Post on 02-May-2018
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CHOOSING THE RIGHT LOAD CELL
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Bending Beam
Miniature
S Type
Single pointweighbeam
BendingBeam
BendingBeam
Diaphragm
Clevis Pin
Diaphragmpancake
Cannister
MultipleColumn
SingleColumn
Column
Shearpancake
Donut
Donut
ShearBeam
Diaphragm Column
Types of Load Cells
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Scientific weighing
Process Weighing
Industrial weighing
Specialist ForceMeasurements
Retail weighing
Test &Measurement
Research/CalibrationForce measurement
OEM
Main Focus
Oil & Gas
Some Customers
Main Focus
Application Segments
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INDUSTRIAL W EIGHING
FORCEMEASUREMENT
RETAILW EIGHING
OFFICEW EIGHING
Application Segments
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Tension
Compression
Principle of the Load Cell
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10V
Principle of the Load Cell
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10V
LOAD
Principle of the Load Cell
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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How a Load Cell is Constructed
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Compression Tension
How a Load Cell is Constructed
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Elements of a Load Cell
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Elements of a Load Cell
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Elements of a Load Cell
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Unique Load Cell Characteristic
Load Cells form part of the structure that they are measuring
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Load Cell Specifications
Connection to structure
Measurement Type
RangeTemperature Range
Electrical Connection
Size
Accuracy
Environmental
Excitation
Weight
Overload protection
Signal O/PMounting considerations
Extraneous Loads
Sensitivity
Additional O/Ps
Internal External
Connection to measurement
system
Sensor Properties
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• So many combinations of specs are mutually
exclusive: Specifying a load cell is trading one
performance criteria against another.
– Example Pick 3 and you compromise the fourth
• High load capacity
• Small size
• High accuracy
• Immunity to extraneous loads
Specifying a Load Cell
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Mounting
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Mounting
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Mounting
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Mounting
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Mounting
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Mounting
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Mounting
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Mounting
40
Mounting
41
Mounting
42
Mounting
43
Mounting
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Mounting
45
Mounting
46
Mounting
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Mounting
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Mounting
49
Mounting
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Mounting
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Load Range
Usually same as load range
OverloadRange
ProgressiveDamage
Mechanical failure
Load Range
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10,000 100,000 1,000,000 Lbs1,000100100Load Range
Model 41
Model 75
Model 46
Model 45
Model UG
Model 31
Model 34
Model 11
Model RGM, RGH, RGF
Model RM, RH, RF
Model 81
Model 82
Model TH
Model 53
Model D
Specials
Model TG
Model 43
Model 73
Model MPB
Model 13
Model LFH-71
250 15000 50000 5000005 50
CompressionFatigue rated version
Tension BendingTension & Compression
Fatigue rated version
Model WG
Load
Ran
ge
Load Range
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TENSIONCOMPRESSION
Model 41
Model 11
Model 75
Model 31 Model 34
Model RGM,RGH,RGF
Model 47 Model 49
Model UG
Model 81
Model RM,RH,RF
Model 82
Model LFH-71
Model 73
Model MPB Model 13
Model TG
Model MBL Model 43
Model TH Model 53 Model D
Model WG Model GR Model SP
Accuracy
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100,000 lbs 10,000 lbs 1,000 lbs 100 lbs 10lbs
TENSION/COMPRESSION
COMPRESSION
TENSION
Model UG 0.03%0.02%0.03%0.02%Model 470.03%0.02%0.03%0.02%Model 49Model 41 Model 75
Model TG Model M PBModel WG Model 73Model TH
0.03%0.02%0.03%0.02%Model 47
Model 75Model 410.03%0.02%0.03%0.02%Model 49
Model RGM,RGH,RGFModel 31
Model WG Model 73Model 4310,000 lbs Model 73Model 73
Model MPB Model THModel MPB Model 53Model LFH-71Model D
Model RM,RH,RFModel 82 Model 82 Model 82 Model 81
Model UG0.03%0.02%0.03%0.02%Model 470.03%0.02%0.03%0.02%Model 49
Model 75Model 41
Model RGM,RGH,RGF
Model 34Model 31
Model LFH-71Model 43Model 13Model 73
Model 11
Model DModel 53
0.03%0.02%0.03%0.02%Model 490.03%0.02%0.03%0.02%Model 47Model UG
Model 41Model 75Model 31Model 34Model 11
Model 13 Model 13 Model 43Model 73 Model DModel 53 Model LFH-71
Model 41
Model 34Model 31Model 11
Model 13Model 43
Model DModel 53
Model 43
Model UG
Model RM,RH,RF
100,000 lbs 10,000 lbs 1,000 lbs 100 lbs 10lbsTE
NSIO
N/C
OM
PRESSIO
NC
OM
PRESSIO
NTE
NSIO
N
Model UG
0.03%
0.02%
0.03%
0.02%
Model 47
0.03%
0.02%
0.03%
0.02%
Model 49
Model 41
Model 75
Model TG
Mod el M PB
Model WG
Model 73
Model TH
0.03%
0.02%
0.03%
0.02%
Model 47
Model 75
Model 41
0.03%
0.02%
0.03%
0.02%
Model 49
Model RGM,RGH,RGF
Model 31
Model WG
Model 73
Model 43
10,000 lbs
Model 73
Model 73
Model MPB
Model TH
Model MPBModel 53
Model LFH-71Model D
Model RM,RH,RFModel 82
Model 82 Model 82 Model 81
Model UG
0.03%
0.02%
0.03%
0.02%
Model 47
0.03%
0.02%
0.03%
0.02%
Model 49
Model 75
Model 41
Model RGM,RGH,RGF
Model 34
Model 31
Model LFH-71
Model 43
Model 13Model 73
Model 11
Model DModel 53
0.03%
0.02%
0.03%
0.02%
Model 49
0.03%
0.02%
0.03%
0.02%
Model 47
Model UG
Model 41
Model 75
Model 31
Model 34
Model 11
Model 13Model 13
Model 43
Model 73
Model DModel 53
Model LFH-71
Model 41
Model 34
Model 31
Model 11
Model 13
Model 43
Model DModel 53
Model 43
Model UG
Model RM,RH,RF
Physical Size
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Stress Levels
Reduced below
non-fatigue
Rated load cells
-Lower sensitivity
High stress
points reduced
by strain gage
placement to
highest stress
area. Structure
cross sections
increased
Fatigue rated to 1000 million cycles compared to 1 million cycles
Fatigue Rating
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OFF AXIS LOADINGTORQUE
SIDE LOADING
Extraneous Loading
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Pancake Style load cells
have excellent off axis
immunity
Typically 20% side load
gives less than x% error
Pancake design
Extraneous Loading
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Poor off axis
performance due to
dimensional geometry
Miniature design
Distance from centerline to gauges
Distance from centerline to gauges
Extraneous Loading
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The larger the width to
height ratio the higher
the immunity to side
load
Column design
Poor Better Good Best
Extraneous Loading
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Multiple column
cells can reduce
effects of off axis
loading
Column design
Extraneous Loading
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Column design
Multiple column
cells can reduce
effects of off axis
loading
Extraneous Loading
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S Beam designs are
poor in side loading
immunity and therefore
poor in compression
S Beam design
Extraneous Loading
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The use of load
cells in tension
and with rod end
bearings
eliminates side
loading
S Beam design
Extraneous Loading
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Load Cells
Pancake
Product Range
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Load Cells
Pancake Miniature
Product Range
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Load Cells
CannisterPancake Miniature
Product Range
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Load Cells
CannisterPancake Miniature DonutStyle
Product Range
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Load Cells
CannisterPancake Miniature DonutStyle
Rod EndStyle
Product Range
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Load Cells
CannisterPancake Miniature Z BeamDonutStyle
Rod EndStyle
Product Range
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Load Cells
CannisterPancake Miniature Z BeamDynamic
Load
DonutStyle
Rod EndStyle
Product Range
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Load Cells
CannisterPancake Miniature Z BeamDynamic
Load
DonutStyle
Rod EndStyle
Special Applications
Product Range
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Load Cells
CannisterPancake Miniature Z BeamDynamic
Load
DonutStyle
Rod EndStyle
Special Applications
TensionCompression
TensionCompression
Compressiononly
Compressiononly
Ultra HighPrecision
Ultra HighPrecision
Fatigue Rated
Non-Fatigue Rated
0.03%
0.03%
0.02%
0.02%
0.03%
0.03%
0.02%
0.02%
Model 47
Model 45
Model 75
10,000 lbs
Model 73Model 73
Model 41
Model 460.03%
0.03%
0.02%
0.02%
0.03%
0.03%
0.02%
0.02%
Model 73Model 43
Model 49
Product Range
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Load Cells
CannisterPancake Miniature Z BeamDynamic
Load
DonutStyle
Rod EndStyle
Special Applications
Tension/CompressionMale thread
Tension/CompressionFemale Thread
Low Cost Compression Only
TensionCompression
Compressiononly
High CapacityCompression
MiniatureSubminiature
Model 31
Model 34
Model 53
Model 13
Model 11
Model LFH-71
Product Range
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Load Cells
CannisterPancake Miniature Z BeamDynamic
Load
DonutStyle
Rod EndStyle
Special Applications
Compression Only
Tension &Compression
100 to 200,000 lbs0.03%
Model UG
15,000 to 3,000,000 lbs0.25%
10,000 to 500,000 lbs0.03%
50,000 to 500,000 lbs0.1%
Model WG
Model MPB
Model TGModel TG
Product Range
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Load Cells
CannisterPancake Miniature Z BeamDynamic
Load
DonutStyle
Rod EndStyle
Special Applications
150 grms to 30,000 lbs
15,000 to 200,000 lbs
Compressiononly
Model TH
Model D
Product Range
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Load Cells
CannisterPancake Miniature Z BeamDynamic
Load
DonutStyle
Rod EndStyle
Special Applications
Male-MaleThread
Male-MaleThread
Male-FemaleThread
Male-FemaleThread
Female-FemaleThread
Female-FemaleThread
TensionTension
Compression
Model RGM
Model RM
Model RGH Model RH
Model RGF Model RF
Product Range
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Load Cells
CannisterPancake Miniature Z BeamDynamic
Load
DonutStyle
Rod EndStyle
Special Applications
100-20,000 lbs
TensionOnly
5-250 Lbs
Model 82 Model 81
Product Range
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Load Cells
CannisterPancake Miniature Z BeamDynamic
Load
DonutStyle
Rod EndStyle
Special Applications
10,000 lbs1000 lbs
Model DLN Model DLS
Product Range
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Load Cells
CannisterPancake Miniature Z BeamDynamic
Load
DonutStyle
Rod EndStyle
Special Applications
Clevis Pins
Build fromscratchspecial
Single PointCompression
Product Range
80
Load Cells
CannisterPancake Miniature Z BeamDynamic
Load
DonutStyle
Rod EndStyle
Special Applications
Clevis Pins
Build fromscratchspecial
Single PointCompression
StandardProduct
Specials
Product Range
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INDUSTRIAL WEIGHING
FORCEMEASUREMENT
RETAILWEIGHING
OFFICEWEIGHING
Market Segments: Weighing
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– Fast Response
– Long fatigue life
– Large temp range
– Majority: Industrial
– Minority:Hostile
– Low compliance
– Low to medium volume
– Medium to high
accuracy
– NIST traceable
– DC response
– Low cycle life
– Limited temperature range
– Majority: room environments
– Minority: salt and water
– Large deflections
– High volume
– High accuracy
– Low cost
– ‘Legal for trade’
Force Weighing
Market Segments: Weighing vs Force Measurement
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Difficult to seal
Environmental
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Barometric pressure
Single sided diaphragm
Hermetically sealed
50 lb canister example
Environmental
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Barometric pressure
Barometric pressure
Diaphragm eachside equalizes
pressure effects
Environmental
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High temp
connector
High temp
strain gages
High temp
solder
Aluminum only good to 120 F
Stainless good to 500 F
Environmental
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350 ohm
bridge with
mV/V output
Amplified output
0-5V
0-10V
4-20mA
Note: Miniature and high temperature load
cells do not have amplified outputs
Electrical
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Signal +ve
Ground
Supply +
2 mV/V
Signal = 20 mV maximum Noise = 1 mV
Signal to noise ratio = 20
(Digitizer error as much as 10%)
Noise Immunity
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Signal +ve
Ground
Supply +
15-32 V DC Supply
0-10V output
Internal amplifierfitted
Noise Immunity
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Signal +ve
Ground
Supply +
0-10V
Signal = 10 V maximum Noise = 1 mV
Signal to noise ratio = 10,000
(Digitizer error only 0.01%)
Noise Immunity