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1. bae eee Rn kb 64 Damian Frey High Temperature Tribometer Simon W est 69 69
2. X y 2 Ill 20 Characteristic frequencies on the oven tube It is advisable to avoid running experiments with continuous operation with motor speeds around these characteristic frequencies As shown in the above diagrams the characteristic frequencies are e Between 450 and 550 rpm e Between 900 and 1250 rpm e Between 1750 and 1900 rpm e Between 2200 and 2450 rpm Damian Frey High Temperature Tribometer Simon W est 14 69 nc cs Materiais Scienco amp Technology 4 2 Electrics The most remarkable change in electrics is the supply for the motor The rotation speed is now controlled by the frequency converter instead of the manual gear The frequency converter is controlled with LabVIEW The Dahlander switch S2 defines the maximum speed of the motor It sets the motors windings either to a triangular or double star circuit max 1500 rpm 3000 rpm Due to the new principle of measurement the tribometer contains various additional sensors and other components The sensors power supply is an AC DC converter with 15VDC Some switches are not needed anymore or were replaced by the functionality of the LabVIEW implementation The interface terminal between the tribometer and the LabVIEW data acquisition card is placed in an aluminum box at the side of the tribometer Four D Sub jacks 15 poles connect the box with the corresponding electrical components of the tribometer The terminal is connec
3. o u S s k S Variable fmax fast mode motor fmax slow mode motor U max output V speed counts round incremental encoder Upper threshold fuse protection Lower threshold fuse protection Step fuse protection DAQ Card Temperature Card heating Current x A to control signal V Description The maximum frequency in Hz the motor can achieve if it runs in fast mode The maximum frequency in Hz the motor can achieve if 1t runs in slow mode The maximum output in Volt of the LabVIEW analog output The speed controller uses a PID controller and a linear function which sets the output in dependence of the speed to achieve This value is used to calculate the linear function in the speed controller The number of counts the incremental encoder delivers when the motor makes one complete turn When the current exceeds this value the maximum allowed heating current is reduced by step When the maximum allowed heating current was reduced and the current falls below this value the maximum allowed heating current is increased by step The maximum allowed heating current is decreased and increased by this value The LabVIEW device number of the data acquisition DAQ card The LabVIEW device number of the temperature measuring card To know how to the control signal in volts corresponds to a given heating current in ampere this formula is used The given current x is e
4. dynamic torque M U Ill 34 Characteristic curve high temperature dynamic torque When the tribometer is not loaded an idle torque can be measured which depends on the rotation speed To compensate the idle torque we used a logarithmic formula as shown in III 35 We repeated the experiment yellow line to evaluate the error red line of the compensation For a more accurate compensation some more idle torque measurements are necessary 8 2 0 6 0 5 0 4 0 3 0 2 torque M Nm 0 1 rotation speed rpm idle reference torque M Nm idle torque M error Nm idle torque M Nm Logarithmisch idle reference torque M Nm Ill 35 Idle torque compensation Damian Frey High Temperature Tribometer Simon W est 26 69 n Det Focbh chzehnls Horkeesteclesen EMPAQ Hoahestule f r Tashnik Materiais Science amp Technology 4 5 5 Room temperature measurement 4 5 5 1 Normal force Analog Input 0 high temperature normal force Due to the different geometries with the room temperature force module installed the strain gauges measuring bridge has another characteristic curve for the normal force The corresponding load of the output voltages carrier frequency amplifier are measured with the already calibrated room temperature force module and calculated with its characteristic linear function Carrier frequency amplifiers channel 3 settings for
5. 50 0 11 46 28 11 47 55 11 49 21 11 50 48 11 52 14 11 53 40 11 55 07 11 56 33 11 58 00 time sample temperature oven temperature Ill 60 Regulated oven temperature If the sample temperature is regulated the sample has at least the programmed temperature but the oven can be cooler than the programmed temperature regulated sample temperature 400 350 300 12 26 42 12 29 35 12 32 27 12 35 20 12 38 13 12 41 06 time sample temperature oven temperature Ill 61 Regulated sample temperature Damian Frey High Temperature Tribometer Simon W est 58 69 n TERTII EMPAQ AA Haahestule t r Technik Materiais Scienco amp Technology 7 Problems and their solutions 7 1 Shielding As we started measuring sensor signals with LabVIEW we realized that the standard shielding with earth wire potential did not shield the signals from transient disturbance We had to shield them with the LabVIEW ground potential Since the housings of the sensors are connected with their shield we had to shield it with an additional shield We stripped another cable with shield mounted the shield around the cables and connected them with LabVIEW ground potential To isolate the shield we mounted shrink tubing around it 7 2 Heating element and dimmer 7 2 1 Dimmer During the first experiments an unexpected damage of the dimmer occurred Since then it was not possible to con
6. Temperature Channel 14 Temperature Channel 15 Damian Frey Simon W est 20 69 High Temperature Tribometer n LE isse testo EMPAQ Hoahestule f r Technik Materiais Science amp Technology 4 5 Analog signal processing 4 5 1 Current measurement Analog Input 5 current phase R Analog Input 6 current phase S Analog Input 7 Current phase T Current is measured with three Hall sensors LEM HX 15 P characteristic curve I ITA 0 00 0 50 1 00 1 50 2 00 2 50 U V current I 15 4 U 3 00 3 50 4 00 4 50 Ill 28 Characteristic curve current Damian Frey Simon W est 21 69 High Temperature Tribometer ni Fachhoatrashuls Mordeesotector aia EMPAQ Hoahestule f r Tanh nik Materiais Science amp Technology 4 5 2 Rotation speed measurement Counter Input 1 rotation speed Rotation speed is measured with an incremental encoder 500 pulses per 360 characteristic curve n 0 5000 10000 15000 20000 25000 30000 impulses per second Hz rotation speed n 60 500 f Ill 29 Characteristic curve rotation speed Damian Frey High Temperature Tribometer Simon W est 22 69 n LU Fochhoshectinls Horlvzertecheyen Pa ME Hogheshule A Materi is Science amp Technolo Xy 4 5 3 Calibration of the force sensors To calibrate the force sensors we measure the output voltages of the carrier fr
7. Ill 57 Diagram with different sampling rates at 100ms saving rate Damian Frey High Temperature Tribometer Simon W est 56 69 n 4 Fachhochschule Nordvesctechven EMPAQ Hoahectule f r Tastanik Materiais Science amp Technology sampling rate 2ms 0 4 0 35 0 3 0 25 HO 0 2 0 15 0 1 0 05 0 200 400 600 800 1000 distance m sampling 2ms saving 500ms sampling 2ms saving 100ms Ill 58 Diagram with different saving rates at 2ms sampling rate sampling rate 100ms 0 200 400 600 800 1000 distance m sampling 100ms saving 100ms sampling 100ms saving 500ms Ill 59 Diagram with different saving rates at 100ms sampling rate Damian Frey High Temperature Tribometer Simon W est 57 69 n LE isse tese EMPAQ Hoahestule f r Tanh nik Materiais Science amp Technology 6 4 Regulation of oven or sample temperature The operator can choose between oven and sample temperature regulation The following temperature diagrams show the difference Programmed temperature 200 C programmed distance 500 m The sudden temperature rise is from the friction when the motor starts If the oven temperature is regulated the oven has at least the programmed temperature Due to the friction the sample is hotter than the programmed temperature regulated oven temperature 350 300 250 EE aah 200 T C 150 100
8. Variable Minor error port Major error port Default sending port Signal x V to torque Nm Correct the torque as a function of the rotation speed rpm Signal x V to Fn N Correct the normal force as a function of oven temperature Signal x V to Fn N with room temperature force module Signal x V to Fn2 N room temperature force module Signal x V to Ft2 N room temperature force module Signal x V to current A Description The port on the local computer on which the system listens for new minor errors which occurred on the remote computer The port on the local computer on which the system listens for new major errors which occurred on the remote computer The default port on the remote computer to which the local computer sends commands and configuration data e g start stop measuring This value is just the default value It has no effect on the remote computer The actual port to which the local computer sends commands needs to be configured when connecting to the remote computer The measured signal x in volts will be evaluated with this formula The result is interpreted as a torque with the real word unit Newton meter A torque can also be measured even when no load is applied This torque is a function of the motors frequency The software calculates with the frequency of the motor x in rounds per minutes and this formula a correction value This value is s
9. n MU oiim EMPAQ NA Hasheshula t r Tagh nik Materiais Scienco amp Technology 2 Introduction 2 1 Initial situation The Federal Institute for Material Science and Technology EMPA uses at its branch in Thun a device to determine the specific abrasion properties of two samples rubbing on each other In the experiments aring and a block are used for this tribometer test Firstly the parts are cleaned weighted and then installed in the machine The ring is turned at a given speed for a given time or distance while the block is pressed against the rotating ring The test chamber can be heated up to 700 C After the experiment the parts are cleaned and weighted again in order to determine the mass loss due to friction and consequent abrasion In a former diploma project realized by Martin Stettler of the University of Applied Science in Burgdorf an additional device has been developed and installed The device allows measuring the friction force as well as the normal force during an experiment This enables the user making a conclusion of the coefficient of friction The motor to rotate the probe is controlled on off by a LabVIEW application The data acquisition is also done using the same software which allows to print protocols and to export the data for further analysis e g MS Excel Unfortunately with the new device installed the oven cannot be heated up anymore For experiments with high temperature requireme
10. 2560W 4 5 7 2 Frequency converter control Analog Output 1 control input frequency converter The control input of the frequency converter 0 10VDC sets the frequency of the motor power supply 0 50Hz which determines the rotation speed 0 1500rpm or 0 3000rpm depending on the status of the speed selector switch S2 4 6 Digital signal processing 4 6 1 Digital inputs Digital IO 0 motor on off high when contactor K1 on Digital IO 1 Digital IO 1 broke down see 7 5 Digital IO 2 motor selector clock anti clockwise low when S4 on 0 else high Digital IO 3 heating filament on off high when contactor K2 on Digital IO 4 machine power on off high when machine power on Digital IO 5 error frequency converter low when error occurs Digital IO 6 error security coupling low when error occurs 4 6 2 Digital outputs Digital IO 7 motor on off high sets K11 on K11 sets K1 on Damian Frey High Temperature Tribometer Simon W est 30 69 n iU Foch kachala El volves techevelt EMPAQ Hogheshiule t r Technik Materiais Scienco amp Technology 5 Program 5 1 Documentation In this document only a rough overview over the software architecture is written Most of the documentation is directly written in the LabVIEW program code In the code lots of small notes briefly describe what is done Each VI is documented with a short description of what is done Al
11. 4 4 IO declaration 4 4 1 DAQ Card IO number IO name PIN PIN GND Analog Input 0 Fn 68 34 Analog Input 1 M 33 66 Analog Input 2 Fn2 Room temperature force module 65 31 Analog Input 3 Ft2 Room temperature force module 30 63 Analog Input 4 Motor fast slow 28 61 Analog Input 5 Current R 60 26 Analog Input 6 Current S 25 58 Analog Input 7 Current T 57 23 2 a Digital IO 0 Motor on off 52 8 5V E Digital IO 1 Motor slow fast broken 17 14 5V Digital IO 2 Motor direction clockwise anti clockwise 49 8 SV Digital IO 3 Water on off 47 14 5V Digital IO 4 Tribometer has power 19 Digital IO 5 Error frequency converter 51 14 5V Digital IO 6 Error coupling 16 14 5V Counter Input 0 37 4 Counter Input 1 Incremental encoder 42 4 Analog Output 0 Heating 22 55 H Analog Output 1 Motor frequency converter 21 55 amp Digital IO 7 Motor on off Darlington driver gt K11 48 9 GND 8 SV 4 4 2 Temperature card Temperature Channel 02 Sample temperature Temperature Channel 03 Oven temperature Temperature Channel 04 Strain gauges temperature Temperature Channel 05 M Sensor temperature Temperature Channel 06 Temperature Channel 07 Temperature Channel 08 Temperature Channel 09 Temperature Channel 10 Temperature Channel 11 Temperature Channel 12 Temperature Channel 13
12. 2 Damian Frey High Temperature Tribometer Simon Wiiest 23 69 n LU Fochhoehestinle Hordzesectechsseiz HV Hochschule AR Mar is Science amp Technology During the first experiments we realized that the normal force increases with the rotating arbor Due to this fact the modulation of the carrier frequency amplifiers channel 3 exceeded the critical level We had to change the basic parameter of the measuring range from 0 2 to 0 5 mV V Therefore we had to ascertain another formula for this calibration shown in Ill 31 Carrier frequency amplifiers channel 3 settings for calibration e Set the basic parameter of the measuring range to 0 5 mV V characteristic curve Fn high temperature with basic parameter 0 5 250 00 200 00 _ 150 00 Z c LL 100 00 50 00 0 00 E T T T T T 0 000 0 500 1 000 1 500 2 000 2 500 3 000 UIV measured normal force calculated normal force Fn 86 79355 U 1 71267 Ill 31 Characteristic curve high temperature normal force with basic parameter 0 5 Another problem is that the geometries of the lever force change and the measured voltage decreases with the increasing oven temperature Therefore we measured the normal force error in relation to the oven temperature We loaded the lever with a constant load and heated up the oven We recorded the measured normal force and the oven temperature Damian Frey High Temperature Trib
13. 2 3 i BEB AZENREEBRANBENND ATA j i i i Ill 26 Terminal block frequency converter Damian Frey High Temperature Tribometer Simon W est 17 69 nu Materials Science amp Technology 4 3 6 Terminal block AAA Lui Iul I I Als Ald Al GND AI 10 AI3 AI GND AI 4 AI GND Al 13 AI 6 Al GND Al 15 AO 0 AO 1 AO EXT REF Po4 D GND P0 1 PO 6 D GND 5 V DGND DGND PFI 0 Al START TRIG PFI 1 Al REF TRIG D GND 5 V D GND PFI 5 AO SAMP CLK PFI 6 40 START TRIG DGND PFI S CTR O GATE CTA 0 OUT FREQ OUT Ill 27 Terminal block X3 X4 X5 X6 and Pinout NI terminal block X7 P0 7 P0 3 Al HOLD COMP EXT STROBE D GND PFI 2 Al CONV CLK PFI 3 CTR 1 SRC PFI 4 CTR 1 GATE CTR 1 OUT D GND PFI 7 Al SAMP CLK PFI 8 CTR 0 SRC DGND DGND Damian Frey Simon W est 18 69 High Temperature Tribometer O a e eta 4 3 7 Part list Label Name ii bt Type OO A A A JETI current meter hall sensors LEM HX 15 P multiplexer MPC509A ES operating hours meter AEG LZ 4 Darlington driver ULN2803A 88509 EN end switch security coupling Mayr 055 001 5 EQ incremental encoder K bler 05 2400 1122 0500 BE motor circuit switch CT 1 10 EA circuit breaker Weber LS LG 6A circuit breaker Weber LS LG 15A El lamp fluorescent lamp 30cm ESI signal lamp Luxram 220 260V 7 10W 573 s
14. 300 250 oU Wes 200 2 150 n E 100 50 Y 0 T T T T T 21 50 57 21 53 50 21 56 43 21 59 35 22 02 28 22 05 21 time sample temperature oven temperature Ill 55 Temperature diagram room temperature gt As shown in Ill 54 the friction coefficients measured with the room temperature and the high temperature sensors are not equal With a better calibration of the sensors or further signal processing the results could possibly be improved Damian Frey Simon W est 55 69 High Temperature Tribometer n LE isse esee EMPAQ Hoahectule f r Tashnik Materiais Science amp Technology 6 3 Different sampling and saving rates If the sampling or the saving rate is changed the diagrams of the friction coefficient change as well The following diagrams show the differences Programmed temperature room temperature programmed distance 1 000 m saving rate 500ms 0 4 0 35 0 3 0 25 HL 0 2 0 15 0 1 0 05 0 200 400 600 800 1000 distance m sampling 100ms saving 500ms sampling 10ms saving 500ms sampling 2ms saving 500ms Ill 56 Diagram with different sampling rates at 500ms saving rate saving rate 100ms 0 5 0 45 0 4 0 35 0 3 0 25 0 2 0 15 0 1 0 05 0 200 400 600 800 1000 distance m sampling 100ms saving 100ms sampling 10ms saving 100ms sampling 2ms saving 100ms
15. AAA rtr rie arde 17 4 3 5 Terminal block frequency converter essere nennen nennen 17 43 6 Terminal block nie eee Ee d Ree eee ete bue 18 43 7 Part sU osten ee casted pet tt E id 19 4 4 TO declaration oic meet idee eese ee a 20 441 JXAQ Catrd endi temo ar rent eder eee eie ertet ete erede dy 20 442 Temperature Card tete deerit em ete te oeste ee uaa td prd Dr decus 20 4 5 Analog signal Processing Helene ns 21 4 5 1 Current measuremenht detener teeth nd e a pee ee ere ester en 21 4 5 2 Rotation speed measurement sese rennen nne etes teretes 22 4 5 3 Calibration of the force sensors nennen nennen nnne nnne 23 4 5 4 High temperature measurement sese nennen nenne enne nennen 23 4 5 5 Room temperature measurement coooonconnncnonnnnnncnnnonnncnnnnnnnnnonncnnnn non rennen nne nnne nennt nenne 27 Damian Frey High Temperature Tribometer Simon W est 1 69 Fa dU Hanse EMPAQ Mi Hoahestule tr Toimik Materiais Scienco amp Technology 4 5 6 Temperature measutemlent ee eite lernen 30 do Analog OUtplt Waza 30 4 6 Digital signal Process 30 4 6 1 Digital inputs iiie ene cta nte RB 30 46 2 Digital Outputs vacia iaa 30 SD A NN 31 5 1 Documentation RR Her E a kin 31 5 2 Important i dd eiie Ee ia 31 5 3 General architecture Een 31 23 3 1 Creating PLOT 1 MASSA DAS SAAN 31 3 3 2 o A nen ee eere enero nens 35 5 3 3 Tools to adjust and calibrate the softw
16. Integral time temperature controller Offset speed controller Multiplier speed controller Lower limit speed controller Upper limit speed controller Integral time speed controller Temperature tolerance Speed tolerance Temperature channels Temperature update port Machine protocol port Description The speed controller uses a PID controller and a linear function which sets the output in dependence of the speed to achieve This value determines how the linear function and the PID controller share the output The PID controller may influence the output between 0 and 100 This value sets the influence of the PID controller in percent This value is added to the output of the temperature controller creating a permanent offset This value is multiplied with the output of the temperature controller creating a permanent gain The output of the temperature controller cannot be smaller than this value The output of the temperature controller cannot be greater than this value Defines how many seconds the temperature controller should look back to compute the integral term This value is added to the output of the speed controller creating a permanent offset This value is multiplied with the output of the speed controller creating a permanent gain The output of the speed controller cannot be smaller than this value The output of the speed controller cannot be greater than this value Defines
17. also be called manually Name File name Path Function Tribometer start vi Jstart start vi Data management system and main application New editProgram vi createProgram Creates new programs program _editProgram vi Run runExperiment vi control Executing an experiment experiment _runExperiment vi Change changeGlobal vi general global User interface to change the settings _changeGlobal vi software settings Test settings testGlobal vi general global Interface to test the software _testGlobal vi settings on the running tribometer M RPM M RPM vi start tools M RPM vi Speed up the motor and documents the idle torque as a function of the rotation speed Fn T Fn T vi Jstart tools Fn T vi Heats up the oven and documents the normal force as a function of the temperature Temperature tempMeasurement tempMeasurement Server applications which measures sever _TCP vi tempMeasurement_TCP vi the temperature and sends the data over TCP to the main application 5 5 Hidden functions Function Key Description All functions CTR H Opens and closes the context help Run experiment F12 Opens a window which shows to control output signal for the motor and the heating element F9 Reset the counter Test settings F12 Opens a window which shows to control output signal for the motor and the heating element F9 Resets the counter Simulation F12 Start stop running the simulation in real time Damian Fr
18. calibration e Set the basic parameter of the measuring range to 0 5 mV V characteristic curve Fn room temperature Fn N 1 000 0 000 1 000 2 000 3 000 4 000 5 000 U V measured normal force calculated normal force Fn 36 80005 U 3 99248 Ill 36 Characteristic curve high temperature normal force with room temperature force module Damian Frey High Temperature Tribometer Simon W est 27 69 n VE Focbh chzehnls Horkeesteclesen EMPAQ Hoghechule t r Technik Materiais Science amp Technology Analog Input 2 room temperature normal force Ill 37 Calibration of the room temperature normal force Carrier frequency amplifiers channel 2 settings for calibration e Set the basic parameter of the measuring range to 2 mV V e Set the output voltage to 0 0 V with the unloaded module R balance e Note that the modulation must not exceed the critical level with maximum load C balance characteristic curve Fn2 140 00 120 00 100 00 80 00 Fn2 N 60 00 40 00 20 00 0 00 0 000 0 500 1 000 1 500 2 000 2 500 3 000 3 500 4 000 4 500 U V measured normal force calculated normal force Fn2 28 32117 U 1 29924 Ill 38 Characteristic curve room temperature normal force Damian Frey High Temperature Tribometer Simon W est 28 69 n VE resbhoctestile Horkeesteclesen EMPAQ Hashzshule t r Technik Mate
19. level This information will be loaded with the program when an experiment is run If necessary the operator can then still make some adjustments The program with all the additional information finally has to be saved The software will create four separate files with the same name but different file extensions It is therefore recommended to use an extra folder for each program New step New step Ill 41 User interface to create a program step Damian Frey High Temperature Tribometer Simon W est 32 69 n Ww Fachhoshachula Moniveseteshveit EMPAQ Hoghechule t r Technik Materiais Science amp Technology 5 3 1 1 Simple program The above described programming interface is very flexible but for most experiments not very comfortable because quite a few steps have to be create for a simple standard program Simple standard programs work through the following steps Heat up to a certain temperature if it is not a room temperature experiment Set a breakpoint Start measuring Speed up the motor to a given speed Wait until a certain time or distance is over Stop the motor Stop measuring Turn off the heating if it is not a room temperature experiment A INES Ua aces Instead of a normal program the user also can create a simple program which contains just the above listed steps The entire program can be created in one single user interface On this graphical interface an approximation of the total time and the total di
20. thread could then use up to much CPU time The rate in milliseconds how often the system calculates the mean value of all samples acquired and saves them to the hard disc 500 ms Increasing this value will create less data points per time and therefore saves disk space Be aware that this appends at the cost of the accuracy since small details are no longer visible The rate in milliseconds how often the system calculates the current target values and sets new signals for the motor and the heating element If the system need more time to sample then defined here an error will be reported If the system needs more time to save the acquired values then defined here an error will be reported The rate in milliseconds how often the system tries to update the speeds If this time is chosen to short the speed may be inaccurate The rate in milliseconds how often the system tries to update the temperature on the remote computer 100 ms 10 ms 600 ms 1 000 ms 2 000 ms Be aware that updating the temperature needs at least one second Updating the cold junction sensor need approximately another second If this value is chosen to small the remote computer cannot send a new temperature update before a timeout occurs The timeout time is twice the temperature update rate The rate in minutes how often the system updates the value of the cold junction sensor on the remote computer The rate in milliseconds how often the sy
21. which frequently sends back the new temperature values over the local area network TCP A thread continuously listens for new temperature updates from the remote computer Damian Frey High Temperature Tribometer Simon W est 36 69 5 3 2 1 4 Data sampling This is the most frequently repeated thread It measures a sample of all forces and bundles them together with the temperature values and the speed to a single data point The data points are then written to a first in first out FIFO queue The data points are further used by the data saving thread 5 3 2 1 5 Data saving With a distinct frequency the enqueued data points are flushed and the data is prepared to write to a file For each force channel temperature channel and the speed the mean value is calculated In addition the mean the maximum and minimum value of the friction coefficient are determined The compressed and processed data is once again bundled with a timestamp to a single data point and written to another queue 5 3 2 1 6 Writing data to file This low priority thread waits for new enqueued data and machine protocol entries and writes them to a csv file 5 3 2 2 Temperature measurement The temperature is measured on a second computer since a single temperature measurement blocks all resources for approximately one second Measuring the cold junction sensor needs another second time The server application of the temperature measuring computer continuously
22. 04 6000 0 096 In x 0 2498 86 79355 x 1 71267 TE 07 x 3 0 0008 x 2 0 100 x 5 3268 36 80005 x 3 99248 28 32117 x 1 29924 44 60995 x 0 01965 x 3 75 Damian Frey Simon W est High Temperature Tribometer 42 69 n LU Fechhoshectinls Horlvzertecheyen r Wa Hoahestiule tr Technik Materiais Scienco amp Technology Simulation mun Variable Wait before program s Wait after program s Default path of programs Default path of experiments dossiers 1112 Tribometer model Resistance of the heating wire Ohm Tribometer model Heat leakage W C Tribometer model Heat inertia J C Tribometer model Rotation moment of inertia kgm2 Tribometer model Max acceleration Hz s Frequency Converter model Max heating current A Dimmer model Max signal V Dimmer model Email server Description The system waits for this value in seconds before starting the program You may use this time for example if you want the machine to come to a complete rest before starting the experiment The system waits for this value in seconds after the program is completed You may use this time to wait for any additional remote machine reports or errors This is the default directory where all the programs are saved in the program management system This is the default directory where all the experiment dossiers are saved in the progr
23. DIPLOMA PAPER DOCUMENTATION Optimization of a High Temperature Tribometer Diploma Project by Damian Frey and Simon W est Project numbers Industrial Customer Project members Major Project Supervisor Methodic Coach Project website Date 4008 5 4028 8 EMPA Thun Mousab Hadad Dr Johann Michler Damian Frey Simon W est Systems Engineering 6 semester Prof J rg Sekler Prof Martin Kl ti tech wueest name tribometer Windisch August 15 2008 nc c Materials Science amp Technology Version Table Version Changes Date August 04 2008 August 14 2008 Damian Frey High Temperature Tribometer Simon W est 1 3 n LO pisi tte EMPAQ Hoahestule tr Technik Abstract At EMPA Thun several tribometers are used to analyse material abrasion In the context of a two semesters project at the University of Applied Science of Northwestern Switzerland an existing tribometer for so called block on ring experiments was modernized concerning data acquisition and device control and upgraded with additional functionality high temperature experiments In the first part fifth study term the tribometer was completely disassembled for the analysis of the system functions and the evaluation of different possibilities for improvement The electrical schema of the equipment was noted since this was missing in the existing documents The main task in the first part of the project c
24. ahectule f r Tastanik Materiais Science amp Technology 0 35 0 3 44 0 25 0 2 HO 0 15 0 1 0 05 0 1000 2000 u steel on steel 3000 4000 5000 distance m u Steel on steel Ill 51 Friction coefficient as a function of the distance 350 300 250 200 T C 150 H 100 50 0 12 02 18 12 09 30 12 16 42 time temperature diagram einer hs PAR ARA PPP TERRITI RR a 12 23 54 sample temperature oven temperature 12 31 06 Ill 52 Temperature diagram Damian Frey Simon W est 53 69 High Temperature Tribometer le t r Technik n QU S wla Hordssectechssetz 6 2 Room temperature experiment We made an example room temperature experiment for the documentation Every report as the following contains links to the program details the settings the machine protocol the raw data and more diagrams Experiment report 00000000E Example experiment room temperature Created on Donnerstag 14 August 2008 22 06 11 General Customer EMPA Operator Damian Frey Dossier Nr 000000001 Experiment Nr 00000000E Name Example experiment room temperature Description An example experiment for the documentation Sample Material Density Diameter Initial weight Post experimential weight Weight loss Volume loss Wear rate Cleaning Manufacturer Note Lubri
25. am management system This value is the relation from the length of the large lever with the weight load to the length of the small lever with the block sample This value is used to calculate the simulated normal force form the simulated load The resistance of the heating wire in Ohm This is the characteristic value for how much heat the tribometer looses If the tribometer model is assumed to be a thin walled cylinder the heat leakage can be defined as follows Heat leakage W K heat conductivity W m K pi inner diameter m cylinder length m cylinder thickness m This is the characteristic value for how much heat the tribometer needs to increase the temperature If the tribometer model is assumed to be a homogeneous volume the heat inertia can be defined as follows Heat Inertia J K mass kg specific heat capacity J kg K The rotation moment of inertia of the motor and the tribometer The maximum acceleration of the motor in rounds s which the frequency converter allows The maximum heating current in Ampere the dimmer allows The maximum signal in V which the dimmer accepts The SMTP email server which is used by the software to send emails to the operator Default value 5s 5s 1 8251 10 Ohm 2 5 W C 2400 J C 1 2444E 3 5 Hz s 16 A 10 V Damian Frey Simon W est High Temperature Tribometer 43 69 njw ce Materiais Scienco amp Technology
26. anono nono nono eem nennen 61 A IECIT 62 8 1 Replacement heating element ooonnccnnccnnccnoccconcconnconaconanonnncnnncnnncnnncnn ccoo nrnnnranncanc cnn ncrn ancianos 62 Damian Frey High Temperature Tribometer Simon Wiiest 2 69 a dU Zander EMPAQ ME Hoahestule thr Technik Materia Sclence amp Technology 8 1 1 Replacement THERMOCOAX filament sees 62 8 1 2 Ceramic haini ricas 62 8 1 3 Other possibilities ier ido EEG 62 8 2 Formula for idle torque correction sees nennen 63 8 3 Formula for normal force error in function of the oven temperature esses 63 8 4 Fixation of the oven temperature sensor essere nre enn rennen nenne 63 8 5 Mechanical damping of the motor support nennen 63 8 6 Alignment of the rotating arbor ii 63 8 7 Vest security coupling 3 dei d He Han 63 8 8 Cover for the rotating elements security esses ener 64 8 9 GIN CIIM EC nenne 64 8 10 Test the reliability of the tribometer eese 65 8 10 1 Counter proble MS tocaran ip R 65 8 11 TANIA ennemi enit nnet nnne nnr etre ten ette tenentes 65 8 12 Temperature monitoring of the room temperature force module sss 65 9 JXddendutn eo daa 66 9 1 GIOSSAEY oia lala 66 9 2 List of illustrations 2 e nde ae ek RER 67 Damian Frey High Temperature Tribometer Simon W est 3 69
27. are oooonncnnnnnnninncnnncncooncnnncnrncnnnc nono nono can ccnnnnnn canos 38 5 3 4 Calibrating the ti ccoo ncnn cnn ncon nennen enne nnne 46 5 3 5 Data management system iieteeneneneneneneneneooneeaneeeneeneneneneneneeeneeeteeeneeeneeene ena 47 5 4 Main Visit kin eek 48 5 5 Hidden functions 32 2 eret idas 48 5 6 Problems 49 5 6 1 Temperature measurement eene nennen nennen nn nn nn rennen ener eene eterne 49 3 0 2 Brocken Digital JO T i ee o e seh ren ie 49 5 7 jb ES 50 5 8 Optimization aaa 51 6 Test xperimment eade ete eere toni nie nee rH e e eb eret SU ee es 52 6 1 High temperature Expedia 52 6 2 Room temperature ai nennen nnne rennen eren ene neret nnne 54 6 3 Different sampling and saving rates eese enne nennen rennen 56 6 4 Regulation of oven or sample temperature miereeereoereeeneeenneonneoeneoeneenneeenee et 58 7 Problems and their solutions ereereeeneeneneneneonneooneeeneenneeeneneneneneeeneeeneeeneeeneeene ere 59 7 1 SHIA 59 72 Heating element and Gimme vecindades netten 59 B see ONO 59 1 22 Heating element lamen iii di dis 59 7 3 Temperature measurement centre treten te tne nn 60 7 4 Installing the room temperature force module eene 60 7 5 Breakdown of LabVIEW Digital IO 1 ooonnonnccnnccnoconoconocononnnonnconccon
28. bometers behavior This makes the software very easy adjustable without having to change the program code Nevertheless the operator still has to be careful if he makes any adjustments A poorly configured software may stop the tribometer from working properly E Change settings Signal to unit conversion Wait Pathes Simulation Email Hardware Max temp torque Rates Controller parameter Controller adjust Tolerance Temperature channels ports Temperature Overheat protection Torque Max oven Upper temperature C threshold BE Max torque Nm Joo Jo Max temperature of Lower the strain gauges C threshold 95 J 100 Ji 480 Max temperature of the torque sensor C jo View default setting Save amp test settings Ill 46 User interface to adjust the settings In the table below the settings are listed Variable Description Default value Mazimum oven The maximum allowed oven temperature If this value is 800 C 3 temperature exceeded the experiment will be cancelled and the E tribometer will be shut down kas Maximum This is the maximum allowed temperature of the strain 100 C temperature of gauges If this value is exceeded the experiment will be g the strain gauges cancelled and the tribometer will be shut down to protect the strain gauges 5 Maximum This is the maximum allowed temperature of the torque 40 C temperature of sensor If this value is exceeded the
29. cant none Lubricant mass 0 000000 g Lubricant application Atmosphere air Load 40 000000 N Fn 69 837543 N Distance 5034 261736 m Note none Program settings Block Steel 7 800000 g cm 3 150 000000 g 148 000000 g 2 000000 g 0 256410 cm 3 7 293074E 4 mm 3 N m none EMPA none Program name Standard room temp experiment Program description A standart room temperature experiment without the force module Speed 6 m s Distance 5 km Program details Settings Machine protocol Ring Steel 7 800000 g cm 3 40 000000 mm 200 000000 g 197 000000 g 3 000000 g 0 384615 cm 3 1 093961E 3 mm 3 N m none EMPA none Date Time Start time 14 08 2008 21 50 53 End time 14 08 2008 22 05 36 Data Raw data csv Graphs HTML Ill 53 Report room temperature experiment Damian Frey Simon W est High Temperature Tribometer 54 69 n 1 Hone en ae eo iid NV Glad AH 0 8 ifi 07 M 0 6 4 I Td 7 0 5 PM MNT FIN NIE BIN NN my i SAA P PA A KUTI a FI f LAN PUE A KAA dd i WA dl i i Mii hin dll m Y lud N um lil JA PAAR AN ga DN 0 3 fT 0 2 0 1 0 T T T T T 0 1000 2000 3000 4000 5000 distance m y steel on steel high temp sensors y steel on steel room temp sensors Ill 54 Friction coefficient as a function of the distance room temperature temperature diagram
30. controller 0 5 which is defined as follows y t Kp e t Ki int e t dt Kd diff e t dt This value defines the derivative term Kd of the PID controller The speed controller uses a PID controller and a linear 0 function which sets the output in dependence of the speed to achieve The PID controller is defined as follows y t Kp e t Ki int e t dt Kd diff e t dt This value defines the proportional term Kp of the PID controller The speed controller uses a PID controller and a linear 0 5 function which sets the output in dependence of the speed to achieve The PID controller is defined as follows y t Kp e t Ki int e t dt Kd diff e t dt This value defines the integral term Ki of the PID controller The speed controller uses a PID controller and a linear 0 function which sets the output in dependence of the speed to achieve The PID controller is defined as follows y t Kp e t Ki int e t dt Kd diff e t dt This value defines the proportional term Kp of the PID controller Damian Frey Simon Wiiest High Temperature Tribometer 40 69 nc n hhostechals Horbresteoleveit tule dure shirk Materiais Scienco amp Technology Controller adjust Tolerance Temperature channels Variable Quantifier Offset temperature controller Multiplier temperature controller Lower limit temperature controller Upper limit temperature controller
31. cquire The key part of the software is the tribometer control and the data acquisition This is realized with a few parallel threads which all handle a specific task 5 3 2 1 1 Compute the target values and control the tribometer This thread makes sure the tribometer behaves just like the operator programmed the experiment First it loads the current step and then computes the target temperature and the target speed Then it sets the output control signals for the heating and the frequency converter motor The output signals are computed with PID controllers depending on the target values with actual speed and temperature Finally this thread checks if the conditions are met to load the next step 5 3 2 1 2 Measure the speed and the elapsed distance The speed and the distance are measured with an incremental encoder and a counter port on the data acquisition card form National Instruments The incremental encoder returns 500 impulses for each complete turn of the motor The counter continuously counts the impulses The software frequently reads the number of counted impulses With the count difference and the time difference the speed is calculated The total number of impulses can be converted into the total elapsed distance the ring samples surface scratched on the block sample To make this calculation the ring samples diameter has to be known 5 3 2 1 3 Listen for new temperature values The temperature is measured on a second remote computer
32. dditional support shown in Ill 12 had to be built to the machine to hold the motor and the torque sensor Damian Frey High Temperature Tribometer Simon W est 10 69 Ill 12 Schema of the new system with complete support The force in the force lever is measured with four strain gauges They are glued in the thin part on the axis indicated in light green in Ill 14 The strain gauges can stand temperature up to 200 C Since the strain gauges are already in the cooled part of the back door there should not be any overheating problems To avoid possible damage due to overheating a thermocouple measures the strain gauges temperature If necessary this allows taking immediate actions during an experiment The strain gauges are evaluated with a carrier frequency measurement amplifier EMPA already used such an amplifier built by the company HBM We reused this amplifier but we have to keep in mind that the amplifier is quit old and HBM does not provide any support or guaranty The temperature in the oven is measured with two thermocouples One thermocouple is mounted near the probe to measure the probe temperature The other measures the temperature of the ovens atmosphere Ill 13 The arbor the torque sensor and the motor aligned in one line All the housing is removed in this image so it can be seen how the arbor and the torque sensor is aligned in one line to simplify the system as much as possible Damian Frey High Tem
33. e of that the LabVIEW Digital IO 1 broke down because of the 15 VDC which were connected to its clamp it stands a maximum of 5 5 VDC Fortunately no other damage was done to any sensors and the LabVIEW card The solution Analog Input 4 gt motor speed selector slow fast high when S2 on fast The Analog Input 4 serves now as a Digital Input and replaces the Digital IO 1 Because the readout of an analog input takes more time the detection is slower than with a digital input Damian Frey High Temperature Tribometer Simon Wiiest 61 69 Materials Science amp Technology njw cs 8 Future tasks 8 1 Replacement heating element As we could not repair or replace the heating element in time we agreed to suggest some possible solutions 8 1 1 Replacement THERMOCOAX filament The installed filament is a product of THERMOCOAX www thermocoax com A replacement costs about CHF 1200 We got an offer from the Swiss THERMOCOAX sales representative Thermocontrol GmbH www thermocontrol ch This is an offer for a similar filament which stands constant temperatures up to 600 C and supply powers up to 1 500 W The thicker filament up to 1 000 C can not be installed on the same pillar Therefore a complete heating element with the high temperature filament must be ordered The catalogue with the standard products of THERMOCOAX can be downloaded on the company s website 8 1 2 Ceramic heating element The company PROBAG W rmetechn
34. easuring remote computer often reports an error on its GUI because it could not send a temperature update and the error to it This happens because the client main program starts to listen for temperature updates and errors too late or because it stops to listen too early This small bug has no impact on the functionality of the system e The server application on the temperature measuring computer does not allow starting and stopping measuring the temperature on the local GUI It can only be started with the main program over the local area network e If in the data management system a new unit dossier experiment or program is created the system reloads its list so the lists are up to date However it does not go automatically to the newly created position So the user first needs to scroll to this new position A better search function could also be helpful e The data management system scans through all dossier and the experiment to create a complete list This is very time inefficient Therefore loading a new dossier with a lot of experiments takes a lot of time Damian Frey High Temperature Tribometer Simon W est 51 69 lo t r Technik Materiais Science amp Technology nje ke EMPAQ 6 Test experiment 6 1 High temperature experiment We made an example high temperature experiment for the documentation Every report as the following contains links to the program details the settings the machine protocol the ra
35. en in the interface Run experiment the hidden function F12 is used which shows a window with control signal output the program can not proceed when the experiment is done The software basically waits idle for ever until the user closes this window How can the user avoid it To avoid this error the user need to click aside the field he last edited prior saving the program Tf this error should occur there is no other way then to renew the report To do so load the experiment in the data management system click on Recreate report and check if the graphs are now correct Tf this error should occur close all windows of the tribometer software and restart the application Close this window when it is not used especially when you leave the tribometer for a longer time Damian Frey Simon Wiiest High Temperature Tribometer 50 69 njo ki EMPAQ hule f r Technik 5 8 Optimization Below a few optimization possibilities are listed which could not be implemented until the end of the diploma thesis e The counter which counts the impulses from the incremental encoder is limited after a certain number of counts the counter will overflow To prevent an overflow the counter is reset before the limit is reached Resetting the counter needs some time so some impulses might get lost This could be better solved if a function is created which simply detects the overflow e The server application on the temperature m
36. equency amplifier and wrote them with the corresponding load forces in a table please note that the channels of the carrier frequency amplifier must be calibrated as well the settings are noted near the characteristic curves We increased the load stepwise 1 kg per step The data points were converted to an approximate linear function with the MATLAB function polyfit 4 5 4 High temperature measurement 4 5 4 1 Normal force Analog Input 0 high temperature normal force To calibrate the normal force strain gauges measuring bridge a precise balance is needed to measure the load To retain the exact geometries of the fully installed tribometer it is important to install the balance exactly where the ring sample is normally installed Carrier frequency amplifiers channel 3 settings for calibration e Set the basic parameter of the measuring range to 0 2 mV V e Set the output voltage to 0 0 V with the unloaded lever R balance e Note that the modulation must not exceed the critical level with maximum load C balance characteristic curve Fn high temperature with basic parameter 0 2 250 00 200 00 150 00 Fn N 100 00 50 00 0 00 T T T T T T 0 000 1 000 2 000 3 000 4 000 5 000 6 000 7 000 U V measured normal force calculated normal force Fn 35 98439 U 3 42451 Ill 30 Characteristic curve high temperature normal force with basic parameter 0
37. es and the wires connecting them got brittle and partly broke We decided to simply replace them The replacement was done by the company HBM they also mounted a temperature sensor near the strain gauges to observe the temperature of the strain gauges they work up to 200 C Advantages Disadvantages e Space saving measurement e Calibration is necessary e Stands temperatures up to 200 C ead E I ee Tels Ill 8 Strain gauges on the lever Ill 9 Carrier E amplifier KWS 503C Damian Frey High Temperature Tribometer Simon W est 8 69 4 The new Tribometer The datasheets and user manuals are on the project CD They are in the folder datasheets 4 1 Mechanics From the three solutions described in the first term project documentation we chose in agreement with the customer to realize the adequate solution It is therefore documented here more detailed and concrete 4 1 1 General description The basic idea to measure the torque precisely is to mount the torque sensor as close to the probe as possible Since the torque sensor cannot stand the heat we had to mount the senor outside the oven right after the oil feed system In Ill 11 the torque sensor is shown in light green The arbor used to be driven over a V belt form the motor which was mounted in the support This is not possible anymore since the torque sensor uses up to much space Therefore we had to find a new way how to bring the rotation f
38. evant for the switching condition For example when the temperature should rise to 500 C the program will switch to the next step as soon as the temperature reaches 500 C plus minus the tolerance Damian Frey High Temperature Tribometer Simon Wiiest 31 69 EMPAQ Materials Science amp Technology For each step three sets of parameters can be defined The switching conditions can be a combination of one two or all three sets of parameters For example e Heat up to 500 C and speed up to 7 m s Switch to the next step if both AND target values are achieved e Heat up 500 C and wait for 10 minutes Switch to the next step if the temperature reaches 500 C OR the time is up e Wait for 5 seconds and speed up to 3 m s Switch to the next step when the time is up no matter if the target speed was achieved or not e Heat up to 500 C speed up to 7 m s and wait until 1 km distance is over Switch to the next step if all three AND target values are achieved etc To each step the user can provide a step name If the user uses precise expressing names the program can be easy read To the actual program the user can provide a series of addition information To each program a program name and a description can be entered Usually with one program the same or similar samples are testes To save the user typing work some information about the sample such as material density diameter etc can already be provided at this
39. experiment will be 2 the torque sensor cancelled and the tribometer will be shut down to E protect the torque sensor S Upper threshold This function is used to protect the tribometer from 650 C E overheat overheating If the oven temperature exceeds this gt protection threshold the heating will be turned off The tribometer will not be shut down and the experiment continues Damian Frey High Temperature Tribometer Simon Wiiest 38 69 nic p hhostechals Horbresteoleveit al tule dure shnik Materiais Scienco amp Technology Variable Lower threshold overheat protection Maximum torque Sampling rate Saving rate Working rate Max sampling rate Max saving rate Speed update rate Temperature update rate Cold junction sensor update rate min Chart update rate Current update rate Default value 630 C Description Tf the heating was turned off because the oven temperature got to high the tribometer will gradually cool down When the temperature falls under this value the heating will be turned on again The maximum allowed torque If this value is exceeded the experiment will be cancelled and the tribometer will be shut down The rate in milliseconds how often the system tries to sample the process parameters In general the tribometer will return better results when this value is kept small 6 Nm 2 ms Attention This value should not be chosen to small since the sampling
40. ey High Temperature Tribometer Simon W est 48 69 njw mapa EMPAQ hule tht Teehnik 5 6 Problems 5 6 1 Temperature measurement While running the first test it turned out that the temperature measurement uses at least one second to update the temperature channels and another seconds to update the cold junction sensor This would not be too much a problem if a temperature update would not block the entire resources while measuring In other words no other data channels can be read for one to two seconds while the temperature is measured This is simply not useful To solve this problem the temperature measurement was outsourced to a second computer which does nothing but measuring the temperature and provide the acquired data to the main program On the temperature measuring computer runs basically a server application The sever sends continuously the temperature values to the client main program of the local area network using TCP Transmission Control Protocol The client can send command signals and configuration data to the server This way the client can send signals to the server to start or stop measuring and can configure the temperature channels This solution of this problem was realized in an acceptable time is cheap and fairly robust This brings the disadvantage that two computers need to run parallel in order to use the tribometer The computers also need to be connected over the local area network 5 6 2 Brocken Dig
41. how many seconds the speed controller should look back to compute the integral term The temperature controller tries to regulate the temperature as close to the target value as possible However it will never achieve the exact target value There will be always a small error This value determines the tolerances in which the temperature has to be so the program can switch to the next step The speed controller tries to regulate the speed as close to the target value as possible However it will never achieve the exact target value There will be always a small error This value determines the tolerances in which the speed has to be so the program can switch to the next step Configure each temperature channel Number of the temperature channel 02 15 Channel number smaller than ten need to start with a zero Type of the thermocouple The port on the local computer on which the system listens for new temperature values The port on the local computer on which the system listens for new machine protocol entries created by the remote computer Default value 5 OV 10 V 30 s OV 10 V 30s 0 1 m s CH02 K CH03 K CH04 K CH05 K 6001 6002 Damian Frey Simon Wiiest High Temperature Tribometer 41 69 n LU Fochhoehestinle Hordzsectechsseiz NA Hasheshula t r Technik Materiais Scienco amp Technology e e Nn E Q gt e 9 m e S en emm un
42. ignal lamp Luxram 220 260V 7 10W 573 Bj electric contactor Sprecher amp Schuh CA1 16 electric contactor Sprecher amp Schuh CA1 16 relay finder LR26716 300V 12A 95 85 1 ESPE ay finder LR26716 300V 12A 95 85 1 E Kii motor Bauknecht RF 1 1 4 72 ventilator Amphenol Tuchel electronics XRO1 pump Unitec SK5 56 B4 ventilator motor cooling Pabst 4412F el resistor filament 10 Ohm SEES turn switch CMC Tp10h Bil selector switch Kraus amp Naimer CA10 7AR198 600E turn switch Kraus amp Naimer CG8 A203 Ea selector switch Kraus amp Naimer C10 A441 light switch for lamp Hl FEET water watcher switch TechnoKontrol transformator O D r ZF 612141 380 150V dimmer varintens LE16 MED DC power supply PULS ML30 106 frequency converter Hitachi L200 EHI voltage regulator LM7805CV EENI terminal block S amp S VR2 2 5 VR1 6 terminal block S amp S VR1 6 ES D Sub jack 15 pole D Sub jack 15 pole ESI D Sub jack 15 pole D Sub jack 15 pole EF Ni terminal block CB 68LP terminal current measurement X8a with multiplexer X8b without multiplexer jack dynamic torque sensor T22 transducer connection cable no 3 3301 0158 D Sub jack carrier frequency amp CH3 25 pole DATEN terminal frequency converter Hitachi L200 D Sub jack carrier frequency amp CH2 25 pole X13 D Sub jack carrier frequency amp CH1 25 pole Damian Frey High Temperature Tribometer Simon W est 19 69 n LU Fachhochashula Morlveseteslevelt Me Hegheshufe f r Till Materiais Scienco amp Technology
43. ik www probag ch sales several heating elements They have ceramic heating elements which stand constant temperatures up to a maximum of 650 700 C We have no offer but at the phone Mr Reto Probst could make a rough calculation A ceramic heating element would cost about CHF 1 000 but requires power supply with 230 VAC to reach its full power 8 1 3 Other possibilities We tried to find some more solutions for a high temperature heating element but it turned out to be difficult With a heating fanner temperatures up to 1 000 C can be reached but due to air intermixture the fanner could heat up the hole oven an not only locally at the samples Other companies which sell heating elements are L kon Paul L scher Werke AG CH 2575 T uffelen Leister Schweiz CH 3084 Wabern Walser AG CH 9044 Wald Fridrich Freek GmbH D 58708 Menden Damian Frey High Temperature Tribometer Simon W est 62 69 nc Materials Science amp Technology 8 2 Formula for idle torque correction For a more accurate formula to compensate the idle torque some more measurements are necessary A program to record the idle torque can be found in the tool tab of the LabVIEW start program start vi After recording a formula can be calculated either with Microsoft Excel or MATLAB The formula can be added in the settings tool tab of start vi 8 3 Formula for normal force error in function of the oven temperature For a more accurate formula to c
44. ital IO 1 To replace the broken Digital IO 1 we used the Analog Input 4 A special function replaces the normal digital port read function The normal function is still implemented but currently disabled With one click in startupMachine vi this function can be active again Our new function reads all the other working ports and the analog input 4 It then returns the same result as if the normal port read function was used Damian Frey High Temperature Tribometer Simon Wiiest 49 69 Fochhochestinle Hordzesectechsseiz Haghechule t r Terhnik nc Materiais Science amp Technology 5 7 Bugs The software contains some known bugs which could not be solved before the end of this diploma project What is the bug In the user interface where the operator can program the experiments not all entered data may be saved The reason is LabVIEW applies the entered data to a field after the user clicks outside the field or presses the return button If the user selects save while the cursor is still in a control field the information in this filed might not be saved Sometimes the wrong graphics in the report are converted to a picture and inserted into the report This happens not very often and not on a regular basis When the following functions are called form the data management interface start vi they sometimes close without starting to execute their duty Run experiment Test settings M RPM Fn T Wh
45. know why this happens and if it is a problem of the software or the LabVIEW card 8 11 Program optimization Since we could not afford to program the LabVIEW application perfectly we made some suggestions for further improvements For more information see 5 8 8 12 Temperature monitoring of the room temperature force module As we tested the room temperature force module we realized that the entire module heats up with the frictional heat To make sure that the heat causes no damage to the strain gauges on the module its temperature should be watched Further the measured force could be depending on the temperature of the strain gauges perhaps this should be calculated as well Damian Frey High Temperature Tribometer Simon W est 65 69 n LU Fachhoshachule Monivesetesheveit EMPAQ Haghechule t r Technik Materiais Scienco amp Technology 9 Addendum 9 1 Glossary Description Tribometer A tribometer is an instrument measuring friction and abrasion on a surface There are various methods to determine the friction coefficient Damian Frey High Temperature Tribometer Simon W est 66 69 Materiais Scienco amp Technology n 1 U Fochhoehestinle Hordzsectechsseiz EMPAQ MA Hochschule t r Technik 9 2 List of illustrations Ul 1 Complete tribometer 5t tr rrt ri an aac EE EES 4 Ill 2 Tribometer with the top cover removed emeeeteeeeneneneneneonneonneennnenneeaneenenene
46. l the visible controls and indicators on the GUls have a context help entry This description is designed to interactively inform the user 5 2 Important The tribometer software runs on MS Windows Windows is actually not designed for real time application Opening programs scrolling or switching tabs may use up to much resources and the tribometer application cannot keep up with some tasks in time So try not to use the computer for other tasks while running an experiment We even recommend you not to switch between windows or scroll in a window 5 3 General architecture The software can be divided into four major parts e User interfaces to create programs e Functions to run experiments e Tools to adjust and calibrate the software e Data management system to manage the programs and the experiments in dossiers 5 3 1 Creating a program To run an experiment the user first needs to create a program A program consists of several steps The program executing software works consecutively through these steps In a step the following can be determined e Temperature rise and fall e Speed rise and fall e Wait until a certain time is over e Wait until the ring samples surface scratched a certain distance on the block sample e Start and stop measuring e Breakpoint wait until the user clicks on continue e The switching condition which must be achieved so the next step can be loaded Usually the programmed parameters are also rel
47. n additional project We agreed to look for some possible solutions and describe them in our documentation 8 1 We could repair the heating element provisionally We tested it with a limited current of 5A Limit of the control signal for the dimmer LabVIEW Analog Output 0 is set to 3 VDC see 5 3 3 controller adjust We reached temperatures up to 400 C with the repaired heating element 7 3 Temperature measurement The problem of the temperature measuring and the solution are described in 5 6 1 7 4 Installing the room temperature force module As we tried to install the room temperature force module it did not fit in the tribometer because there was a buckle in the oven tube shown in Ill 63 j a Ill 63 Buckle in the oven tube 12 November 2007 We heated up the oven tube locally with the autogenous welding eguipment and forged the oven tube the buckle close to its designated shape with the hammer Afterwards the room temperature force module fitted in the tribometer Damian Frey High Temperature Tribometer Simon W est 60 69 n LU Fochhocheohuls Norbrestechesen EMPAQ AL Hasheshula thr Technik Materia Sclence amp Technology 7 5 Breakdown of LabVIEW Digital IO 1 As we ordered the wiring of the terminal box a solecism happened We changed the places of the D Sub jack X3 with the D Sub jack X5 by accident Unfortunately we did not realize that before we took the tribometer into operation again Becaus
48. neeeneeenee ed 4 111 37 Dimmer varintens LEAG 0 2 es ea trei eene Pre Pedo eie eei 7 Ill 4 Temperature module NI TC 2190 esses nenne nennen nnne nnne nnne eterne 7 Il 5 Frequency converter Hitachi L200 eese ener nennen ease nennen rennen 7 U6 Dynamic torque SENSOTA iuris 8 Ill 7 Ineremental NA e e dalt aiii 8 11 8 Strain gauges on the lever aaa 8 Ill 9 Carrier frequency amplifier KWS 503C sss eene nene een nemen kaaa 8 Ti 10 Schema of the old system iere 2 are LEN EU e id 9 Ill 11 Schema of the new Systainer bebida eb oues 10 Ill 12 Schema of the new system with complete support uurssurssnesnnessnesnnesnnennnnnnnnnnnnennnennennen nenn 11 Ill 13 The arbor the torque sensor and the motor aligned in one line sees 11 Ill 14 Parts measuring physical values eese nennen nennen rennen nenne 12 Ill 15 Back door with the parts running through it een nemen 12 Ill 16 Security coupling EAS compact Type 493 530 O ooocococccocococococnconnnonnononnnnononononncnonononcnnncnnnn ns 12 Ill 17 Characteristic frequencies of the motor eese nennen nne nennt nnns 13 Ill 18 Characteristic frequencies on the dynamic torque sensor seen 13 Ill 19 Characteristic frequencies on the electric control box eene 14 Ill 20 Characteristic frequencies on the oven tube oooooonccn
49. nts the new test device has to be removed Furthermore the temperature and the rotation speed of the motor are not automatically controlled and have to be regulated by hand In addition the oven does not heat up properly anymore Ill 1 Complete tribometer Ill 2 Tribometer with the top cover removed This text is partly similar with the text from the documentation of the first term project M Instrumentierung und Inbetriebnahme des tribologischen Pr fger tes Tribomat Bericht zur Diplomarbeit von Martin Stettler Hochschule f r Technik und Architektur Burgdorf Abteilung Elektrotechnik EMPA Eidgen ssische Materialpr fungs und Forschungsanstalt 25 10 1999 bis 17 01 2000 Damian Frey High Temperature Tribometer Simon W est 4 69 n iU Fachho kachala El volves techevelt EMPAQ Hoahestule tr Technik Materiais Scienco amp Technology 2 2 Goals 2 2 4 Achieved first term project goals Because the overall project goals exceeded the possibilities of a one semester project the goals are distributed in two term projects In the first term project the device had to be analyzed first to answer the following points 1 Which components do still work Which components have to be replaced Which components have to be repaired Which components can be left away or replaced CA euo Y How can the physical values for the experiments temperature friction force normal force rotation be measured correctly 6 Wha
50. oconoconoconocononoconaconccnnnconn nono nono nono nano rennen 14 Ill 21 Interface terminal box ere eek 15 Ill 22 Power CIECUIL 5 cet 2a edet red ea Det adidas 16 Ill 23 Sienal CIECUIT eid ec I el 16 Ill 24 Current measurement multiplexer current measurement 17 Ill 25 Darlington driver eicere ia eae 17 Ill 26 Terminal block frequency CONVerteT oooonccnnccnococonnnonnconncnnncnnncnnn crac n non ncannc ona nennen nennen nennen nennt 17 Ill 27 Terminal block X3 X4 X5 X6 and Pinout NI terminal block X7 18 111 28 Characteristic Curve CUTE idee ert tahke Ee E vana erp eet Con IR ads 21 Damian Frey High Temperature Tribometer Simon W est 67 69 EMPAQ n Ca nini dm Ill 29 Characteristic curve rotation speed uesseessessnessnessnesnnensnnennnennnennnennnennnonnnnnnnnennnennnennennan nenn 22 Ill 30 Characteristic curve high temperature normal force with basic parameter 0 2 23 Ill 31 Characteristic curve high temperature normal force with basic parameter 0 5 24 Ill 32 Fn error in function of the oven temperature oooooonoconoconocononononnnonnnonnnnnnannnnnnn nennen nen eem rennen 25 Ill 33 Corrected Fn in function of the oven temperature ooooconoccnoconocononnnonnnonncnnncnnnnono nono nono nennen 25 Ill 34 Characteristic curve high temperature dynamic torque eene 26 111 35 AAA 26 Ill 36 Characteristic curve high tem
51. ometer Simon W est 24 69 ni Fachhosteschule Mordcesctector a EMPAQ Hoahestule f r Tanh nik Materiais Science amp Technology The measured normal force must be corrected with the formula shown in Ill 32 It is implemented in the LabVIEW program but the formula is only correct between 30 and 410 C due to the measured temperature range maximum temperature with the provisionally repaired heating element see point 7 2 2 Therefore it is advisable to correct the formula by running this experiment again with a wider temperature range 8 3 Fn N error in relation to T C 200 150 100 50 Fn N T C Fn with 4kg load Fn with 8kg load error Fn 4kg load error Fn 8kg load Polynomisch error Fn 4kg load Ill 32 Fn error in function of the oven temperature corrected normal force in function of the oven temperature Fn N oven temperature C corrected Fn measured Fn error Fn Ill 33 Corrected Fn in function of the oven temperature Damian Frey High Temperature Tribometer Simon W est 25 69 ni Fachhosteschule Mortersotector a EMPAQ Hoahestule f r Tanh nik Materials Science amp Technology 4 5 4 2 Dynamic torque Analog Input 1 high temperature dynamic torque To calculate the tangential force from the dynamic torque M the diameter of the ring sample is needed characteristic curve M 0 1 2 3 4 5 6 U V
52. ompensate the normal force error in function of the oven temperature some more measurements are necessary A program to record the normal force error in function of the oven temperature can be found in the tool tab of the LabVIEW start program start vi After recording a formula can be calculated either with Microsoft Excel or MATLAB The formula can be added in the settings tool tab of start vi 8 4 Fixation of the oven temperature sensor To guarantee a reproducible measurement of the oven temperature the oven temperature sensor must be fixed It can be done with a small tube where the sensor could be inserted The small tube must be fixed somewhere at the heating shield or the force lever 8 5 Mechanical damping of the motor support Due to the characteristic frequencies of the motor as shown in Ill 17 it is advisable to damp the motor support with an additional construction Ill 65 Example for an additional support 8 6 Alignment of the rotating arbor We aligned the motor arbor the dynamic torque sensor and the driven arbor with the ring sample as precise as we could but a machinist could surely do that more precise The support of the motor allows aligning them in every direction 8 7 Test security coupling We could not test if the security coupling really separates the drive train from the motor if the torque exceeds 7 5 Nm It is already tested by the company Mayr www mayr de but to be sure an overload test could be d
53. one by manual overload Damian Frey High Temperature Tribometer Simon W est 63 69 nc pridie en d Materiais Scienco amp Technology 8 8 Cover for the rotating elements security To increase personal security and according to the guidelines of SUVA all rotating elements must be covered Therefore it is advisable to construct and install a cover similarly to the one which was installed before IIl 66 Old cover of the rotating elements 8 9 Oil leakage Unfortunately the oil feed system of the rotating arbor is leaky At high rotation speeds some oil is dripping into the oven chamber We could not exactly locate the leakage but assume the oil pump presses the oil through the bearings Ill 67 Oil in the oven chamber Damian Frey High Temperature Tribometer Simon Wiiest 64 69 n TERTII EMPAQ AA Hegheshule f r Technik Materiais Scienco amp Technology 8 10 Test the reliability of the tribometer We could not afford to test the reliability of the tribometer profoundly until the end of the diploma project This is of interest especially for long term experiments 8 10 1 Counter problems While running longer experiments we discovered some problems with the counter e The counter stopped counting which sets the measured rotation speed to zero Due to this the Distance is not increasing anymore and the experiment runs continuously even if the programmed distance is reached By now we do not
54. ontained the development of different solutions which allow measurements in room temperature and high temperature experiments For the determination of empirical friction coefficients of different material combinations the normal force and the friction force must be measured in experiments Further the temperature and the rotational speed must be measured and regulated at the same time In the sixth study term including the diploma work the solution confirmed by EMPA was implemented and the tribometer was taken into operation Finally some test experiments were done to verify the tribometer This text is partly similar with the text from the documentation of the first term project Damian Frey High Temperature Tribometer Simon W est 1 3 n LU Fochhocheslinle Hordzsectechsseiz MA Hochschule t r Technik Materiais Scienco amp Techn logy Customer Dr Johann Michler Empa Werkstofftechnologie Feuerwerkstr 39 CH 3602 Thun Email Johann Michler empa ch URL www empa ch Project team Damian Frey Email damian frey O students fhnw ch URL www damianfrey ch Supervisor Prof J rg Sekler Hochschule fiir Technik Steinackerstrasse 5 5210 Brugg Windisch Email joerg sekler fhnw ch URL www fhnw ch Coach Prof Martin Kl ti Hochschule f r Technik Steinackerstrasse 5 5210 Brugg Windisch E Mail martin kloeti fhnw ch URL www fhnw ch Mousab Hadad Empa Werkstofftechnologie Feuerwe
55. or further analysis Optionally a software tool can be programmed which already preprocesses the routine analysis work In a final phase of the project various experiments will be run on the machine Particularly specimens with micro and nanocomposites and coatings are of special interest Damian Frey High Temperature Tribometer Simon W est 5 69 n TERTII EMPAQ AAA Hoahestiule tr Technik Materiais Scienco amp Technology 3 Tasks and solutions 3 1 Tasks The main tasks to be solved are listed below 1 Temperature regulation The temperature in the test chamber or the sample temperature is to be regulated by LabVIEW Either a constant temperature usually or a desired ramp is given Rotation speed control Until now the rotation speed was controlled manually An automatic regulation of the rotational speed is preferable Arbor torque and rotational speed measurement The dynamic torque as well as the rotational speed at the arbor which rotates the ring sample are to be measured and plotted by LabVIEW Torque measurement at the lever The static torque at the lever which presses the block sample onto the ring sample is to be measured and plotted by LabVIEW LabVIEW program and user interface The LabVIEW program has to acquire all measured data and write them in a csv file which allows interpreting the data with Microsoft Excel or a similar program Furthermore it should be possible to program different e
56. perature Tribometer Simon W est 11 69 Ill 14 Parts measuring physical values The measuring parts are shown in light green From left to right Normal force friction force torque sensor rotational speed encoder For additional security we installed a security coupling EAS compact Type 01 493 530 0 from mayr Kupplungen AG www mayr de shown in Ill 16 instead of the coupling between the dynamic torque sensor and the motor It protects the dynamic torque sensor from being destroyed if an unexpected blocking either of the motor or the arbour occurs If the security coupling separates the drive train from the motor a contactless end switch Type 055 001 5 230 V AC detects the stroke of the security coupling and sets LabVIEW Digital IO 6 to low Damian Frey High Temperature Tribometer Simon W est 12 69 nit focal Narcea EMPAQ s chulo f r Tauhinik Materiais Science amp Technology 4 1 2 Characteristic frequencies During the first experiments we realized that the motor support starts to vibrate at distinct frequencies of the motor We could borrow a gravitation sensor We mounted it onto various parts of the tribometer and recorded the vibration in relation to the motor speed The sensor records the acceleration in x y and z directions Be aware that this diagram does not show the amplitude the distance but the acceleration of the sensor The x y and z directions are those of the sensor not of the tribometer
57. perature normal force with room temperature force module 27 Ill 37 Calibration of the room temperature normal force essere rennen 28 Ill 38 Characteristic curve room temperature normal force esee 28 Ill 39 Calibration of the room temperature tangential force seen 20 Ill 40 Characteristic curve room temperature tangential force eeneeeeeeee 20 Ill 41 User interface to create a program step ua sasaa aaa 32 Ill 42 User interface to create a simple program eseeseeeseeeeeeeeneeneen nennen nennen 33 Ill 43 User interface to simulate a program nnne 34 Ill 44 User interface to run an experiment nennen rennen nennen nente nenne 36 Ill 45 User interface of the temperature measurement server eene 37 111 46 User interface to adjust the settings na aan 38 Ill 47 User interface to test the settings aw 45 Ill 48 User interface to evaluate the idle torque eeieteeeeneneneoeneoeneeenneonneneneneneeeneeenee ei 46 Ill 49 User interface to evaluate Fn T ooooococnnococcccnoooonncnonannncnnnnnnnconnnnnonnnnnnnncnnnnn nn ener 47 Il 50 Report high temperature experiment www wasakwa ensen eieiei seeiis 52 Ill 51 Friction coefficient as a function of the distance 0 eee ees eeeeeseeeseesseeeseeseaeseseeseeeeeseeeeeaeeees 53 Ill 52 Temperature ABA iio died 53 Ill 53 Report room temperature ex
58. periment essere nnne rennen 54 Ill 54 Friction coefficient as a function of the distance room temperature esses 55 11 55 Temperature diagram room temperature essere ener een rennen 55 Ill 56 Diagram with different sampling rates at 500ms saving rate eee 56 Ill 57 Diagram with different sampling rates at 100ms saving rate eese 56 Damian Frey High Temperature Tribometer Simon W est 68 69 n LU Fachhochschule Nordvesctechven EMPAQ MA Haghestule t r Tashnik Materiais Scienco amp Technology Ill 58 Diagram with different saving rates at 2ms sampling rate eese 57 Ill 59 Diagram with different saving rates at 100ms sampling rate eene 57 Il 60 Regulated oven temperature emieteenereneneneneneneneneneneennneoeneoeneoeneeenneanneeneneneeeneeenee ei 58 Ill 61 Regulated sample temperature nnne erem nison nennen rennen 58 Il 62 Partly melted filament sese rennen neret arc emen enne 59 Ill 63 Buckle in the oven tube 12 November 200 7 ccce nennen nennen 60 Ill 64 Ceramic heating element from PROBAG W rmetechnik eene 62 Ill 65 Example for an additional support nennen anna nn ran nennen 63 Ill 66 Old cover of the rotating elements eese nnne nennen nente nnns 64 111 67 Oil in the Oven chambet
59. r will be passed directly onto the torque sensor An elastic element could filter out the motors vibrations As described above we do not want to use elastic elements because their behavior and the impact on the system are difficult to predict If vibrations form the motor should be a problem the motor can be decoupled from the torque sensor with a rotating mass between the motor and the torque sensor With an additional mass the system will lose some of its dynamics This is not further a problem since the experiments are run at a constant rotational speed The last solution described above is schematically drawn in Ill 11 The motor indicated in dark green is mounted directly to the torque sensor Since the motor will be controlled with a frequency converter the various gear is not needed anymore Because of the missing gear the motor will turn considerably slower than before for a long time The motor is self cooled so the possibility of overheating is quite high To avoid heat damage to the motor a separate ventilator is installed which will guaranty constant air cooling force lever couplings motor G g E torque sensor oil feed Ill 11 Schema of the new system The rotational speed of the arbor is measured with a rotary encoder also indicated in light green The encoder is driven synchronously with a toothed belt from the arbor Since this construction will overlap the size of the current tribometer quit a bit an a
60. rials Science amp Technology 4 5 5 2 Tangential force Analog Input 3 room temperature tangential force Ill 39 Calibration of the room temperature tangential force Carrier frequency amplifiers channel 1 settings for calibration e Set the basic parameter of the measuring range to 1 mV V e Set the output voltage to 0 0 V with the unloaded module R balance e Note that the modulation must not exceed the critical level with maximum load C balance characteristic curve Ft2 140 00 120 00 100 00 80 00 Ft2 N 60 00 40 00 20 00 0 00 0 000 0 500 1 000 1 500 2 000 2 500 3 000 U V measured tangential force calculated tangential force Ft2 44 60995 U 0 01965 Ill 40 Characteristic curve room temperature tangential force Damian Frey l High Temperature Tribometer Simon W est 29 69 n iU Fochhoshectinls Horlvzertecheyen EMPAQ SK Hochschule t r Toonnil Materiais Scienco amp Technology 4 5 6 Temperature measurement Temperature Channel 02 gt sample temperature Temperature Channel 03 gt oven temperatures Temperature Channel 04 gt strain gauge temperatures Temperature Channel 05 gt dynamic torque sensor temperatures 4 5 7 Analog output 4 5 7 1 Filament heating control Analog Output 0 control input dimmer The control input of the dimmer 0 10VDC sets the heating current 0 16A which determines the heating power 0
61. ribometer 5 3 4 1 Idle torque as a function of the rotation speed When the tribomter is run without any load a torque can still be measured This torque behaves as a logarithmic function to the rotation speed The software can correct this idle torque It basically evaluates the speed with a given formula and subtracts this value from the measured torque The new corrected torque is then saved to the data acquisition file To determine this logarithmic formula an extra tool is available This application scans trough the range from zero to the maximum output of the speed signal in discrete steps The resolution is determined by the number of steps and the range For each step the frequency of the motor in rounds per minutes and the idle torque is measured From these two values the corrected idle torque is computed with the correction formula as well This value should be as close to zero as possible and is equivalent to the measuring error All three values are saved to a csv file refer to Ill 35 Ill 48 User interface to evaluate the idle torque Damian Frey High Temperature Tribometer Simon W est 46 69 n ue Fa la Horsiyeentechesen EMPAQ F Hohe rEschnil Materials Science amp Technology 5 3 4 2 Normal force as a function of the temperature The normal force falls with the rising temperature due to the thermal expansion of the geometry The software can correct this behavior It basically evaluates the oven
62. rkstr 39 CH 3602 Thun Email Mousab HadadO empa ch URL www empa ch Simon W est Email simon wuestO students fhnw ch URL tech wueest name Damian Frey Simon Wiiest mM 3 High Temperature Tribometer Materiais Scienco amp Technology n TERTII EMPAQ AAA Hoahestiule tr Technik 1 Content MEC Du kala ta 1 PZEM onse pn Henne 4 2 1 Initial situation uio cei dd 4 2 2 uri EN 5 2 2 1 Achieved first term project goals nene nennen rennen 5 2 2 2 Second term and diploma goals eese ener nennen 5 3 Tasksand solutions etae e Lp ee E Ree ede ee Pate OE RD eds EGRE GENS De EUR Foe cg 6 3 1 JE SM Pn 6 3 2 sinu M MQH O O ERR 7 3 2 1 Temperature eu eei petente een 7 3 2 2 Rotation speed control sees enne nennen tenente nne ener enne 7 3 2 3 Arbor torque and rotational speed measurement eese 8 3 2 4 Lev rtorque i i tii btt 8 4 Ihe new Lnbometer iere eie eir des e ee eee Pi dai 9 4 1 MEGM MIGS E 9 4 1 1 A eere rire e E ee EE aod Dre dE ERR a 9 4 1 2 Characteristic JUS cay metere eret Trete de Hae pie eig dis 13 4 2 Electi CS A avant 15 4 3 aa a NO 16 43 1 Power clrcU lidad ia 16 4 3 2 Signal UA UE KHA el AL an t KT EEANN i 16 4 3 3 AA TO 17 434 Darlington dryer
63. rom the motor onto the arbor One possibility is to keep the motor in the support where it was and bring the radiation over V belt or a chain and a rather complicated redirection device to the arbor With this solution it will be very complicated to predict the behavior and to determine the characteristic frequencies because the rotation and the forces are passed through many parts Ill 10 Schema of the old system The idea to solve this problem is to simplify the system as much as possible A more simple solution than the one described above is to extend the arbor of the motor so it will reach the outside of the support through a hole From here the rotation can be brought directly to the torque sensor over a V belt or a chain since we now got enough space to get behind the torque sensor with a belt The problem with belts and chains is that their elastic behavior is difficult to determine and to predict To V This text is partly similar with the text from the documentation of the first term project Damian Frey High Temperature Tribometer Simon W est 9 69 hh nc o avoid elastic behavior we could use stiffer parts e g gear But there again these parts have backlash which are also not wanted in our system The simplest solution is to mount the motor directly to the torque sensor This way we can avoid complicated behavior in characteristic frequencies The downside of this solution is that vibrations of the moto
64. rough the program step by step until the program is done See 5 3 2 1 for more details 8 The window with the header information for the report pops up again The user may adjust the previous entered information or provide new information like the samples weight after the experiment 9 Finally a HTML report about the experiment is created It contains all relevant information e Experiment and sample information provided by the user e The program which was run e The software settings at the time the experiment was run e The machine protocol which was created during the experiment e Some rough graphs from the temperature the speed and the friction coefficient e A link to the csv file with the acquired data Damian Frey High Temperature Tribometer Simon W est 35 69 Sample temperature Speed m s 178 3 2 940 0 D T D D DO true temp PAYA true speed PY 00 00 00 00 00 20 00 00 40 00 01 00 00 01 20 00 01 4 target temp MN Time target speed NR Time Step no Step name _ Temperature C Speed m s Time s Distancefml__ Speed up 3 000 EE e Hold 5 000km EXI p Slow down u e CS ENS o 8 4 x Pa 403 f 400 600 A 10 50 2 Remaining 200 800 Remaining J time 4 gt distance K 60 o 100 4 gt 0 00 P 4 72E 3 irl Data acquisition Overheat protection Ill 44 User interface to run an experiment 5 3 2 1 Control and a
65. stance is shown Simple program Ill 42 User interface to create a simple program Damian Frey High Temperature Tribometer Simon W est 33 69 ech EMPAQ Materiais Scienco amp Technology 5 3 1 2 Simulation To check if the program actually does what it is supposed to it can be simulated A numerical simulation of the tribometer can simulate the expected temperature speed and forces Expect for simple program it is recommended to simulate programs prior using them for experiment Simulation Simulation 700 Sample 6004 temperature 400 Speed m s 200 gt 0 623 2 2 887 i T 1 i truetemp PY 00 205 00 10 00 00 15 00 00 19 34 true speed PY 00 00 05 00 00 10 00 00 15 00 00 19 target temp MEN Time _target speed EN Ine Torque Nm 5 1 D 1 00 10 00 00 15 00 00 19 3 05 00 15 00 00 19 Time Major error Temperature Speed amp Distance Room temperature force module Current step program Program Rates Current Errors Acceleration Distance m 887 23 1750 5 Diameter m 2000 0 040 22507 2500 2750 3000 gt N 1378 Data acquisition Overheat protection Ill 43 User interface to simulate a program Damian Frey High Temperature Tribometer Simon W est 34 69 nic Fachhosteschinle Hordvseteoleeeiz EMPAQ Hoahestule tr Terri 5 3 2 Run an experiment The software
66. stem adds a new data point to the charts on the GUI This value should not be chosen to high since updating the GUI to often uses to much CPU time The rate in milliseconds how often the system updates the current 5 minutes 500 ms 2 000 ms Damian Frey Simon W est High Temperature Tribometer 39 69 Materiais Scienco amp Technology Variable Current measuring period Kp temperature controller Ki temperature controller Kd temperature controller Kp speed controller a Q E S 3 a vo S z q Q Ki speed controller Kd speed controller Description Default value The period in milliseconds in which the system 50 ms measures the current Since an alternating current is measured an RMS calculation needs to be done over this measuring period The RMS calculation will be more accurate if this value is high This value should not be too high since it blocks the other task of the system during that time The temperature controller works with a PID controller 1 which is defined as follows y t Kp e t Ki int e t dt Kd diff e t dt This value defines the proportional term Kp of the PID controller The temperature controller works with a PID controller 1 which is defined as follows y t Kp e t Ki int e t dt Kd diff e t dt This value defines the integral term Ki of the PID controller The temperature controller works with a PID
67. t new devices or parts have to be build or bought On the basis of this analysis several solutions have been developed For each solution the advantages and the disadvantages as well as the effort in terms of cost and labor were estimated A preliminary estimation of the required budget has been made available before the end of 2007 After the presentation of the different solutions we got clearance to buy the required materials and started implementing the selected solution 2 2 2 Second term and diploma goals The entire tribometer has to be reassembled Additional sensors have to be integrated into the system which will allow measuring the temperature near the probes the friction force the normal force and the true rotation speed of the probe ring All experiments should be controlled from a single user interface in particular turning on and off the motor to rotate the probes and the heating of the oven The temperature has to be controlled automatically This includes monitoring the temperature for eventual excessive overheating problems and emergency shut downs as well The interface should allow the user to program temperature changes during the experiment e g linear increase of the temperature form 20 C to 700 C A control for a preselected rotation speed has to be installed as well The gathered data temperature friction force normal force rotation speed have to be protocolled and stored automatically so they can be used f
68. ted to the LabVIEW data acquisition card with one single cable Ill 21 Interface terminal box To prevent the tribometer from damage some security features are implemented by the hardware e tis not possible to start the motor without the oil pump running S3 e tis not possible to heat up the oven without water cooling turned on S7 The denomination numbers of the parts in the electrical schema are not always progressive because we did not renumber the parts after the modernization Some parts have kept their denominations from the old schema Damian Frey High Temperature Tribometer Simon W est 15 69 EMPAQ Materials Science amp Technology nic cs 4 3 Schema ARAN y pitt MEA RELATA PAS E ME 11 17 mn 1 nr N damd 4 ES heed EET ETTE FERE 1 LITT Ill 22 Power circuit AT tt Ill 23 Signal circuit Damian Frey Simon Wiiest 16 69 High Temperature Tribometer ls Hordveectechyvetz EMPAQ chnik Materials Science amp Technology nic 4 3 3 Current measurement HHHH multiplexer current measurement 4 3 4 Darlington driver Hie i f 4 3 5 Terminal block frequency converter A EEE L ent aas 642293 e
69. temperature with a given formula and subtracts this value from the measured normal force The new corrected normal force is then saved to the data acquisition file To determine this formula an extra application was created It basically heats up the tribometer with the maximum heating power and continuously measures the temperatures and the normal force For each temperature update received from the temperature measuring remote computer a set of data is saved to a csv file refer to Ill 32 Ill 49 User interface to evaluate Fn T 5 3 5 Data management system The programs and the experiments can be managed in the data management system This application acts also as a home interface From here all above described applications and tools can be called The programs must be all saved in the same directory and each program has to be in a separate folder This application will scan through the directory and list all the found programs The experiments are organized in dossiers and experiments Each experiment belongs to one dossier The dossier and the experiments both have a unique number When a new dossier or experiment is created the dossier and experiment numbers are automatically assigned Damian Frey High Temperature Tribometer Simon W est 47 69 n lut Fasbihoslictnls Horlvzertecheyen EMPAQ Hashestiula f r mik Materiais Scienco amp Technology 5 4 Main VIs In the following table the main Vis are listed They can
70. that is why the offset of the measured acceleration g is not equal in the diagrams characteristic frequencies measured on the motor 0 5 uti LAM TAB y NW it AM il a g tal 0 peca ty TILGA i TT IA TW VIA NEN n n 0 500 1000 n rpm x yYy z 11 17 Characteristic frequencies of the motor characteristic frequencies measured on the dynamic torque sensor 1 A minemata JA M ANT Hl li T JL MT AA i N POSTA 3 Mi aM n p en Teri a 2 3 EN n rpm ry z Ill 18 Characteristic frequencies on the dynamic torque sensor Damian Frey High Temperature Tribometer Simon W est 13 69 characteristic frequencies measured on the electric control box 0 5 a g N CPC 07 heute LIE um Make ii 3000 M VN NM Yr NET TA UN MAN N Wm p from WI uen n rpm x y z Ill 19 Characteristic frequencies on the electric control box characteristic frequencies measured on the oven tube 14 1 2 0 8 0 6 0 4 a g 0 2 WW LN Lui Luv main uod u 0 2 0 4 Ht 0 6 n rpm
71. to be connected to the motor Several frequency converters have an input ratio between 0 and 10VDC so they easily can be controlled with LabVIEW For this solution a rotational speed feedback is required see 3 2 3 The maximum acceleration is limited by the settings of the frequency converter see user manual Advantages Disadvantages e Rotational speed control with LabVIEW e Costs about 750 CHF e Possible to change rotational speed e Another consumer of electricity during an experiment e g ramp 000 L200 A WARNING Ill 5 Frequency converter Hitachi L200 Damian Frey High Temperature Tribometer Simon W est 7 69 nic o Materiais Scienco amp Technology 3 2 3 Arbor torque and rotational speed measurement The dynamic torque is detected with a dynamic torque sensor without rotation speed sensor The rotational speed is detected with an incremental encoder Advantages Disadvantages e Torque can easily be detected and e Additional support for the torque sensor evaluated with LabView and the incremental sensor has to be e Rotational speed can easily be acquired constructed with LabVIEW e Rather expensive T22 from HBM ca 4 050 CHF Ill 6 Dynamic torque sensor Ill 7 Incremental encoder 3 2 4 Lever torque As we dismounted the lever which presses the block sample against the ring we realized four strain gauges were already applied to the arbor They did not work anymore because the strain gaug
72. trol the current of the heating element We bought a replacement dimmer from the company se Lightmanagement AG With the new dimmer the heating worked correctly again 7 2 2 Heating element filament As we tested the heating in a regular high temperature experiment we noticed that the temperature could not be kept on 700 C It steadily decreased during the experiment As the experiment was finished and the oven cooled down we opened the chamber and realized that the heating element was partly melted shown in Il 62 Ill 62 Partly melted filament We looked for different solutions but at first we did not even know what type of filament it was We asked several companies for a replacement but the extreme temperature conditions and the high power density W mm turned out to be difficult parameters An exact replacement of the filament turned Damian Frey High Temperature Tribometer Simon W est 59 69 n w kin EMPAQ A Haghechule f r nik Materiais Scienco amp Technology out to be expensive We got an offer about CHF 1200 from the company Thermocontrol GmbH in Dietikon ZH The filament is a standard product of THERMOCOAX a company in France This filament is only for temperatures up to 600 C and for powers up to 1 5 kW To reach temperatures up to 700 C another heating element would be required At last we decided in agreement with the customer to find a solution after the diploma work for example in a
73. ubtracted from the measured torque in Nm correction value Nm f frequency of the motor rpm The measured signal x in volts will be evaluated with this formula The result is interpreted as a normal force with the real world unit Newton With the rising temperature the normal force falls due to thermal expansion of the geometry The software calculates with the oven temperature in C and this formula a correction value This value is subtracted from the measured normal force in Newton correction value N f oven temperature C The measured signal x in volts will be evaluated with this formula The result is interpreted as a normal force with the real world unit Newton This formula is used instead of the above formula when the room temperature force module is installed The measured signal x in volts will be evaluated with this formula The result is interpreted as a normal force with the real world unit Newton This formula is used for the normal force channel of the room temperature force module The measured signal x in volts will be evaluated with this formula The result is interpreted as a friction force with the real world unit Newton This formula is used for the friction force channel of the room temperature force module The measured signal x in volts will be evaluated with this formula The result is interpreted as a current with the real world unit Ampere Default value 6003 60
74. updates the current temperature and sends the new values over TCP to the main program The server application can be controlled start stop measuring and configured from the main program also over TCP Since updating the cold junction sensor needs a lot of time and the cold junction sensor is fairly stable it is updated at a much lower rate than all the other temperature channels emperature Measurement TCP server 10 196 178 119 Pe E Ill 45 User interface of the temperature measurement server 5 3 2 3 Errors and machine protocol For each experiment a machine protocol is created All major events for example when a new program step is loaded and errors are saved to this protocol Protocol entries and errors from the remote temperature measuring computer such as cold junction sensor updates are also sent over TCP to the main program Each entry in the machine protocol has a timestamp and a short message In the main application an extra thread listens for machine protocol entries and errors from the remote computer Damian Frey High Temperature Tribometer Simon Wiiest 37 69 n iU Faesbihosliectnls Horlvzertecheyen EMPA Hesheshubs A Marl is Science amp Technolo Xy 5 3 3 Tools to adjust and calibrate the software The software uses a series of setting and parameters Before an experiment is run these settings are loaded from the default configuration file The user may adjust these settings to optimize the tri
75. valuated with this formula and the result is interpreted as control signal in volts Default value 50 Hz 25 Hz 10 V 500 15 5 A 15 A x 1 6 Damian Frey Simon Wiiest High Temperature Tribometer 44 69 tote EMPAQ Materiais Scienco amp Technology 5 3 3 1 Test the settings To test if the adjusted settings are reasonable a separate tool is available This tool works just like the experiment executing program except that it loads no program The user can set a target temperature and a target speed and let the software start and stop saving data to a dummy file The tribometer then tries to follow the target values The measured forces temperatures speed and update rates are shown in real time on the GUI so the results of the adjustments are directly visible P Test settings Temperature Speed Forces Rates Current Errors T Control OS Speed m s truespeed PY target speed PY Oven temperature Speed m s 07 1 1 1 1 1 1 1 1 00 00 00 00 00 30 00 01 00 00 01 30 00 02 00 00 02 30 00 03 00 00 03 50 Ji Data acquisition Temperature control c Sample temperature Time Distance m 1200 38 Diameter m 10 040 Motor mode Ill 47 User interface to test the settings Overheat protection Machine running Damian Frey High Temperature Tribometer Simon Wiiest 45 69 ae EMPAQ n 34 e Heshechule 5 3 4 Calibrating the t
76. w data and more diagrams Experiment report 000000008 Example experiment Created on Donnerstag 14 August 2008 12 31 57 General Customer EMPA Operator Simon W est Dossier Nr 000000001 Experiment Nr 000000008 Name Example experiment Description An example experiment for the documentation Oven temperature 200 C Speed 3 m s Distance 5 km Sample Material Density Diameter Initial weight Post experimential weight Weight loss Volume loss Wear rate Cleaning Manufacturer Note Lubricant none Lubricant mass 0 000000 g Lubricant application Atmosphere air Load 80 000000 N Fn 245 791004 N Distance 5016 392357 m Note none Block Steel 7 800000 g cm 3 100 000000 g 98 000000 g 2 000000 g 0 256410 cm 3 2 079591E 4 mm 3 N m none EMPA none Ring Steel 7 800000 g cm 3 40 000000 mm 200 000000 g 197 000000 g 3 000000 g 0 384615 cm 3 3 119386E 4 mm 3 N m none EMPA none Program settings Program name Standard test program Program description Heat 200 C Speed 3 m s Distance 5 km Control oven temperature Program details Settings Machine protocol Date Time Start time 14 08 2008 11 47 56 End time 14 08 2008 12 31 10 Data Raw data csv Graphs HTML Ill 50 Report high temperature experiment Damian Frey Simon W est 52 69 High Temperature Tribometer n Ww Fechhoeheohuls Nonbesctecheeiz EMPAQ Ho
77. works through the following steps 1 Load the general software settings form the default configuration file 2 Ask the user for the paths to a program and a working directory All information about the experiment and the acquired data are saved in the working directory The working directory can also be provided by the experiment management system See 5 3 5 for more information 3 Copy the program and the configuration file with the settings to the working directory 4 Load the program 5 The header to the report is now created The user is asked to enter various information about the samples and the experiment such as experiment name experiment description sample material sample weight and so on The most important information here is the ring samples diameter It is used to calculate the surface speed of the rotating ring sample during the experiment 6 To ensure a correct startup of the machine a user interface pops up which guides the user through the startup procedure a Install the samples b Configure the remote temperature measuring computer c Switch on the carrier frequency amplifier and test the force sensors d Startup the tribometer until it is fully functional The different switches on the tribometer have to be turned on in the correct order e Test the incremental encoder speed sensor f Test the current sensors g Check if the coupling or the frequency generator report an error 7 Now the software works th
78. xperiments and to simply recall them for repeated use Y This text is partly similar with the text from the documentation of the first term project Damian Frey High Temperature Tribometer Simon W est 6 69 k Materiais Scienco amp Technology n MU oiim EMPAQ Pi d Haghes tor Teil 3 2 Solutions 3 2 1 Temperature regulation EMPA Thun already used a rack for thermocouples from National Instruments Type TC 2190 including the matching DAQ PCI Card We decided to reuse this module because it is easy and accurate enough Two temperature sensors Type K are used One measures the temperature near the probe and the other in the oven environment The temperature signals are acquired by LabVIEW This information should be protocolled and further be used to regulate the temperature in the oven To do so LabVIEW controls a dimmer 0 10VDC which sets the heating current The dimmer already exists Until now the heating current was controlled with a potentiometer Additional temperature sensors are installed as well to monitor the strain gauges measuring bridge and the torque sensor temperature Advantages Disadvantages e Cheap and simple e Old components dimmer is not available e No additive components are necessary anymore if it needs to be replaced Ill 3 Dimmer varintens LE 16 Ill 4 Temperature module NI TC 2190 3 2 2 Rotation speed control For the automatic rotational speed control a frequency converter has

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