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Load Cell 101 Webinar Slides

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Slides from our January 27th live webinar broadcast of our Load Cell 101 presentation with Albert and Jack. The presentation agenda includes: definitions, load cell basics, strain gages, moment and temperature compensation, calibration and performance.

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Load Cell 101 Webinar Slides

  1. 1. Load Cell 101 lnterface Webinar Wed nesd any with Albert & jack Interface 1 IN‘ A‘. .x-. inn. .i II. 'lA‘. l ms-
  2. 2. Agenda « Definitions - Load Cell Basics ~ Strain Gages « Moment Compensation - Temperature Compensation « Calibration - Performance ~ Applications - Q&A Interface _
  3. 3. Definitions « Axial Load - Calibration Additional definitions and - Capacity more are available in our ~ Deflection website library under: - Eccentric Load Load Cells / Load Cell « Hysteresis Terminology - Nonlinearity —- Output ~ Rated Output (RO) ~ Static Error Band (SEB) Interface _
  4. 4. What is a Load Cell? - Device that converts a force into an electrical signal ~ Designed to measure loads: ~ Tension ~ Compression - Both ~ No moving parts ‘it re - - No wear and tear " ~Q“r--7’57- , between main components / Interface _
  5. 5. Types of Load Cells Interface 11-1--——-jj l nan II Icovvmul, umc-e uu ’ ’ T’ l . g. .. ‘ Bending Beam 5.5 ' g , .—-. ,/.4: n——, "r -' — . » . 3 A». __, i ‘tnnv . -' . ._- e T I D I . ._, .__, _ ' ~31 Dual Bending Beam Column Style Interface _
  6. 6. Types of Load Cells Load Button S-Beam Interface BUMIMIN I Z AD‘lNClDl()0|Ck MIA
  7. 7. Anatomy of a LowProfileTM Load Cell Hub Strain Gage lnterconnectingwires Base Diaphragm Connector Interface _ ADVANCl. D I oucu MIA
  8. 8. Main Components - Flexure - Load bearing component - Deflects under load - Strain Gages - Measure strain of flexure '-°WP"°fi'e"“ Flexure - Form load cell's electrical circuit using aWheatstone bridge Flexure deformation changes gage resistance strain Gage T Ai~A. -u Ill -«min vim; inivin:
  9. 9. Flexure Design - Construction materials: 0 6 ~ 2024 aluminum « E4340 steel « I7-4 PH SS Design considerations: « Beam Thickness - Beam Height Beam functions: - Stress Concentration ~ Gage bonding location Beam Thickness Beam Height Interface _
  10. 10. Strain Gages I. Grid Lines 4: - Strain sensitive pattern 3 2. End Loops 4 > - Provide creep compensation 3. Solder Pads - Solder wires to gage 4. Fiducials 2 - Assist w/ gage alignment 5. Backing J - lnsulates and support foil P f ' - Bonded to flexure art“ “tram gage T Alivlfu III -«min uimi iuvin:
  11. 11. Gage Configurations « Linear E‘: i ~ Measure strain under bending l l _ ~ Mini Beam (MB Cells) « Shear ~ Measure strain under shear - LowProfi| eT"" cells - Poisson llIlI lllll - Measure strain under normal stress l* I if if - 2| 00 Series Column cells - Chevron ~ Measure strain under torsion i 5400 Series flange cells Interface _
  12. 12. Wheatstone ridge - Identical gages RED ~ Half in tension <’' E“) « Half in compression GREEN . ‘ ’ - WHITE Gage resistance varies. (+ SIG) (- SIG) - Increases under tension - Decreases under compression BLACK (- EXC) Interface _
  13. 13. Resistance Changes - Wire under tension strains: T j _s’_ - Cross section decreases I L I - Decreased current flow - Increased electrical resistance - Wire under compression strains: j— DI - Cross section increases I ~ Increased current flow l——-— L. ———-l - Decreased electrical resistance Interface j I‘I‘JIN: Al‘VAl'l Iiimm I ~. IiA<. i
  14. 14. Gage Area {no load condition) - No deflection in gage area - Designed to be weakest section G age Areas LowPmfi| e"‘ Load Cell SectionView Interface _
  15. 15. Gage Area (axial load applied) - Deforms under load - Shear stress concentration g Strain lines in gage area Not to scale} Interface
  16. 16. How does deformation change gage resistance? - Grid lines parallel to strain lines - Gage is under tension ‘ Resistance increases — Shear gage under tension Interface _
  17. 17. How does deformation change gage resistance? - Grid lines perpendicular to strain lines ~ Gage is under compression - Resistance decreases Gage under compression Interface _
  18. 18. Bending Application Interface -1 in’ )«‘. .A’. Ilili u<. hA um. -
  19. 19. Bending Beam — Tension 8:. Compression IEBIN COURESSIJI COWMSSKII IEISII SHGITEII Ei TIMXEH LMIR 6 Will Interface
  20. 20. Why do we make our own Strain Gages? « Proprietary Interface foil strain gages are thermally matched to the load cell material. ~ As a result our load cells do not require modulus compensation resistors. - This allows for far superior temperature performance along with higher output (typically 4mVN) at lower mechanical strain levels. ~ Higher output means higher resolution and better signal-to-noise ratio. Interface _
  21. 21. Moment Compensation - Reduces force measurement errors due to eccentric loads ~ Performed by - Loading cell eccentrically - Rotatingload - Recording output signal ~ Compensating to minimize errors Moment Setup T Al VA'I« Ililinh i um-~n UIUIH1
  22. 22. Moment Compensation Output Signal (Uncompensated) 280.0 ‘ A2780 V 2276.0 l 3274.0 3272.0 ' 3270.0 ' 268.0 266.0 0 135 180 225 270 315 360 Rotation (Degrees) 45 90 Output Signal (Compensated) 222.5 222.0 » 52215 a $2210 a 5 220.5 ~ 3 220.0 ~ ° 219.5 A 219.0 135 180 225 270 315 360 Rotation (Degrees) 0 45 90 Interface Alwlhx III - um: Vllllal mum:
  23. 23. eratnre Compensation * Reduces force measurement errors due to ambient temperature changes + Performed by * Recording output signal - Cold — Hot (I5 — I |5F) «v Undera No-Load condition + Adding compensating wire to minimize temperature induced errors Interface _
  24. 24. Temperature Compensation 12 1 1 UNCOMPENSATED _L 9 Zero Balance (lb; equivalent) c-h COMPENSATED NQIJBUIOINGID 0 20 40 60 80 100 120 140 Temperature (°F) Interface 2 AKW‘AN(tU Icmu UlA1:l. ‘l4lV(Nl
  25. 25. Calibration - Performed to verify load cell meets performance parameters _ g - Hysteresis - Non—| inearity - Static Error Band Calibration Setup T AL‘VA3I Ill -<1-«,1 an M1 in «nu:
  26. 26. Non-Linearity and ysteresis ado Pom BEST Fll’ snwsur une ---ZERO Bl! .ANCE-—— 40 6 0 20 0 FORCE, °/ o RATED LOAD Interface _
  27. 27. Static Error Band (SEB) 0 20 40 60 80 1 00 FORCE, % RATED LOAD Z AL~A. ‘1( In in-«Lt tun-. l.m-Irn
  28. 28. Performance Specifications -‘l-V10.’/ ‘»l*! .vlll0I. ‘i~‘ PAflAMETERS 1110 1210 1220 CAPACITY U. S. Models lb 300 $00.1K. 1K 10K 25K. 50K 1.5 2.5 5.10 100.250 . :0 04 - was :0 03 :0 06 =0 01 2001 :0 01 20025 20025 zonzs :0 25 __ gozs :0 25 . .. an mu an ‘ 1510115 l5loll5 ‘EH11 15roH5 -10lo45 __ -1Uio45 -10:0-'5 -101045 5510200 __ -550200 4350200 -65to200 0 _-an Ra . -55Io€0 -551090 -561090 -551090 :0 was xocme zom zooms soc-0'5 seems Ere: 0r. ot: p0:. =snorr - 1.4,-. x t0 0005 __ :0 0030 :0 K06 em: or. 00 ui-‘! uROI‘C -1.-. ;.x :0 0015 :0 00:5 :0 0015 :0 00:5 2 0 4 0 VDC MAX 3-‘ as ACCURACY - (MAX ERROR) 813 : Error BTH'O-'5 F5 <3 2 r 3&3 222 E» 3 " — Hi 1%: 8 150 5000 — mil 0002 005 E3 8': 8o k: .‘J'r: n R0-. » s'; :'IoL'~ML . Sol»: 0. -. ~1c. :0—% CAP De‘: -cL«: >r 141 R0-nch 0 :01 _ 0 m2 Cv: "«~: v;3n / T. R0-mrn 0 03 O 05 a10~.0.0 B132 «W 91121“ N. r. Fr; t/K: ‘-11 3950.09.95 059.1 15 — 07 15 43 118 pc0:a. ~.oep _‘_ Pc0:s. :0.sp PCO~: E-10-6P no rec uc rac 0003 0 Interface _ A. A‘llili—Il.1II1l"lll2
  29. 29. Applications — Iilaterials Testing ' i. . . i_ user"- Interface _
  30. 30. Applications — Aerospace )___” fir. . A ‘ ‘ ' | ‘r": l"' ii" ‘ , “‘ 0 ‘ : ‘_-'V>. .0 ‘ l~ ' '1 ‘ll '» ll l “vii, -‘. "«1 -; .1‘ l ‘ v~ ulv I - , ‘ , #55 iv': ;ll'l[fE l’fll»‘1v| l’) rq "‘l_"l l "H51. ' mm-‘. ulul1‘«. ‘{. um4.. i.-. u. -4,. l‘I 1(f1."4““l&f". ;|' 'l", _ij‘. t‘ ' ' 1.‘. "'7‘l‘i‘yr " ii ll? ‘'1 : V '- -‘ h " ill? 4‘: ,-. I l p -’ I‘ '~ ). m|ll| )ll'f“ , .“‘ 1lvs(u‘'""u"- ‘Y —‘ ‘ "fw Ill, .U"il. "Wmlu~’_ 41.. 'i" "' " '"""" “““'("(‘‘J" l‘“““‘lu. !‘n """“’ ” ' ‘. ,, . " 7. . ) ETC" "'''i " , .‘. ,"i. ‘.= ~n'§l “* ill. ‘a. .. . W, 1 ‘‘‘‘n) l~. . . a " . ’r'-De I . ll Interface _
  31. 31. Applications — RFC Mirror Lab ft . . "En: -4 M . . A GMT _x I 1 Interface _ A‘. um: 1-. v.; . llllillll.
  32. 32. Applications « Automotive + Oil & Gas * Medical ~+ | ndustria| Weighing &Automation ~ Robotics Interface 2 ~. .»v. .1.ii . -4.». wli'~‘lll2
  33. 33. Thank You! Interface 1 an: A1 . A-. Ilxii. -ti I I. l|A'-i c-Iv

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