Technical Notes9. Technical Notes

Transcription

1 9 SI Units an Conventional Gavitational Units 9- Mechanical Popeties of Inustial Mateials 9- Linea xpansion Coefficients of Mateials 9- Pefixes of xponents (Base 0) of Decimal Numbes 9- xamples of Stain Gage Measuement 9- Pinciple of Self-tempeatue-compensation Gages (SLCOM Gages) 9- Tempeatue ffect of Lea Wies with -wie System 9- Compensation Metho of Tempeatue ffect of Lea Wies (3-wie System) 9- Influence of Isolation esistance 9- esistance Change of Stain Gage Bone to Cuve Sufaces 9-5 Compensation Metho of Diffeent Gage Factos 9-5 Misalignment ffect of Boning Stain Gages 9-5 Compensation Metho of ffects of Lea Wies xtension 9-5 Compensation Metho of Nonlineaity o of -gage System 9-6 Metho of Obtaining Magnitue an Diection of Pincipal Stess (osette Analysis) 9-6 Geneating Calibation Values base on Tip Paallel esistance Metho 9-6 How to Fom Stain Gage Biges 9-7 Typical Stain Gage Boning Poceue an Damppoof Teatment 9-9 elations between SI Units an Conventional Gavitational Unit 9-0 Tems to xpess Chaacteistics of Stain Gage Tansuces 9- quation to Calculate Centifugal Acceleation 9-3 Unit of Acceleation gal an Gavitational Acceleation g 9-3 Countemeasue if Initial Balance ( Balance) Cannot Be Taken 9-3 Gaphs to Obtain Powe/Wok, otating Spee an Toque 9-3 elation between Tansuce Output Signals in Stain an Voltage 9- Convesion of Stain Quantity (Voltage) Measue by Tansuces into Pope Physical Quantity 9- Connection to Calculate Aveage Output Voltage of Same Moel Tansuces 9- Avantages of emote-sensing Metho 9- Installation of Loa Cells to Hoppes o Tanks 9-5 How to Obtain Pope ate Capacity of Loa Cells 9-6 How to Obtain Accuacy of Loa Cell-base Weighing System 9-6 Diffeence between Stain Amplifies an Signal Conitiones 9-6 Diffeence between Constant Voltage System an Constant Cuent System in Bige xcitation 9-6 Pinciple of CST Metho 9-7 The eason Why Constant Cuent Bige xcitation is use fo Civil ngineeing Measuement with Cable xtene 9-7 TDS 9-7

2 9- TCHNICAL NOTS SI Units an Conventional Gavitational Units Quantity Foce Stess Pessue Toque Wok negy Powe SI Unit N Pa x 0 6 Pa x 0 Nm J W Gavitational Unit kgf.0976 x 0 kgf/mm.0976 x 0 7 kgf/cm.0976 x 0 5 kgfm.0976 x 0 kgfm.0976 x 0 PS x 0 3 Mechanical Popeties of Inustial Mateials Mateial Cabon steel (C0. to 0.5%) Cabon steel (C > 0.5%) Sping steel (quenche) Nickel steel Cast ion Bass (casting) Phospho bonze Aluminum Concete G ( + ) Linea xpansion Coefficients of Mateials Mateial Quatz glass Ambe Bick Tungsten Lumbe (gain i.) Molybenum Ziconium Coba Concete Titanium alloy Platinum Soa-lime glass SUS 63 SUS 630 Cast ion NiCMo steel Young's Moulus (GPa) to to 9 Linea xp. Coef to to Sheaing Moulus G (GPa) to to 3 Mateial Beyllium Common steel Inconel X Nickel Gol SUS 30 Beyllium coppe Coppe Bass 0-T aluminum 0-T aluminum Magnesium alloy Lea Acylic esin Polycabonate ubbe Tensile Stength (MPa) Poisson's atio 363 to 0.8 to to to to to to to to to to Linea xp. Coef Appox. 65 to Appox. 77 (x 0 6 /) xamples of Stain Gage Measuement of Tensile/Compessive Stess () Quate Bige System(-gage System) See figue below. If a stain gage is bone on a suface of a pilla which eceives unifom loa fom one iection an the gage axis is aligne to the iection, stess is calculate by the following equation : Stess = 0 whee, : Young's moulus (efe to table "Mechanical Popeties of Inustial Mateials" at the left.) 0 : Inicate stain An, the loa W applie to the pilla is obtaine by the following equation: Loa W = A whee, A : Coss-sectional aea of the pilla W g g Stain gage 3 Bige excitation Tensile/Compessive Stess Measuement with -gage System () Half Bige System(-gage System) If anothe stain gage is bone to the pilla at a ight angle to the loaing iection an gages ae connecte to ajacent sies of the bige, the suface stess on the pilla is expesse by the following equation: Suface Stess whee, : Poisson's atio W g g g 0 g e0 Output voltage e0 Pefixes of xponents (Base 0) of Decimal Numbes Facto Pefix Symbol Facto Pefix Symbol yotta zetta exa peta tea giga mega kilo hecto eca Y Z P T G M k h a eci centi milli mico nano pico femto attp zepto yocto c m μ n p f a z y Tensile/Compessive Stess Measuement with -gage System If moe stain gages ae bone to the opposite sie of the pilla to eliminate bening stain an -gage system is aopte, the suface stess is calculate by the following equation: 0 Suface Stess () 9-

3 9- Bening Stess Measuement () -gage System See figue below. If a stain gage is bone on a suface of a ectangula section of a cantileve which one sie en is fixe an loa W is applie to anothe sie, the suface stess which bone stain gage etect is as follows : = Stain is obtaine by the following equation: 6WL bh whee, b: With of cantileve h: Thickness of cantileve L: Distance fom the loa point to the cente of stain gage quation of Stain on Beams Stain on beams is obtaine by the following equation : M Z whee, M: Bening moment (efe to Table ) Z: Section moulus (efe to Table ) : Young's moulus ((efe to table "Mechanical Popeties of Inustial Mateials," page 9-) Typical shapes of beams an thei bening moments M an section mouli Z ae shown in Tables an. Table. Typical quations to Calculate Bening Moment Shape of Beam Bening Moment M TCHNICAL NOTS L Stain gage h Bening Stess Measuement with -gage System W b () -gage System (Ajacent Sie Bige Connection) As illustate below stain gages bone symmetically on the font an ea sufaces of the cantileve outputs plus an minus signals, espectively, with an equal absolute value. If these gages ae connecte to ajacent sies of the bige, the output of the bige coesponing to the bening stain is ouble an the suface stess σ at the stain gage boning site is obtaine by the following equation: The ajacent sie active -gage system cancels out the output of stain gage coesponing to the foce applie in the axial iection of the cantileve. L Table. Typical quations to Calculate Section Moulus Coss Section Section Moulus Z Stain gage Stain gage W Bening Stess Measuement with -gage System 9-

4 9-3 TCHNICAL NOTS Tosional an Sheaing Stess Measuement of Axis When an object is twiste, sheaing stess occus. At the same time, towa iections incline by 5 fom axial line, tensile stess an compessive stess, which ae equivalent to the sheaing stess, occu. In measuement of axial twist une simple sheaing stess conition, a stain gage oes not iectly measue the sheaing stess. Instea, a stain gage etects tensile o compessive stain esulte fom tensile o compessive stess simultanusly geneate with the shaing stess. These stess conitions on a suface of axis can be illustate below. Tensile stess () Stess Measuement with o -gage System o -gage system inceases stain output by (-gage system) o times (-gage system), because each stain gage in o -gage system etects equal stains. To calculate eal stain, ivie measue stain by (-gage system) o (-gage system). Fo axial stain measuement, the o -gage system is use to eliminate stain cause by bening moment. Also, fo measuement of tensile stain an compessive stain, stain gages ae symmetically positione fom the cente of the axis as shown below. Tensile stain Compessive stain Sheaing stess Compessive stess (3) Application to Toque Measuement Stain on the suface of the axis is popotional to the toque applie to the axis. Thus, the toque is obtaine by etecting the stain on the suface. Sheaing stess istibute on the lateal section is balance with the applie toque T, establishing the following equation: Sheaing stain is efine as illustate below, an the magnitue is calculate by the following equation: G whee, G: Sheaing moulus ((efe to table "Mechanical Popeties of Inustial Mateials," page 9-) : Sheaing stess A B T =. Zp whee, Zp: Pola moulus of section Conveting sheaing stess in above equation to tensile stain, equation can be mentione as follow: T 0Zp The pola moulus of the section is specific to each shape of the coss-section as follows: Coss Section Pola Moulus of Section Zp l When the axis is twiste, point A moves to point B, theeby initiating tosional angle. () Stess Measuement with -gage System Bon the stain gage on the twiste axis in the iection incline by 5 fom the axial line. The elation between stain 0 an stess is expesse with the following equation to calculate tensile o compessive stess : whee, l 0 + l : Inicate stain : Young's moulus (efe to table "Mechanical Popeties of Inustial Mateials," page 9-) : Poisson's atio 0 Stess an sheaing stain ae equal in magnitue, an thus, A stain gage toque tansuce can be esigne using the above elational expession of 0 an T. Obtain 0 fom the allowable stess fo the mateial, an etemine the with of the axis which is matche with the magnitue of the applie toque. Then, amplify the stain output with a stain amplifie an ea the output voltage with a measuing instument. 9-3

5 9- Pinciple of Self-tempeatue-compensation Gages (SLCOM Gages) The measuing object an the esistive element of the stain gage have linea expansion coefficients S an g, espectively. Then, the stain gage bone on the suface of the object povies a themally-inuce appaent stain T pe that is expesse with the following equation : Themally-inuce appaent stain output (μm/m pe C) T S g Ks whee, : esistive tempeatue coefficient of esistive element Ks : Gage facto of stain gage μm/m pe C Tempeatue ( C) μm/m pe C esistive element (g) Measuing object(s) Self-tempeatue-compensation stain gages ae esigne to ajust esistive tempeatue coefficient of thei esistive elements to linea expansion coefficient of measuing objects in oe to get T close to zeo. When bone to a suitable mateial, Kyowa's selftempeatue-compensation gage (SLCOM gage) minimizes appaent stain in the compensate tempeatue ange to.8 μm/m pe (gaph below shows appaent stain output of 3-wie stain gages). Typical Tempeatue Chaacteistics of Self-tempeatue-compensation Foil Gage g Compensation Metho of Tempeatue ffect of Lea Wies (3-wie System) Fo effective self-tempeatue-compensation, SLCOM gages aopt the -gage system. Howeve, if the lea wie cable is the -wie system, stain output fom the bige is affecte by tempeatue effect of the lea wie. To avoi such avese effect, the 3-wie system is aopte. If 3 lea wies ae connecte to a stain gage as shown below, a half lea wie esistance is applie to the ajacent sie of a bige to compensate tempeatue effect of lea wies in bige output. Tempeatue effect of lea wies which is connecte to a measuing instument outsie of bige can be ignoe because input impeance of measuing instument is high. Fo pecaution of usage of 3-wie system, 3 lea wies shoul be the same type, length, an coss-section to equalize tempeatue effects of each lea wie. If lea wies ae expose to sunlight iectly, coating colo also shoul be the same. g l l l l l g 3 l l l 3 TCHNICAL NOTS Tempeatue ffect of Lea Wies with -wie System Lea Wie Moel L-5 L-9 L-6 N(Polyeste-coate coppe cable) *0Ω gage Coss-section ecipocating esistance Appaent Stain* Aea of Conucto of m long lea wie with m xtension (mm ) appox. (Ω) appox. (μm/m pe C) Themally-inuce appaent stain (μm/m pe C) is calculate by the following equation. l gl Ks whee, g: esistance of stain gage (Ω) l: esistance of lea wies (Ω) Ks: Peset gage facto of stain amplifie, usually.00 : esistive tempeatue coefficient of coppe wie ( / pe C 3.9 x0 3 Influence of Isolation esistance Isolation esistances of stain gages incluing lea wies o not affect measue values if they ae highe than 00 MΩ. Howeve, if they change astically uing measuement, eos may occu in measue values. Stain gage g Isolation esistance Input Bige Cicuit Designe with Isolation esistance Output 9-

6 9-5 TCHNICAL NOTS If the isolation esistance escens fom to in the figue above, eo stain is : g ( ) Ks Fo example, g = 0 Ω (esistance of stain gage) Ks =.00 (Gage facto of stain gage) = 000 MΩ (Oiginal isolation esistance) = 0 MΩ (Change isolation esistance) Then, the eo stain is appoximately 6 μm/m. Such eo is no matte in geneal stain measuement. In pactice, howeve, if isolation esistance is lowee, is not constant an be astically change ue to envionment change, such as tempeatue an humiity. In aition, it is impossible to specify insetion place of isolation esistance,, in cicuit. Thus, be caeful about influence of isolation esistance. esistance Change of Stain Gage Bone to Cuve Suface The stain occuing on the esistive element of a stain gage bone to a cuve suface may be expesse by the following equation: t t whee, t : Thickness of gage base plus ahesive laye : aius of gage-bone suface Fo example, if a uniaxial KFG gage of which the gage base incluing the ahesive laye is 0.05 mm thick, is bone to a cuve suface of.5, the stain gage aleay eceives stain about 5000 μm/m. If the gage facto Ks is.00, / 0000 μm/m If the gage esistance is 0 Ω, it inceases by appoximately. Ω. If the gage is bone insie the cuve, the esistance eceases. esistive element Gage base t t Compensation Metho of Diffeent Gage Factos If the gage facto of the stain gage is iffeent fom that (.00) of the stain amplifie, the eal stain can be obtaine by the following equation :.00 Ks 0 whee, 0: Measue stain Ks: Gage facto of stain gage Misalignment ffect of Boning Stain Gages Stain 0 misaligne by angle fom the iection of the pincipal stain is calculate by the following equation : 0 cos If = ( : Poisson's atio) une the uniaxial stess conition, 0 cos Stain iection 0 Compensation Metho of ffects of lea wies xtension If the lea wie o cable is extene with the -gage o -gage system, aitional esistance is initiate in seies to the stain gage, theeby eceasing the appaent gage facto. Fo example, if a 0 m long lea wie with 0.3 mm conuctos is use, the gage facto eceases by %. In the case of the -gage system (tansuce), the extension eceases the bige excitation too. In these cases, the eal stain can be obtaine by the following equation (supposing the gage facto Ks is.00) : l g i whee, i : Measue stain g: esistance of stain gage l : Total esistance of lea wies (Fo ecipocating esistance, see the table below.) One-way esistance in the case of 3-wie system Stain Gage Bone on Cuve Suface ecipocating esistance of lea wies Coss-section (mm) Numbe of Stans/ Wie Diam. (mm) 7/0. 0/0. /0.8 0/0.8 ecipocating esistance pe 0 m (Ω) emaks (Moels) L-6 L-9 L- L-5 9-5

7 9-6 Compensation Metho of Nonlineaity o of -gage System An eo of nonlineaity in high-elongation stain measuement with -gage system can be foun by calculating eal stain in the following equation : 0 0 whee, 0: Measue stain Metho of Obtaining Magnitue an Diection of Pincipal Stess (osette Analysis) Geneally, if a iection of a pincipal stess is uncetain in stuctue stess measuement, a tiaxial osette gage is use an measue stain values ae calculate in the following equation to fin the iection of the pincipal stess. (Following equation is only fo specifie angle tiaxial osette gages.) Geneating Calibation Value base on Tip Paallel esistance Metho When extening lea wies by seveal hune metes o fining accuate calibation values, the tip paallel esistance metho is aopte. The paallel esistance c can be calculate by the following equation : g c g Ks whee, g: esistance of stain gage Ks: Gage facto of stain gage : Calibation stain value g c TCHNICAL NOTS () ega a b c as the fowa iection. () Angle is: c Angle of the maximum stain to the a axis when a > c ; 90 o Angle of the minimum stain to the a axis 5 o when a < c. Compaison between a an c in magnitue inclues plus an minus signs. Max. pincipal stain max ac Min. pincipal stain min ac min omax b max omin a a b b c a b b c Diection of pincipal stain (fom a axis) b a c tan a c Max. sheaing stain max a b b c Calibation Stain Value 00 μm/m 00 μm/m 500 μm/m 000 μm/m 000 μm/m Max. pincipal stess max ac a b b c xamples of Calibation Stain Value an esistance (g = 0 Ω, Ks =.00) esistance c (appox.) 600 kω 300 kω 0 kω 60 kω 30 kω Min. pincipal stess min Max. sheaing stess ac max a b b c : Poisson s atio : Young s moulus (efe to table "Mechanical Popeties of Inustial Mateials, page 9-.) a b b c 9-6

8 9-7 TCHNICAL NOTS How to Fom Stain Gage Biges No. 3 5 Name -active-gage -wie system Numbe of gages: -active-gage 3-wie system Numbe of gages: -active-gage (ual seies gages) -wie system (fo cancel bening stain) Numbe of gages: -active-gage (ual seies gages) 3-wie system (fo cancel bening stain) Numbe of gages: Active-ummy -gage system Numbe of gages: Sample Application Uniaxial stess (Unifom tension/compession) Uniaxial stess (Unifom tension/compession) Uniaxial stess (Unifom tension/compession) Uniaxial stess (Unifom tension/compession) Active gage Bening Bening Uniaxial stess (Unifom tension/compession) Dummy gage g g g g g g g g g g g g Cicuit g g Output KSO KS : Gage facto O : Stain : xcitation voltage : Output voltage g: Gage esistance : Fixe esistance KSO KS : Gage facto O : Stain : xcitation voltage : Output voltage g: Gage esistance : Fixe esistance KSO g Stain g Stain + O Suitable fo une envionment of less ambient tempeatue changes; no tempeatue compensation. x output No tempeatue themal effect of lea wies cancele. x output No tempeatue bening stain cancele. x output : Fixe esistance = g + g e.g. g & g ae 60-ohm gages, if using a DB-0A. KSO g g No tempeatue g Stain g Stain bening stain cancele; + O themal effect of lea wies : Fixe esistance cancele. = g + g x output e.g. g & g ae 60-ohm gages, if using a DB-0A. KSO KS : Gage facto O : Stain : xcitation voltage : Output voltage g : Stain: O : Fixe esistance g Stain: 0 emaks Tempeatue themal effect of lea wies cancele. x output Bige Box DB-0A/350A g g g g g g 6 Othogonal* -active-gage system Numbe of gages: * at a ight angle g g Uniaxial stess (Unifom tension/compession) g g KSO : Poisson's atio g g : Gage esistance g Stain : O g Stain : O : Fixe esistance Tempeatue themal effect of lea wies cancele. x (+) output g g 7 -active-gage system (fo bening stain measuement) Numbe of gages: g g Bening stess g g KSO g Stain : O g Stain : O : Fixe esistance Tempeatue themal effect of lea wies cancele; compessive/ tensile stain cancelle. x output g g 8 Opposite sie -active-gage -wie system Numbe of gages: g g Uniaxial stess (Unifom tension/compession) g g KSO g Stain : O g Stain : O : Fixe esistance No tempeatue x output bening stain cancele by boning to the font an ea. g g 9-7

9 9-8 No. 9 0 Name Opposite sie -active-gage 3-wie system Numbe of gages: -active-gage system (fo bening stain measuement) Numbe of gages: Sample Application g 3 g g Uniaxial stess (unifom tension/compession) g g g Bening stess g g g Cicuit g g g 3 e0 Output KS0 g Stain0 g Stain0 Fixe esistance e0 KS0 g g 3 Bening stain g g Bening stain 0 0 emaks No tempeatue themal effect of lea wies Cancele; x output bening stain cancele by boning to the font an ea. Tempeatue themal effect of lea wies cancele; compessive/ tensile stain cancele. x output Bige Box DB-0A/350A g g g gg3g TCHNICAL NOTS Othogonal -active-gage system Numbe of gages: g g g 3 g g g g g 3 KS Poisson's atio e0 g g 3 Stain g g Stain Tempeatue themal effect of lea wies cancele. x (+) output g g g3g 3 Active-ummy -gage system Numbe of gages: -active-gage system (fo twisting stain measuement) Numbe of gages: g g3 Dummy g gages g Active gages Uniaxial stess (unifom tension/compession) g g g g g g g 3 g e 0 gg3 Stain gg Stain 0 e 0 KS0 KS0 0 g Twisting stain g Twisting stain 0 0 Fixe esistance Tempeatue themal effect of lea wies Cancele; x output bening stain cancele by boning to the font an ea. Tempeatue themal effect of lea wies cancele. x output g g g3g g g ggg3g -active-gage system (fo twisting stain measuement) Numbe of gages: g g g g g g3 g g3 g g g g 3 e 0 KS0 g g 3 Twisting stain 0 g g Twisting stain 0 Tempeatue themal effect of lea wies cancele. x output 5 -active--gage system (fo aveage stain measuement) Numbe of gages: g g g 3 g g g g g3 g g 3 g g e 0 0 KS Fixe esistance g = =g =g =g 3=g No tempeatue aveage stain x output g g g g3 elation between stain an voltage The output of a stain gage bige is expesse as a stain quantity (μm/m) o an output voltage (mv/v o μv/v) against the bige excitation. The stain quantity an the output voltage have the following elation: e0 KS0 If the bige excitation = V an the gage facto Ks =.00, e0 = 0. Thus, a stain output is always times lage than a bige output voltage. e.g..5 mv/v = 500 μv/v 3000 μm/m 9-8

10 9-9 TCHNICAL NOTS Typical Stain Gage Boning Poceue an Damppoof Teatment The stain gage boning poceue iffes epening on the type of the ahesive applie. The esciption below applies to a case whee the lea-wie-equippe KFG gage is bone to a mil steel test piece with a typical cyanoacylate ahesive, CC-33A. The amppoof teatment is in the case of using a butyl ubbe coating agent, AK-. Like awing a cicle with sanpape (#30 o so), polish the stain gage boning site in a consieably wie aea than the stain gage size. (If the measuing object is a pactical stuctue, wipe off paint, ust an plating with a gine o san blast. Then, polish with sanpape.) When the ahesive is cue, emove the polyethylene sheet an check the boning conition. Ieally, the ahesive is slightly potue fom aoun the stain gage. Using an absobent cotton, gauze o SILBON pape ippe in a highly volatile solvent such as acetone which issolves oils an fats, stongly wipe the boning site in a single iection to emove oils an fats. ecipocate wiping oes not clean the suface. Afte cleaning, mak the stain gage boning position. Make sue of the font (metal foil pat) an the ea of the stain gage. Apply a op of ahesive to the ea face an immeiately put the stain gage on the boning site. (Do not spea the ahesive ove the ea face. If so, cuing is avesely acceleate.) If the ahesive is wiely potue fom aoun the gage base, emove the potuing ahesive with a cutte o sanpape. Place gage leas in a slightly slackene conition. Put up the lea wie befoe the potion whee the ahesive is applie. Place a block of the coating agent below the lea wie with gage leas slightly slackene. Cove the stain gage with the accessoy polyethylene sheet an stongly pess the stain gage ove the sheet with a thumb fo appoximately minute (o not etach miway). Quickly pefom steps 3 an. Othewise, the ahesive is cue. Once the stain gage is put on the boning site, o not put it up to ajust the position. Completely cove the stain gage, potue ahesive an pat of the lea wies with anothe block of the coating agent. Do not tea the block to pieces but slightly flatten it with a finge to closely contact it with the stain gage an pat of the lea wies. Completely hie potusions incluing gage leas behin the coating agent. 9-9

11 9-0 elations between SI Units an Conventional Gavitational Unit Foce SI Unit 0 mn 0 mn 30 mn 50 mn 00 mn 00 mn 300 mn 500 mn N N 3 N 5 N 0 N 0 N 30 N 50 N 00 N 00 N 300 N 500 N kn kn 3 kn 5 kn 0 kn 0 kn 30 kn 50 kn 00 kn 00 kn 300 kn 500 kn MN MN 3 MN 5 MN Conventional Unit igits 5 igits.00 gf.039 gf gf gf 0.0 gf 0.39 gf gf gf 0.0 gf 03.9 gf gf gf.00 kgf.039 kgf kgf kgf 0.0 kgf 0.39 kgf kgf kgf 0.0 kgf 03.9 kgf kgf kgf.00 tf.039 tf tf tf 0.0 tf 0.39 tf tf tf 0.0 tf 03.9 tf tf tf.097 gf.039 gf gf gf 0.97 gf 0.39 gf gf gf 0.97 gf 03.9 gf gf gf.097 kgf.039 kgf kgf kgf 0.97 kgf 0.39 kgf kgf kgf 0.97 kgf 03.9 kgf kgf kgf.097 tf.039 tf tf tf 0.97 tf 0.39 tf tf tf 0.97 tf 03.9 tf tf tf Pessue/Stess SI Unit 00 Pa 00 Pa 300 Pa 500 Pa kpa kpa 3 kpa 5 kpa 0 kpa 0 kpa 30 kpa 50 kpa 00 kpa 00 kpa 300 kpa 500 kpa MPa MPa 3 MPa 5 MPa 0 MPa 0 MPa 30 MPa 50 MPa 00 MPa 00 MPa 300 MPa 500 MPa Toque/Tosion Conventional Unit.00 gf/cm.039 gf/cm gf/cm gf/cm 0.0 gf/cm 0.39 gf/cm gf/cm gf/cm 0.0 gf/cm 03.9 gf/cm gf/cm gf/cm.00 kgf/cm.039 kgf/cm kgf/cm kgf/cm 0.0 kgf/cm 0.39 kgf/cm kgf/cm kgf/cm 0.0 kgf/cm 03.9 kgf/cm kgf/cm kgf/cm.00 tf/cm.039 tf/cm tf/cm tf/cm Calculate base on a convesion facto of kg/ = k, an 5th igit is oune. SI Unit Conventional Unit Calculate base on a convesion facto of kgf = N, an 5th o 6th igit is oune. 00 mnm 00 mnm 300 mnm 500 mnm Nm Nm 3 Nm 5 Nm.00 kgfcm.039 kgfcm kgfcm kgfcm 0.0 kgfcm 0.39 kgfcm kgfcm kgfcm Acceleation 0 Nm.00 kgfm 0 Nm.039 kgfm SI Unit 0 m/s 0 m/s 30 m/s 50 m/s 00 m/s 00 m/s 300 m/s 500 m/s 000 m/s 000 m/s 3000 m/s 5000 m/s 0000 m/s Conventional Unit.00 G.039 G G G 0.0 G 0.39 G G G 0.0 G 03.9 G G G 00 G 30 Nm 50 Nm 00 Nm 00 Nm 300 Nm 500 Nm knm knm 3 knm 5 knm 0 knm 0 knm 30 knm 50 knm kgfm kgfm 0.0 kgfm 0.39 kgfm kgfm kgfm 0.0 kgfm 03.9 kgfm kgfm kgfm.00 tfm.039 tfm tfm tfm Calculate base on a convesion facto of 00 knm 0.0 tfm G = m/s, an 5th igit is oune. Calculate base on a convesion facto of kgf/ = Nm, an 5th igit is oune. TCHNICAL NOTS 9-0

12 9- Tems to xpess Chaacteistics of Stain Gage Tansuces TCHNICAL NOTS Common to All Tansuces ate Capacity Design value of the uppe limit in the measuing ange. ate Loa Uppe limit of loa at which the tansuce pefoms to the specifications. Oveloa Loa exceeing the ate capacity. Safe Oveloa ating Maximum oveloa which may not cause any pemanent change to state specifications, expesse in pecentage of the ate capacity. Ultimate Oveloa ating Maximum oveloa which can be applie without causing any stuctual amage, expesse in pecentage of the ate capacity. ate Output Value obtaine by subtacting the output une no loa fom the output une the ate capacity. Usually, it is expesse in mv/v, ma o equivalent stain. ate Output Voltage ate output expesse with the output voltage at the open en. It is expesse togethe with the excitation voltage. ate Output Cuent ate output expesse with the cuent flowing when connecte to a pescibe loa impeance. It is expesse togethe with the excitation voltage an loa impeance ate Output quivalent Stain ate output expesse with a value convete into stain, with the gage facto.00. Sensitivity atio of changing output to changing loa. Usually, it is expesse in mv/v o μm/m (micostain) pe -V excitation voltage. Calibation Constant atio of the ate loa to the ate output. Nonlineaity Maximum eviation of output between the calibation cuve in the inceasing loa cycle an the efeence line (staight line awn fom the output une no loa to the ate output une the ate capacity); expesse in pecentage of the ate output. ate output Output 0 a efeence line Loa C ate capacity Nonlineaity (% O) = a x 00 Hysteesis Diffeence of output between the calibation cuve tace in the inceasing loa cycle an that in the eceasing loa cycle. Usually, the calibation cuve is ecipocate between the null loa an the ate capacity an the maximum iffeence in outputs coesponing to the same loa is efine as the hysteesis, expesse in pecentage of the ate capacity. ate output Output 0 b Loa C ate capacity Hysteesis (% O) = b x 00 Natual Fequency Fequency ue to fee vibation of the tansuce une no loa. Fequency esponse ange Fequency ange in which the output can espon to the input at the same amplitue an phase within cetain ange of eo when the input is a steay state sine wave. xcitation Voltage Voltage applie to the input teminal of tansuce. ecommene xcitation Voltage Maximum excitation voltage with which the tansuce can pefom to the specifications. Safe xcitation Voltage Maximum excitation voltage with which the tansuce may not pefom to the specifications but when the ecommene excitation voltage is applie again, the tansuce pefoms to the specifications. Input/Output esistance esistance of input o output teminal. Use of the tem is limite to the inication of the nominal esistance of an input o output teminal. Input Teminal esistance esistance between input teminals with output teminals open une no loa. Output Teminal esistance esistance between output teminals with input teminals open une no loa. Tempeatue ffect on Zeo Balance Change of zeo ue to change of ambient tempeatue; expesse as a change of zeo pe C in pecentage of the ate output (xx% O/ C). Tempeatue ffect on Output Change of gain ue to change of ambient tempeatue, expesse as a change of zeo pe C in pecentage (xx%/ C). Compensate Tempeatue ange Tempeatue ange which guaantees that the tansuce pefoms to the specifications with ega to tempeatue effects on output an zeo balance. Safe Tempeatue ange Tempeatue ange in which the tansuce may not pefom to the specifications but oes not eceive any pemanent change in the specifications 9-

13 9- epeatability Maximum iffeence between output vaiables initiate by epeately applying the same loa une the same conitions. Usually, it is measue une the ate loa an expesse in pecentage of the aveage ate output. Zeo Balance Output une no loa with the tansuce place in the pescibe postue. Usually, it is expesse in mv/v, μm/m o pecentage of the ate output. Zeo Stability Degee at which the tansuce keeps the zeo une pescibe conitions. Stability Capability of the tansuce to keep the chaacteistics fo a compaatively long tem. Unless note, it is the capability to maintain the chaacteistics such as calibation facto an nonlineaity obtaine at the initial calibation, une oom conitions an fo a pescibe peio. If it is expesse by quantitatively numeic values, stability can be calle as "egee of stability". Intefeence With a multiple component tansuce, effects of the ate output applie to one component on output signals of othe components ae expesse in pecentage of the ate output of each component ecommene Tightening Toque Tightening toque equie to let the tansuce pefom to the specifications. esonance Fequency Fequency of input mechanical vibation causing maximum esponse output of the tansuce. Cycling Life Minimum numbe of epeate opeations une the ate o pescibe loa without exceeing allowable anges of specifie chaacteistics. Degee of Potection Degee of potection against invasion of a soli matte o wate; expesse using IP ating expesse in IC 6059 Weight xpesse in kg o g. If items othe than the mainfame ae inclue, the fact is note. Mateial Mateial of the mainfame, bottom panel o cable outlet is expesse using the type coe expesse in JIS. Suface teatment such as plating o painting is also note. Cable Cable to be connecte to the tansuce by the connecto o the cable iectly to the intenal cicuit. Nominal coss section of conucto, numbe of conuctos, mateial of shiel o sheath, length an nominal oute iamete an conition of the tip ae state. Loa Cells Zeo Float Zeo float ue to application of one cycle of ate tension an compession loas; expesse in pecentage of the ate output. It is also calle cyclic zeo shift. Compession loa Output ate output Pessue Tansuces Line Pessue (efeence Pessue) efeence pessue fo iffeential pessue measuement with iffeential pessue tansuces Acceleation Tansuces Centoi (Cente of Seismic Mass) Location of the cente of gavity whee acceleation is concentately applie. Damping atio atio of actual amping to citical amping Tansvese Sensitivity Tansuce's sensitivity to acceleation in tansvese iection o othe foce affecting in tansvese iection Sensitive Axis Axis in the sensitive iection of acceleation tansuce Mounte esonance Fequency esonance fequency measue by mounting the tansuce to a shake. Displacement Tansuces Measuing Foce (Pull out Foce) eaction foce of ial gage o tension of wie: expesse in N. Toque Tansuces 3 Zeo float = a x 00 (% O) Moment of Inetia Magnitue of the enegy with which an object ties to maintain the status. In otational motion, it makes it ifficult fo an object to change its angula motion in elation with the weight an shape. a ate capacity Note: Aow iection may be evese. Tension loa TCHNICAL NOTS 9-

14 9-3 TCHNICAL NOTS quation to Calculate Centifugal Acceleation Centifugal acceleation a(m/s ) π N l 3600 whee, N : otating spee (pm) l : Distance fom the cente to the cente of gavity of acceleation tansuce (m) Unit of Acceleation gal an Gavitational Acceleation g Belonging to CGS unit system, gal is a unit use to expess gavitational acceleation in gphysics, etc. It is tentatively appove to use in combination with the SI unit. gal cm/s 0 m/s Stana gavitational acceleation g m/s Countemeasue if Initial Balance ( Balance) Cannot Be Taken When boning a stain gage to a cuve suface o when using a semiconucto gage poviing a wie esistance ange, initial balance may not be taken occasionally. As an emegency countemeasue against such the case, thee is a paallel esistance metho escibe below. Inset the following paallel esistance p into the bige: p =. g / g whee, g : esistance of stain gage : Nominal esistance of bige(0ω o 350Ω) The sie of the bige to which the paallel esistance is insete is the opposite sie of the stain gage if g is lage than, meanwhile the ajacent sie if g is smalle than. In the case of 0 Ω esistance Diffeence fom (+Ω) 0.6 p (kω) Gaph to Obtain Powe/Wok, otating Spee an Toque Powe/Wok (kw) xample (A) : Toque is 59 N.m when powe an otating spee ae 500 kw an 3000 pm, espectively. xample (B) : Powe is 0.9 kw when toque an otating spee ae 00 N.m an 000 pm, espectively (A) (B) (B) (A) Toque (N. m) otating Spee (pm) 00 Paallel esistance Inseting Sie If g > g p g If g < p elational xpession of Toque, Powe/Wok an otating spee P πtn 60 whee, T : Toque (N. m) P : Powe o wok (W) N : otating spee (pm) xample of a DB-0A bige box g p g p 3 3 Pecaution : Avoi inseting p to the sie whee the stain gage is connecte. Such connection avesely affects the sensitivity. 9-3

15 9- elation between Tansuce output signals in Stain an Voltage The output of a stain gage tansuce is expesse in eithe stain (μm/m) o voltage (mv/v o μ/ V; voltage pe V bige excitation. The stain quantity,, an output voltage, e, have the following elation : e Ks whee, Ks: Gage facto of stain gage : xcitation voltage e Ks Suppose the gage facto, Ks, is.00. Then, e, an if ( V ), e Thus, the stain output an voltage output always have a elation of :. e.g..5 mv/v = 500 μv/v 3000 μm/m Convesion of Stain Quantity (Voltage) Measue by Tansuce into Pope Physical Quantity Stain quantity (o voltage) measue by a tansuce such as loa cell o pessue tansuce is convete into the physical quantity in pope engineeing unit as follows. The following types of calibation coefficients ae state in Kyowa's Test Data Sheet. Use a pope one fo the applie measuing instument. A : Calibation coefficient inicating the physical quantity coesponing to a efeence equivalent stain of μm/m B : Calibation coefficient inicating the physical quantity coesponing to an output voltage of μv against a bige excitation voltage of V. When using a stain amplifie physical quantity = Measue stain (μm/m) x A When using an amplifie othe than stain amplifie o ecoe Bige output voltage (μv) physical quantity = x B Bige excitation voltage (V) Connection to Calculate Aveage Output Voltage of the Same Moel Tansuces If multiple same moel tansuces ae connecte in paallel, thei aveage output voltage, e, can be calculate by the following equation. Also, output esistances of each tansuce ae equal. eeen Aveage output voltage e n whee, e, e,... en : Output voltage of each tansuce Avantages of emote-sensing Metho In measuement with the highly-accuate tansuce connecte by a long extension cable, cable conucto esistance an ambient tempeatue change cause measuement eos. The emote-sensing function emoves these factos causing eos an stabilizes the excitation voltage. i Cable esistance If, fo example, the 0.5 mm -conucto cabtye cable is extene by 00 m, the conucto esistance is appoximately.0 Ω. If the cable esistance in Fig. is.0 Ω, the ecipocating esistance on the input cicuit is 8.0 Ω. Suppose input an output esistances ae 350 Ω, then the voltage at both ens of the bige is: V whee, : Supply voltage (V) i Since thee exists a elation of e0 Ks, the sensitivity of the tansuce lowes by appoximately.%. Futhemoe, if ambient tempeatue changes by 0 uing measuement, voltages at both ens of a tansuce fluctuates by about 0.% an accuacy of tansuce even 0.0%O is euce. As shown in Fig., the emote-sensing metho has one aitional pai of cable fo etecting eos esulting in 6-conuctos. In the emote-sensing metho, although excitation voltage is lowee by cable esistances, this lowee voltage is leae by etecting wies to an eo amplifie an then be compae to stana voltage. This iffeent voltage is amplifie by an eo amplifie with high-amplification an high-impeance. Then, this voltage output ives a contol cicuit. As a esult, input voltage to bige is kept constantly without effects of cable esistances, leaing to accuate an stable measuements. In this case of emote-sensing metho, connections an conucto colos ae shown in Fig.. B White Fig. e o TCHNICAL NOTS e e A e F Yellow G Blue C Black D Geen Cable esistance e n Contol cicuit o amplifie ef. volt. Fig. DC bige excitation 9-

16 9-5 TCHNICAL NOTS Installation of Loa Cells to Hoppes o Tanks Usually, it is esiable that a total weight incluing the tae of hoppe o tank is evenly loae onto each loa cell. If the loaing point moves an the centoi is not fixe, estimate the locus of the centoi an efeing to the typical position, aange each loa cell so that a maximum loa is evenly applie on each loa cell. Thee may be two installation methos: stana an simplifie. With the stana metho, a loa is wholly eceive by only all loa cells. With the simplifie metho, a loa is eceive by combinations of loa cells, ummies, pivots an hinges. Geneal installation methos of hoppes an tanks ae shown in the below table. Featues of Stana Metho Loa cells eceive the whole loa, theeby enabling measuement with minimal effect of fluctuation of the centoi. Applicable to most substances: soli, powe, o liqui. Measuement accuacy eceives minimal effect of extenal factos such as tempeatue, vibation an installation conitions. Accuacy of loa cells is fully utilize. Featues of Simplifie Metho easonable pice ue to ummies an hinges. Applicable to only liqui substances. Difficult to be use in special types of hoppes an tanks an inapplicable to tanks an hoppes which centois move. Hinges shoul be installe caefully. Subject to avese effects of vibation an tempeatue. Type Hoizontal Vetical Cyline Squaeshape Special -point Hanging -point Hanging 3-point Hanging Shape Stana Metho Loa Cells Check os 6 to to 8 8 to 6 to Simplifie Metho Loa Cells Dummies Check os Typical Installations of Loa Cell Vetically Cylinical Tank As a ule, the simplifie metho is not applicable fo special type of hoppes o tanks -point Hanging Loa Cell Loa Cell Check o Movable Sale Loa Cell Sale Check o Check o Hoizontal Tank Ball Joint Loa Cell Compession Loa Cell otating Attachment Ball Joint Check o Movable Sale Loa Cell Sale Check o Tank 9-5

17 Output (B) 9-6 How to Obtain Pope ate Capacity of Loa Cells If the weighing object is a low-viscosity liqui showing less hoizontal movement with both the tae an content an initiating less impact, ate Capacity L HF. n whee, H: stimate weight of subject liqui F: Tae n: Numbe of loa cells If thee is vibation, use a highe facto in a ange of. to.5 accoing to the egee of acceleation. If the weighing object is powe o high-viscosity liqui, incease the above-mentione facto to.3. If thee is vibation, use a highe facto in a ange of.3 to.5. If the weighing object shows less hoizontal movement with both the content an tae but initiates lage impact, ate Capacity L SF n.3 whee, S: Maximum impact loa If the weighing object shows hoizontal movement with both the content an tae an initiates lage impact, ate Capacity L SF n.3 Incease the facto to.7 if impact is epeately applie. quations above ae on the supposition that the loa is evenly allotte to all loa cells use in a multiple numbe. If the loa is unevenly allotte, etemine the ate capacity consieing the loa given to the loa cell to which the biggest buen is allotte. In the case of a hanging application, it is ecommene to select a ate capacity times highe than obtaine by equations above, to ensue safe opeation. How to Obtain Accuacy of Loa Cell-base Weighing System To obtain the accuacy of an electonic loa cell-base weighing system, loa cell installation quality an eos ue to vibation, etc. shoul be consiee togethe with iniviual eos of loa cells an amplifies an ambient tempeatue change. Hee, we simplify to explain the metho of calculating the system accuacy by taking the case whee static eos of loa cell an amplifie ae main factos affecting the system accuacy. Obtain the accuacy of the etecting system incluing the loa cell an the accuacy of the amplifie. Then, obtain the system accuacy by calculating the squae oot of the sum of thei squaes. System accuacy i whee, : Accuacy of etecting section i: Accuacy of amplifie Geneally, the accuacy of the etecting system is obtaine by the following equation: 3 t 5 t whee, : Nonlineaity : Hysteesis 3: epeatability : Tempeatue effect on zeo balance (pe C) 5: Tempeatue effect on output (pe C) t: Change of ambient tempeatue If multiple loa cells ae use, n n whee, n: Numbe of loa cells Geneally, the accuacy of the amplifie is obtaine by the following equation : i ( t ) (3 t) 5 whee, : Nonlineaity : Tempeatue effect on zeo balance (pe C) 3: Tempeatue effect on sensitivity (pe C) : Aging effect on zeo balance 5: Aging effect on sensitivity Diffeence between Stain Amplifies an Signal Conitiones Amplifies fo measuement of ynamic vaiables ae available in types: AC bige excitation an DC bige xcitation. In Kyowa, amplifies using AC bige excitation is calle Stain Amplifies an amplifies using DC bige excitation, Signal Conitiones. Since the stain amplifies have the bige cicuit affecte by capacitive components, both esistive an capacitive components shoul be balance at the initial ajustment. In aition, the AC fequency of the bige excitation limits the fequency esponse to lowe than the DC system. But the AC bige excitation system povies highe sensitivity an is highly esistant against extenal noise, theeby making stain amplifies excellent in SN atio an zeo stability an fee fom themoelectomotive foce. Thus, stain amplifies ae most fequently use fo stain measuement with stain gages. Futhemoe, cuent stain amplifies aopt the CST metho, which automatically balances capacitive components an equies no ajustment by the opeato fo impove opeational efficiency. The signal conitiones using DC bige xcitation equies balance of esistive components only at the initial ajustment an povie highe fequency esponse but SN atio an stability ae infeio to the stain amplifies. But the DC bige excitation system povies highe output voltage than the AC bige excitation system, an thus signal conitiones ae fequently use fo measuement with stain gage tansuces AC type (DPM-93B) k 0k esponse Fequency (Hz) DC type (CDV/ CDA-900A) 500k Diffeence between Constant Voltage System an Constant Cuent System in Bige xcitation Signal conitiones using DC bige excitation ae available in types: CDV seies having the bige cicuit excite on constant voltage an CDA seies having the bige cicuit excite on constant cuent. Geneally, the constant voltage system is use but if the cable is extene between the signal conitione an stain gage tansuce, the cable esistance lowes the voltage to be applie to the tansuce, theeby esulting in ecease sensitivity (appox. 6%/00 m, 0 Ω). On the contay, the constant cuent system can keep the cuent constant against incease cable esistance, an thus the voltage applie to the tansuce is always constant an emains unaffecte by cable extension. With the constant cuent system, howeve, the bige esistance shoul be compensate if it iffes fom the nominal bige esistance. Tue value = Nominal bige esistance x Measue value Actual bige esistance Sensitivity eceasing atio (%) CDA-900A,CDV-900A (emote sensing) CDV-900A (350 Ω tansuce) CDV-900A (0 Ω tansuce) Length (m) of -conucto (0.5 mm ) shiele cable Note that the CDV-900A has a built-in emote-sensing cicuit, an thus use of a 6-conucto (0.5 mm ) shiele cable pevents the sensitivity fom eceasing up to appoximately km. Fo the emote-sensing metho, efe to page 9-3. TCHNICAL NOTS 9-6

18 9-7 TCHNICAL NOTS Pinciple of CST Metho The CST (Capacitance Self Tacking) metho is the Kyowa evelope metho of electically canceling any unbalance capacitance constantly uing measuement with the stain amplifie of AC bige excitation system, automatically with no switch opeation mae. As shown in the block iagam below, the unbalance capacitance etecte by the C etecting cicuit is invete in phase by the ive an negation cicuits. The invete capacitance is ae to the bige output to negate the unbalance capacitance. This metho not only eliminates the nee fo toublesome initial ajustment of unbalance capacitance of stain amplifies using AC bige excitation system but also cancels any unbalance capacitance uing measuement to solve the poblem on unstable measuement ue to unbalance capacitance. It also enables use of highe-fequency AC bige excitation an evelopment of stain amplifies featuing a fequency esponse at a maximum 0 khz. Pesently, all Kyowa stain amplifies of AC bige excitation system aopt the CST metho. Balance Cicuit Bige Powe Cicuit Negation Cicuit Caie Amplifie Cicuit Dive Cicuit Detecting Cicuit C Detecting Cicuit DC Amp Cicuit (Filte) 90 Phase Cicuit Oscillato Cicuit Output eason Why Constant Cuent Bige xcitation is use fo Civil ngineeing Measuement with Cable xtene See Fig. at the ight an suppose that is the voltage of the bige excitation an ' is the voltage applie to the tansuce in the constant voltage bige excitation system. Then, ' I whee, I is the voltage ecease ue to cable esistance an I is that ue to the ecipocating cable esistance. If the cable is shot, 0, an thus, ' e Ks If the cable is extene, ' I e ' Ks Ks Consequently, the output voltage is lowee. The input of Fig. may be ewitten to Fig.. In Fig. ' e ' Ks g g, an thus, g This means an output ecease by g. g Ks g This means that extension cable esistance oes not cause any output ecease. Howeve, the input esistance, g, of the bige affects the output. But a iffeence between the nominal bige esistance of civil engineeing tansuce an its actual bige esistance is extemely small, an thus it nee not consie that the input esistance of the bige affects the accuacy. Civil ngineeing Tansuce I Compensation equation: e x g ' Fig. Nominal bige esistance g e = ' Ks ' g Fig. g: Bige esistance of tansuce : Cable esistance : Voltage of bige excitation I: Cuent of bige excitation ': Voltage applie to bige e: Output voltage Ks: Gage facto : Stain TDS TDS is the aconym of Tansuce lectonic Data Sheet, which is incopoate into tansuce. By eaing the electonic ata fom the tansuce, the measuing instument is automatically place in pope measuing conitions without manual ajustment. The fomat of the tansuce electonic ata witten in the sheet is povie in I 5.. The ata is oughly classifie into the following 3 types: Common ata: Tansuce ientification ata incluing the manufactue ientification coe, moel numbe coe an seial numbe. Template: Tansuce pefomance ata incluing the type of tansuce, etecting physical vaiable, ate capacity, ate output, input esistance, ecommene excitation voltage, ate of calibation. Note: Fo tansuces poviing both positive an negative output signals an aveage of both output signals is witten as the ate output. Use ata: Fo maintenance an sevices by Kyowa enginees. The ata is patially open to uses an up to 3 alphanumeic chaactes can be witten on the sheet by uses. Howeve, a eicate witing evice is equie. Inquiies ae welcome. With the constant cuent system, the cuent, I, is constant at all times, an thus the bige output eceives no influence fom. bige excitation 'Ig e Ig Ks 9-7