Operation Manual for Force Sensors
Contents
1. LORENZ MESSTECHNIK GmbH 3555 sion Fax ort7e 9790 2 Operation Manual for Force Sensors E Mail info lorenz sensors com Technical changes reserved 090273 doc Internet www lorenz sensors com Page 1 of 14 LORENZ MESSTECHNIK GmbH 3555 sion Fax ort72 1937902 Imprint Manufacturer Place Lorenz Messtechnik GmbH D 73553 Alfdorf 2007 Lorenz Messtechnik GmbH Alfdorf Reprint Interdiction Reprint even in extracts only with written authorization Modification Technical changes reserved References in this Text 1 6 Warning Notes Page 4 Attention must be paid to the accident prevention regulations of the trade associations During operation the safety precautions must be operative 5 1 General Requirements Page 7 Caution During the assembly inadmissibly large forces may not act on the sensor At small nominal forces lt 100 N connect the sensor electrically during the assembly and observe the signal the measurement signal may not exceed the limit values 5 2 4 Fix Assembly Page 8 The assembly without balancing elements is problematic for the operating safety 7 1 Engaging Page 11 The warming up period of the force sensor is approx 5 min 7 3 2 Natural Resonances Page 11 An operation of the device in natural resonance can lead to permanent damages E Mail info lorenz sensors com Technical changes reserved 090273 doc Internet www lorenz sensors com Page 2 of 14 LORENZ MESSTECHNIK GmbH2. 2 3 JOMEEYOS ci a a eh ek Ea A eee apes ethene E eee ee 8 5 2 4 FASS CMMI Vida colada cines 8 5 3 Overload Protection esane Sec tenet cic Seth cn ace sated sce teratat e a a A EEA 8 5 3 1 ALE TO LU Lalo 1 y OPEP OU N PO O n e doce Eaa eea E E aaa EE EEE Ee nE EEN EEE 8 5 3 2 simple Overload Protection da a a nie ere 9 5 3 3 Measuring Path MagnificatiON oooconnnccnnnoccconncccnnnarcncnnnncnr none 9 6 Electrical COmectiON auciaanccia ir da pda 10 6 1 Pin COnNNECHON cistitis 10 6 2 Free Gable Ends viii d 10 6 3 Ele A A fegdetecessdacaedeud lacs E A E E A E 10 6 4 Shielding CONNECtiON ocooncccnncconncononccnnocnanccnn na norcn corran crac 10 6 5 Extension Cables contatti tal ioialis 10 6 6 Running of Measuring Cables coococncccinncccncccnoncnnoncnnnncononcnnnncnnnn cn nnn cnn nc nr c arena 11 TL MeasulINQ ui di 11 7 1 EMG AGING ea 11 7 2 Static Quasi Static Forces c ooooconnccincconocnonccnnonanoncnnn nn crac rra rra 11 7 3 DYMaIMIC FORCES cuerno lid N T ed ia 11 7 3 1 AAA PX E E E ecient 11 7 3 2 Natural RESONANCES ziti ccivscecchebeeelAEs cegekernadede lees Saab aaea Seta dla 11 7 4 Biierger elo sr S E E E A E EE 11 7 4 1 TemperatUr soies nrinn erines ea ara aen paip aie a ri ieee eiiean ine iaria 11 7 4 2 O E E E E E AN 12 7 4 3 ce E E T 12 7 4 4 RadiDaCtV Victor ET 12 7 4 5 Macul surte aia daa esla done bona 12 7 4 6 Mechanical Disturbance Sorose roseis ici iaa todas 12 7 4 7 EME t n 12 7 5 Calibration Contro
3. measurement layout Mechanic at minimum these spring constants must be ld spong paris considered ofthe sensor Introduction ofthe contact faces parts ofthe introduction parts Contact Sensor Contact Introduction parts Introduction face 5 3 2 Simple Overload Protection Caution Normally the measuring path is very small For a simple overload protection a dead stop grinded to the corresponding dimension can be manufactured All parts must be grinded and hardened Accurate alignment of the faces is necessary Force sensor Path for dead stop Path for dead stop Measuring path at nominal force 1 1 Dead stops Path for dead stop Overload protection for bending beam large measuring path Dead stop Sensor 5 3 3 Measuring Path Magnification The path for the dead stop gets magnified by a spring Path for dead stop Spring pre stressed to Dead stop nominal force Dead stop screws annsan Spring lexible The path for dead stop is determined by the spring Dead stop Disadvantage large measuring path and the sensor must be lead axially By the spring being pre stressed to nominal force plate washer package a higher stiffness is achieved in the nominal range Above the preload the spring gets soft and a larger measuring path is achieved E Mail info lorenz sensors com Technical changes reserved 090273 doc Internet www lorenz sensors com Page 9 of 14 LOREN
4. s 0 1 mm gt Es Fs E A i gt F E s 0 5 kg m s 0 0001m 5000 kg m s 5000 N Weight force m g with g local acceleration of fall Demonstration in resting state E Mail info lorenz sensors com Technical changes reserved 090273 doc Internet www lorenz sensors com Page 6 of 14 LORENZ MESSTECHNIK GmbH Pes hio Pona 5 Mechanical Assembly 5 1 General Requirements Requirements of the bearing surface and the force introduction faces Surfaces hardened to HRC 50 grinded and or lapped roughness Rz 4 evenness 0 02 mm At possible overload an overload protection should be considered For calibration the sensor must be easily demountable Assembly The base frame of the force sensor must show a preferably plane mounting surface evenness 0 02 mm The base frame must be free from dirt grease and dust Do not overload the sensor during the assembly Even a short term overload can damage the sensor Preferably use dummies for the alignment of the mechanic introduction parts The force introduction must be carried out punctiform The load conduct the force introduction components and the force sensor must be connected to each other rigidly and free from backlash The lead in forces should always act on the force sensor in the sensor specific direction of measurement see data sheet By this the applied load and the force sensor form a continu ous line of action Loading the sensor with sh
5. 925 Senos ist 3071721087300 Contents 1 A NN 4 1 1 Safety and Caution Symbols oooooconnccnnnccnncccnnonanoncnononn canon cnn r ancora 4 1 2 ME RA A O 4 1 3 DA ia 4 1 3 1 Neglecting of Safety NOTES oooonooccccconocicconccononcnoncconencnnnnconencnnnncnnn cn nn cnn n cnn aran n erodi eie eaaa inisi 4 1 3 2 Remaining DIES nica iaa 4 1 4 Reconstructions and Modifications ooonocccononicccnnoncccnnnannnonann non nnon cnn nnnn nr anea eaa ideea aneia 4 15 Personnaliser oon a ea aE E E a then ee a aot Ni ee ee ETE it 4 1 6 Warning Notes a E E EN 4 2 Termi DefiMtionS cd 5 2 1 DIrECION O FOCE srera E E EEE E E E 5 2 2 SPN CONSAN secre ac eea e e a a a a a a a 5 3 Product Descriptio sossen E ene hee pice eet 5 3 1 Mechanical AA atic cpidieacucedaitl a EA A EEE E EE RER E 5 3 2 Electrical S tup ecceeseeseseeeeseeeeneeseaeeeeseeeeaeeeeaeeseaeeceaeesaeeseaeesaeeseaeesaeeseaeeseaeeseaeeseaeeseaeeseaeeseaeeseaeeseeeseaeeees 6 4 Gonstruction and DESION utaciicacrlana Sate hd ned cascade detec Din rain d a aia 6 4 1 Calculation Example for an Accelerated Mass ooocconcccincccinniniccccnonnnoncncnonnnnnn cronica 6 5 Mechanical Assembly cenie eeo ao 7 5 1 General RequirementS coooconcconnnnnncconncnnncncnccnnn nro 7 5 2 Urner NotES cicivcior nena it ide et seteetaasbdecfenneasiauectiecgebdadaentd A 7 5 2 1 ACOH ACC eas cad teh cect enced O A E A E E A AE E O 7 5 2 2 Face CONVEX OP CI yoceesaaver bua sea A R aE R EEEO EE EE 8 5
6. E Faces always plane preferably grinded Minimize angular errors Sensor must bear on the complete face Y 5 2 3 Joint Eyes Avoid lateral forces at tension force sensors gt Balance of axial offset gt Force introduction in axial direction gt Not suitable for compression forces N cs E Acting Force 5 2 4 Fix Assembly CS The assembly without balancing elements is problem atic for the operating safety gt The introduction must occur free of lateral forces Torque may not arise in the sensor The introduction faces must be parallel to each other axial force introduction The temperature elongation of the parts must be considered The effect can not be planned i 5 3 Overload Protection 5 3 1 Measuring Path Estimate of the measuring path of the sensor Double bending beam Shear force Membrane Compression cylinder 4 4 J gt 0 01 0 1 1 Measurement range in mm Typical values of the measuring path at force sensors Further must be considered Contact stiffness stiffness of the transit of the introduction part to the sensor Stiffness of the introduction parts etc E Mail info lorenz sensors com Technical changes reserved 090273 doc Internet www lorenz sensors com Page 8 of 14 Obere SchloBstr 131 07172 93730 0 LORENZ MESS TE CHNIK GmbH 73553 Alfdorf Fax 07172 93730 22 Example for the estimate of the complete spring stiffness of a force
7. ESSTECHNIK GmbH 3555 sion Faxo7tio 9790 2 11 Disposal The force sensors must be disposed according to the valid provisions of law For this see our General Terms and Conditions www lorenz sensors com 12 Calibration At the time of delivery force sensors have been adjusted and tested with traceable calibrated measuring equipment at factory side Optionally a calibration of the sensors can be carried out 12 1 Proprietary Calibration Acquisition of measurement points and issuing a calibration protocol Traceable calibrated measuring equipment is being used for the calibration The sensor data are being checked during this calibration 12 2 DKD Calibration The calibration of the sensor is carried out according to the guidelines of the DKD At this calibration the uncertainty of measurement of the force measuring instrument is determined Further information can be obtained from the Deutscher Kalibrierdienst http www dkd eu 12 3 Re Calibration The recalibration of the force sensor should be carried out after 26 months at the latest Shorter intervals are appropriate at e Overload of the sensor After repair After inappropriate handling Demand of high quality standards Special traceability requirements 13 Data Sheet See www lorenz sensors com 14 Literature Dubbel Taschenbuch f r den Maschinenbau Springer Verlag E Mail info lorenz sensors com Technical changes reserved 090273 doc Internet www lorenz
8. Z MESSTECHNIK GmbH Pisa Faena 6 Electrical Connection 6 1 Pin Connection Schirm shield 6 pin Function 1 Excitation Excitation Shield Signal 2 3 4 Signal 5 6 100 Calibration Control Option 6 2 Free Cable Ends Wire Function green Excitation brown Excitation yellow Signal white Signal 100 Calibration Control grey Option netting Shield 6 3 Cables Only use a shielded cables with preferably small capacity We recommend measuring cables from our product range They have been tested in combination with our sensors and meet the metrological re quirements 6 4 Shielding Connection In combination with the sensor and the external electronics the shield forms a Faraday Cage By this electro magnetic disturbances do not have any influence on the measurement signal At potential differ ence problems we recommend to ground the sensor 6 5 Extension Cables Caution depending on bridge resistance and wire cross section the measuring cable length enters into the characteristic value of the sensor Therefore order the sensor together with the extension cable and the calibration at Lorenz Messtechnik GmbH Dependence of the characteristic value from the cable length Wire cross Cable resistance Deviation per m Deviation per m Deviation per m section perm cable length a
9. al has dropouts Cable defect e Repair cable Zero point outside of tolerance Cable defect e Repair cable Sensor mounted distorted e Mount correctly Strong lateral forces e Minimize shearing forces Sensor overloaded e Send sensor to manufacturer Wrong display indication Calibration not correct e Re calibrate Sensor defect e Repair by manufacturer Force shunt e Eliminate shunt 9 Decommission All sensors must be dismantled professionally Do not strike sensor housings with tools Do not apply bending moments on the sensor e g through levers 10 Transportation and Storage The transportation of the sensors must occur in suitable packing For smaller sensors stable cartons which are well padded are sufficient e g air cushion film epoxy crisps paper shavings The sensor should be tidily packed into film so that no packing material can reach into the sensor ball bearings Larger sensors should be packed in cases 10 1 Transportation Only release well packed sensors for transportation The sensor should not be able to move back and forth in the packing The sensors must be protected from moisture gt Only use suitable means of transportation 10 2 Storage The storage of the sensors must occur in dry dust free rooms only Slightly lubricate rust sensitive parts with oil before storing E Mail info lorenz sensors com Technical changes reserved 090273 doc Internet www lorenz sensors com Page 13 of 14 LORENZ M
10. earing forces lateral forces and torque must be absolutely avoided even small shearing forces can generate larger uncertainties of measurement In addition the spring body depending on the measuring range can be plastically deformed At flexible mounting positions especially pendulous assembly in tension direction we recom mend the joint balls listed on the data sheet for the force introduction Force shunts cables hoses pipes etc must be avoided ES Caution During the assembly inadmissibly large forces may not act on the sensor At small nominal forces lt 100 N connect the sensor electrically during the assembly and observe the signal the measurement signal may not exceed the limit values Force Direction Measuring Direction of the Sensor Geometric Axis Always treat the sensor with care 5 2 Further Notes 5 2 1 Face Face Wrong Acting Force 4 Measuring Axes of the Force Sensor Faces always plane preferably grinded Faces always parallel to each other Force introduction always measuring axis E Mail info lorenz sensors com Technical changes reserved 090273 doc Internet www lorenz sensors com Page 7 of 14 LORENZ MESSTECHNIK GmbH 3555 sion Fax ort7e 1937902 5 2 2 Face Convex The convex introduction balances small angular deviations of the introduction levels Error 1 cos q zea e g a 1 8 gt Error related to the final value 0 05 A AA
11. ection of Force Compression Force Tension Force Tension and Compression Force Positive Output Signal Positive Output Signal Positive Output Signal Positive Output Signal Compression Force Sensor gt Compression Force Tension Force Sensor gt Tension Force Tension and Compression Force Sensor gt Tension Force Compression and Tension Force Sensor gt Compression Force Ib Ib I gt IP F 2 2 Spring Constant Under compression force F the measuring body is jolted by the I amount 4 l Al The spring constant is calculated according F d Spring constant c of a sensor c A d Ad 3 Product Description The sensor measures static and dynamic forces The mounting position of the force sensor is horizontal or vertical 3 1 Mechanical Setup The force sensor consists of a measuring body and a housing By the introduced force mechanical tensions occur in the measuring body which are measured by strain gauges SG Since the obtained measuring signal is very small the SG are interconnected to a full bridge By the bridge connection the temperature compensation is obtained as well There are following types of force sensors 4 Tension Rod Bending Beam Bending Beam Shear Force E Mail info lorenz sensors com Technical changes reserved 090273 doc Internet www lorenz sensors com Page 5 of 14 LORENZ MESSTECHNIK GmbH 3555 sion Fax ort7e 1937902 3 2 Electrical Se
12. force is a slowly changing force The calibration of the sensors occurs statically on a calibration device The applied force may accept any value up to the nominal force 7 3 Dynamic Forces 7 3 1 General The static calibration procedure of force sensors is also valid for dynamic applications Note The frequency of force must be smaller than the natural frequency of the mechanical measurement setup The band width must be limited to 70 of the nominal force 7 3 2 Natural Resonances The force sensor with its assembly parts forms a mechanical oscillator The resulting natural resonance of the layout can be estimated according following formula f natural resonance f A 1000 e c spring constant in N mm 2m m m mass in kg estimated spring constant c from nominal force measured path see 5 3 1 Measuring Path Moa i The damping d of the oscillator can be ignored for a simple estimate E Operation of the device in natural resonance can lead to permanent damages 7 4 Disturbance Variables 7 4 1 Temperature Radiant heat gt Higher temperatures than expected shielding Temperature gradient gt Error in temperature compensation Fast temperature changes often lead to temperature gradients E Mail info lorenz sensors com Technical changes reserved 090273 doc Internet www lorenz sensors com Page 11 of 14 LORENZ MESSTECHNIK GmbH Sas Aion Faxo7tio 3790 2 7 4 2 Humidity e Normal air humidity
13. l Option vivia EEEE bedi E EN ENER 12 8 MAINTE MANGE uta dt di pula 13 8 1 EME AAEE EA EAA EAA EASE EA EAA EASEEAEEA Enne enne enetan enaena 13 8 2 SS ee E E E E E A errr ts 13 9 IDECOMUMISSION visi 13 10 MEUS tett tttn titus tast AA ttnn EASEEACEAAEEAAEAn EASE EAEnatEnntnaenn ennnen nenene 13 10 1 Transport 13 10 2 SU A O 13 11 DISPOS lic A ta 14 12 Calibre iia 14 12 1 Proprietary Calibration ooooonnnccnnnnnnnnnnccnnnconocccnnccnnancn ronca r arc rn narrar 14 12 2 1D DE r 0 1 1 0 ee eee 14 12 3 RRE G ANID TALON sieren aeea ere e ede e e ites e e a eane ee a e E e 14 13 Dala Sh berrera ia e E E aE Ea eE Oa ERE E EEAS EEEa E ORERE TENE EEA 14 14 LOTTO Aa E E E E A E ia 14 E Mail info lorenz sensors com Technical changes reserved 090273 doc Internet www lorenz sensors com Page 3 of 14 LORENZ MESSTECHNIK GmbH 3555 igor Paxo7t92 9310 22 1 Read First 1 1 Safety and Caution Symbols Caution Injury Risk for Persons Damage of the Device is possible CS Note Important points to be considered 1 2 Intended Use Force sensors are intended for the measurement of forces in test benches assembly force appliances presses and testing machines This measurand is suitable for control and regulation tasks The valid safety regulations must be absolutely respected The force sensors are not safety components in the sense of the intended use The sensors need to be transported and stored appropriately The assembly commi
14. nt the zero point and the nominal value can be checked Function By applying positive SG supply the measuring Excitation bridge is electrically detuned so that at the output a measuring signal of 100 of the nominal value is available Optionally 50 80 possible Sensor External gt Only use calibration control at unloaded condition of the force sensor E Mail info lorenz sensors com Technical changes reserved 090273 doc Internet www lorenz sensors com Page 12 of 14 LORENZ MESSTECHNIK GmbH 325 aoa Bacortrs 3730 22 8 Maintenance 8 1 Maintenance Schedule Action Frequency Date Date Date Control of cables and connectors 1x p a Calibration lt 26 months Control of fixation flanges shafts 1X p a 8 2 Trouble Shooting This chart is used for searching for the most frequent errors and their elimination Problem Possible Cause Trouble Shooting No signal No sensor supply e Outside of permissible range e Connect supply e Cable defect e No mains supply Signal output connected wrong e Connect output correctly e Evaluation electronics defect Sensor does not react to force Sensor not mounted properly e Mount properly No power supply e Outside of permissible range e Connect supply e Cable defect e No mains supply Cable defect e Repair cable Connector connected wrong e Connect properly Force shunt e Eliminate shunt Sign
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16. ssioning and disassembling must take place professionally 1 3 Dangers The force sensor is fail safe and corresponds to the state of technology 1 3 1 Neglecting of Safety Notes At inappropriate use remaining dangers can emerge e g by untrained personnel The operation manual must be read and understood by each person entrusted with the assembly maintenance repair opera tion and disassembly of the force sensor 1 3 2 Remaining Dangers The plant designer the supplier as well as the operator must plan realize and take responsibility of safety related interests for the sensor Remaining dangers must be minimized Remaining dangers of the force measurement technique must be pointed out 1 4 Reconstructions and Modifications Each modification of the sensors without our written approval excludes liability on our part 1 5 Personnel The installation assembly commissioning operation and the disassembly must be carried out by quali fied personnel only The personnel must have the knowledge and make use of the legal regulations and safety instructions 1 6 Warning Notes Attention must be paid to the accident prevention regulations of the trade associations During operation the safety precautions must be operative E Mail info lorenz sensors com Technical changes reserved 090273 doc Internet www lorenz sensors com Page 4 of 14 LORENZ MESSTECHNIK GmbH 92g oenossicisr 07172 957300 2 Term Definitions 2 1 Dir
17. t cable length at cable length at bridge resistance bridge resistance bridge resistance 350 Q 700 Q 1000 Q 0 14 mm 2 0 28 Q 0 08 0 04 0 028 0 25 mm 0 162 0 046 0 023 0 016 0 34 mm 0 122 0 034 0 017 0 012 Cable resistance 2 x resistance of the cable length both feeder lines of the sensor The sensors with the ordered cable length are calibrated at Lorenz Messtechnik GmbH Therefore the cable length does not need to be considered in this case E Mail info lorenz sensors com Internet www lorenz sensors com Technical changes reserved 090273 doc Page 10 of 14 LORENZ MESSTECHNIK GmbH 3555 sion Fax ort 72 9790 2 6 6 Running of Measuring Cables Do not run measuring cables together with control or heavy current cables Always assure that a large distance is kept to engines transformers and contactors because their stray fields can lead to interfer ences of the measuring signals If troubles occur through the measuring cable we recommend to run the cable in a grounded steel con duit The space requirement for the connection cable must be considered during the mechnical design The connection cable may not be lead out stiffly 7 Measuring 7 1 Engaging The warming up period of the torque sensor is approx 5 min Afterwards the measurement can be started ES The warming up period of the torque sensor is approx 5 min 7 2 Static Quasi Static Forces Static and or quasi static
18. tup Excitation The SG Full Bridge is led out directly to the connector or the cable Optionally a control was inserted For this the SG Full Bridge gets detuned in such a way that at the output a measuring signal can be measured which corresponds a to the nominal force Signal External Switch Sensor i External 4 Construction and Design Please clarify following points at the beginning of the construction Required space for the connection cable For equipment monitoring calibration the sensor must be easily demountable If necessary provide a dummy for assembly and test runs Consider required space for overload protection Consider requirements of the force introduction faces Determine maximum load accelerated masses generate forces as well Dynamic characteristics of the setup Ambient conditions Temperature gradients Impact of temperature changes to the setup For further indications see chapter Assembly e Consider electrical measuring devices for test and trouble shooting as well 4 1 Calculation Example for an Accelerated Mass Example Mass m falls on a plate with celerity v by this force peaks emerge acceleration deceleration v Kinetic energy of the mass E Y mv Demonstration shortly before the collision F Brake energy Esg F s S The brake distance s must be estimated Example Demonstration of max brake force v 1 m s 3 6 km h m 1 kg gt E 0 5 kg m s braking
19. up to 90 rel air humidity has no influence on material e The sensors are not sea water resistant 7 4 3 Gases Aggressive Gases can damage cables materials and strain gauge bridges 7 4 4 Radioactivity Influence on material and strain gauges has not been tested by us and can therefore not be recom mended 7 4 5 Vacuum At force sensors normally no problems are to be expected at Rough vacuum of 10 mbar up to 1 mbar e g for the vacuum packaging Fine vacuum of 1 mbar up 10 mbar e g for coating Problems due to outgassing of the force sensor materials have to be cleared from case to case at E f A ies High vacuum of 10 mbar up to 10 mbar e g for scientific research Ultra high vacuum of 10 mbar up to 10 mbar e g for scientific research 7 4 6 Mechanical Disturbances Measured values falsifications can occur by following disturbance variables Torsion Bending Minimize and or avoid disturbance variables e Radial load Vibrations gt Minimize by decoupling of oscillation 7 4 7 EMC e Electrical disturbances e Magnetic disturbances e EMC electro magnetic disturbances welding equipment etc Avoid these disturbance variables by covers shieldings etc 7 5 Calibration Control Option Excitation By acontrol resistance a signal is generated in the sensor which corresponds to the nominal value of the sensor External Switch Advantages Re Calibrations are reduced Before each measureme
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