has a 8" to 80" range
and operates at a frequency of 150kHz.
The RPS-426A has built in short circuit protection for the outputs
as well as reverse polarity protection on the inputs.
The Stainless Steel barrel housing which is used is 30mm in
diameter by 100 mm in length.
The customer found Migatron's unique L.E.D. indicator very useful
for set up purposes, because the L.E.D. will illuminate green
when powered up and when detecting the L.E.D. will illuminate
yellow changing to red when detection is the strongest. Therefore
showing how well the target material is aligned.
The RPS-426A-80 provides the customer with:
- A Sensor in a Stainless Steel Housing, which can be operated
in Hostile Environments.
- A Self Contained Sensor, which is easily mounted.
- A sensing Range of 8 to 80".
- A Narrow Sensing Beam.
- High Frequency of 150kHz, which eliminates false triggers
due to ambient and background noise.
- Reverse Polarity Protection.
- Short Circuit Protection.
- An operating voltage of 20-30VDC, which will allow the
customer to use the available on-site voltage of 24 VDC.
- Outputs 0-10 volts, and 4- 20 mA .
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