RMT Ltd
Contents
1. 3 14 Principle of Figure of Merit Measuring a7 DX4165 RMT Ltd Here the dependence of Z on the temperature was ignored which is quite allowable at the temperature scale considered For instance if Z 0 0027 K and T 300K we have the following temperature difference AT max 70 K 3 3 Theory of Operation a TEC mounted on the heat sink Heat sink means a noticeable increase of heat dissipation through the TEC basement It must be taken into account when estimating the role of this factor in measurement results Equation 3 9 ee 1 by U 5 Ta 1 b Ur averaged emmm 3 8 REV 1 00 2003 RMT Ltd DX4165 allows for heat dissipation through the warm side of TE with the corresponding term br and the voltage averaging So the estimation of the brvalue of the assembled TE module is possible if taking into account thermal properties of the heat sink As a rough estimation we can assume ahs S 3 15 A where ks thermal conductivity of the heat sink Ss surface of the heat sink as the TEC projecting Ls thickness of the heat sink Principle of Figure of Merit Measuring 3 9 DX4165 RMT Ltd 3 4 Theory of Operation Z measuring of a Two stage TEC Hereinafter we deal with the stationary mode values only see Ch 2 The general formulae for a two stage module cold and hot sides are UNE a alT I R k T T TF e Oh 1 N 0 IT2. Fig 5 3 Power On button ee 5 8 REV 1 00 2003 RMT Ltd DX4165 5 6 Measurement of Parameters of TE coolers Before measuring it is necessary to keep the DX4165 Meter and tested TE modules indoor during one hour in the same room where TE modules will be measured This is necessary to even temperature of TE modules and DX4165 Meter Important If the DX4165 Meter was outdoors at low temperature for a long time temperature below 10 C it is necessary to keep Z Meter at room temperature for not less than 2 hours Press the two buttons on the front of the housing Fig 5 4 and open the cover of the DX4165 Meter There are positions for 10 at the most TE modules to measure Each position has four terminal blocks The first two are Fig 5 4 Cover unlock intended for one lead of a TE handle cooler the other two are for the other lead Turn the arm type metal plates and insert each TE cooler leads into those holes that best correspond to the TE cooler size Fig 5 5 The polarity has no meaning as i the coolers are tested by Fig 5 5 TE coolers S bipolar averaging leads insertion Working with Z Meter 5 9 DX4165 RMT Ltd Close the cover and run the Z Meter program The window presented in Fig 5 5 is to be displayed If device is properly plugged in and the program has found it the status bar will show the device ID time Device DX4165 100 found If for so
3. 1 PR k T T e T T k T T T OLE P T 1 Gi gt T where To T T TE module s cold side medium and hot side temperatures respectively N N pellet numbers at the first and second stages If it is possible to assume that the heat transfer coefficient a and the pellets number N are proportional to the corresponding cold side areas S 40 2 A const 3 17 N 1 N 2 el 3 1 0 REV 1 00 2003 RMT Ltd DX4165 and 3 18 equations 3 17 are modified the following way oT RK Dia 1 nit PR K T DI ACT T 3 19 Summing up equations 3 19 we derive 20T k A AT 3 20 rt where T 2 is the average module temperature Solving the following set of equations 2oIT k A AT r Ua Ze apes Uo Uo a N N Principle of Figure of Merit Measuring 3 11 DX4165 RMT Ltd we obtain the following Ua ZT 1 by 1 6 ji 3 22 UR b B oond Agony Brad Ay 3 23 The parameters Beona Braa are described above 3 4a 3 4b al 2 3 24 conv KB A pad of 3 25 ra xB where Aconv Arad Stand for convection and radiation The problem stated by eq 3 16 is polarity symmetrical So the averaging of the different polarity voltage ratios for accuracy concerns is appropriate So eq 3 22 can be rewritten as _ U ZT 1 b 1 5b amp wat d U L 3 26 Knowing the Z value we can eva
4. Principle of Figure of Merit Measuring 3 5 DX4165 RMT Ltd Correction factor to pellet thermoconductivity due to Beond Brad 3 9b additional heat flux from the fa Beond Brad 3 95 warm side to the cold one through the medium according to 3 2 Correction factor because of 3 9c a non zero resistance of TE module wires RTEC where Rrec NR The total voltage drop Uris a sum of the drop Urec at the module and some additional drop at terminal wires ris their resistance so Uk I Rrec r IRrgc 1 b 8 10 UR UR Gb 3 11 Due to the above formulated correction factors eliminate the effect of actual arrangement of Z metering technique on the Z value and allows to estimate the true material Figure of Merit nl 3 6 REV 1 00 2003 RMT Ltd DX4165 3 2 Figure of Merit and ATmax for Single stage TEC The Zvalue corresponds to the maximum temperature difference on a module AT by 3 simple ratio AT max 52T 3 12 However the direct measurement of To is complicated Amore convenient way is to measure the temperature TT AT max If the heat sink thermal resistance is little the hot side temperature approaches the ambient temperature and T x T is used instead of 77 Hence there is the following equation for AT max 1 AT max S E ma 3 13 Then it is easy to recalculate the value ATmax aS a function of the ambient temperature J7297T 4 AT max Ta Ta Z
5. Tmax Time Constant Using DX4165 Z Meter it is possible to perform testing of various types of single and two stage TE modules Additionally it is possible to evaluate quality of three or more stage TE modules by the measurement of electrical resistance Although the above listed parameters are measured at ambient temperature the DX4165 Z Meter provides recalculation of them to any standard temperature 20 C or another software selectable The DX4165 Meter is managed by any IBM compatible computer under Windows 98 2000 XP operating system Introduction 1 1 DX4065 RMT Ltd ee 1 lt 2 REV 1 00 2003 RMT Ltd DX4165 2 Principles of Time Constant Measuring 2 1 Theoretical Grounding Let us consider a one stage thermoelectric cooler TEC The ambient temperature is 7 At a certain moment the electric current in the TEC is turned on The differential equation result for the TEC transient dynamics can be presented as the following exponential superposition AT t x S U x e AT x 2 1 i l where AT t x T T T is the temperature of the TEC point located at a time and a generalized coordinate x Un and m are the eigenfunctions and eigen values An are the thermal amplitudes AT x is the stationary result value The solution 2 1 analysis yields that the cooling process can be divided into two stages irregular and regular The first one is dictated by the ini
6. with software RMT CD DX4145 User s Manual aR Go h A Steck eet ect eet e 7 1 REV 1 00 2003 RMT Ltd 8 DX4165 Specifications Measured Parameters Electric Resistance Range Accuracy Repeatability Figure of Merit Range Accuracy Repeatability Time Constant Range Accuracy Repeatability Supply requirements Voltage AC Frequency Voltage DC Power max Operation Conditions Temperature range Relative humidity Mechanical Dimensions Weight max Specifications DX4165 Units Value Ohm 0 1 100 0 6 but not better than 0 010hm 0 3 K 1 3 x 10 1 5 0 4 s 1 30 1 5 1 V 85 264 Hz 47 440 V 120 370 W 15 Se 0 45 0 95 mm 204x96x542 kg 3 2 DX4165 8 2 RMT Ltd REV 1 00 2003
7. 165 Ambient selected TE module number is then ROn identified by the green color e Corrections Coefficient field includes calculated corrections values see Chapter 3 It allows to switch a certain correction ON or OFF As an alteration it provides the corrections compounding into a general coefficient a see Formula 3 28 Corrections Default 1 07560 C Manual 1 lv Inter pellets input 0 05778 or Iw Joule heating 0 00036 Iw Leading wires 0 01822 For this coefficient determination it allows to choose one of the three following approaches Default Using the corrections calculated in the corrections field Manual Using a User s own coefficient value None Using neither corrections nor coefficients at all Working with Z Meter 5 17 DX4165 RMT Ltd e Results field contains measured calculated results for all the 10 positions 1 TEC electric resistance 2 Ambient temperature 3 TEC Figure of Merit via two polarities and averaged 4 TEC maximum delta temperature via two polarities and averaged 5 TEC time constant via two polarities and averaged mbient T C 19 8 Ohma Tia DO Ber K la Trae K um KC omg CH Mm KC Heng sec Kerg sec Toonst sec 1 124 6600 60 6640 23 261 259 D i 0 62 0 62 125 6270 634 63 10 2 36 24 238 062 0 62 0 62 129 om Ou o 2 8 241 239 062 062 062 122 6470 6560 65 20 24 2 53 25 0 62 0 62 0 62 133
8. 2 0 62 D 12 122 6510 6640 6580 2 50 2 58 254 0 62 0 62 0 62 13 14 OI TZ Working with Z Meter 5 13 DX4165 RMT Ltd e Options LL Resistance mode allows measuring TE module resistance only Y Options Help TEC base allows selecting a TE ze E alt ode modules data base of a TC TEC Base manufacturing company d Cooler type J Cooler type allows selecting a type 5 of a system to be measured v Auto Save History single stage TE module v Auto Add to History single stage TE module ina Auto Load Tecs Settings housing two stage TE module Auto Save History allows saving a TE module s measurement history automatically After your exiting the program the history is automatically saved in the directory History The file name is formed from the current date and time Auto Add to History allows automatically adds the measurement results to the history Auto Load TECs settings automatically loads saves the measurements settings the electric current frequency and measurement time for each measured TE cooler e Help The option allows to derive the information concerning Z meter program 5 1 4 REV 1 00 2003 RMT Ltd DX4165 5 7 3 Reference Bar There are two fields in the Reference bar Cooler type ID Default ip EE E 00 ai Options Help o beleide Coder ID p typ o SEE ID in the Reference bar is Fae Keiegiie
9. 6090 670 6130 2 230 228 062 062 062 124 6490 6520 65 10 2 49 251 250 0 62 0 62 0 62 LA 6220 6230 Ou 23 235 234 062 062 062 124 6310 6360 6330 2 39 241 240 0 62 0 62 0 62 126 6620 6730 6680 237 2 64 261 0 62 0 62 062 10 124 6390 6590 6490 243 2 55 249 0 62 0 62 062 o9 Of te eB le D 5 1 8 REV 1 00 2003 RMT Ltd DX4165 While TECs are being tested there can be a situation when the TEC line in the Results field is colored red It occurs in two cases 1 The measured TEC has a break in a circuit or a bad contact in its terminals see TEC 1 in the figure below fon Tin Th Elke Po Co KY um Client sec nt sec et sec 1 163 6690 70 50 6870 2 61 284 2 73 327 234 280 2 For large powerful TE coolers at the high current the electric voltage applied to the module exceeds the device constraint In this case there only appears a measured resistance value and the TEC string is red colored see TEC 1 in the figure below Make your measuring current lower and retry the measurement EE 1 163 6690 70 50 68 70 2 61 284 2 73 AN 234 Working with Z Meter 5 19 DX4165 RMT Ltd 5 8 Single stage TEC Z metering To measure a single stage TEC select a Single stage option from the Option gt gt Cooler Type command 5 8 1 Reference The parameters of TE coolers can be measured at various ambient temperatures T
10. 65 RMT Ltd You are supposed to see the pre resulting window Go on to the Next to the finishing one Found New Hardware Wizard Driver Files Search Results age The wizard has finished searching for driver files for your hardware device tn The wizard found a driver for the following device a Z Meter Model DX4165 Windows found a driver for this device To install the driver Windows found click Next SS d work ftdi chip eeprom d10504 ftd2xx inf Found New Hardware Wizard Completing the Found New Hardware Wizard FTDI FT8U2 X Device Windows has finished installing the software for this device Cancel l The hardware you installed will not work until you restart your computer To close this wizard click Finish Bach Cancel Click on the Finish button Note In different WINDOWS OS the USB drivers installation may slightly differ The examples given here are based on the Windows 2000 OS 5 4 REV 1 00 2002 RMT Ltd DX4165 5 3 System Requirements The DX4165 Meter works under the control of the Z Meter program The Z Meter program provides all possible operational modes of the DX4165 Meter The Z Meter has the simple interface and does not demand a User s special knowledge The Z Meter software is delivered with the DX4165 Meter e IBM PC compatible computer with Windows 98 2000 XP operating system e Fr
11. Joint Stock Company 10 position Z Meter TE Module Parameters Meter DX4165 Series User Guide 2003 DX4165 RMT Ltd Edition September 2003 Copyright All right reserved Reproduction in any manner in whole or in part is straightly prohibited without written permission of RMT Ltd The information contained in this document is the subject to change without notice Limited Warranty RMT Ltd warrants that DX4165 Meter if properly used and installed will be free from defects in material and workmanship and will substantially conform to RMT s publicly available specification for a period of one 1 year after date of DX4165 Meter was purchased If the DX4165 Meter which is the subject of this Limited Warranty fails during the warranty period for the reasons covered by this Limited Warranty RMT at this option will REPAIR the DX4165 Meter OR REPLACE the DX4165 Meter with another DX4165 Meter Trademark Acknowledgments All trademarks are the property of their respective owners RMT Ltd 53 Leninskij prosp Moscow 119991 Russia phone 095 132 6817 fax 095 132 5870 e mail rmtcom dol ru http www rmtltd ru REV 1 00 2003 RMT Ltd Contents 1 Introduction 2 Principle of Time Constant Measuring 2 1 Theoretical Grounding 2 2 Interpolation Results 2 3 Theory of Operation 3 Principle of Figure of Merit Measuring 3 1 Theory of Operation Single stage TEC 3 2 Figure of Me
12. d Leads All fields are beforehand filled in with defaults You should enter the true values of parameters in them The contents of cooler ID field are not used for calculations You can fill any information in this field but you had better enter there the manufacturer s brand You can also edit or delete any TEC existing in the TEC base To do it just select the Tec you are interested in make appropriate changes in the data and click on the 5 26 REV 1 00 2003 RMT Ltd DX4165 Add Modify button To remove the TE cooler from the database select it and click on the Delete button Working with Z Meter 5 27 DX4165 RMT Ltd ee 5 28 REV 1 00 2003 RMT Ltd DX4165 6 Maintenance The DX4165 Meter does not require any maintenance or service Nevertheless if for any reason you feel doubtful about the device s accuracy you can check up it by measuring a precision resistor instead of a TE cooler It is best to measure a resistor of 5 to 20 Ohms Ifa precision resistor is not available any other can be used But at first it should be measured with a digital multimeter with the accuracy not less than 3 decimal digits Compare the obtained data If the difference in the resistance values is within 0 5 it is possible to consider the Z Meter serviceable Maintenance 6 1 DX4165 RMT Ltd 7 Standard Kit Item Code Quan Z Meter DX4165 USB Cable Power supply cable CD
13. d Y Nk T 1 B Where o Boltzman constant y thermal emissivity Principle of Figure of Merit Measuring ag DX4165 RMT Ltd At the heat exchange with environment aj r k N 3 5 and the current k I S 3 6 we have 2 a JI Ua _ 7 T I RN A ao 4 Io 3 7 UR dot 2k aot a where Ua Q T To thermoelectric component of the voltage dropout on a TE module the Seebeck voltage Ur IR Ohmic component of the voltage dropout on a TE module poe k R Equation 3 7 contains directly the ambient temperature If using the average temperature we should have allowed for the additional term a 2Nk characterizing heat dissipation from the external surfaces Formula 3 7 takes this term into account automatically via the ambient temperature value ee 3 4 REV 1 00 2003 RMT Ltd DX4165 Consider the equation for Z 3 7 The second term in 3 7 generates a certain correction It is remarkable however that this term is a linear function of the current As a consequence summing the ratios 3 7 measured at different polarities we come to 2 T W i SS ER 3 8 Uz Uri a a That is we managed to solve the problem avoiding any asymmetry correction challenge So the value Z GOAR could be obtained as 1l Ua 1 CD Ta 1 b Ur budX A averaged where 1 PRN Correction factor to ambient b 3 9a temperature due to Joule Tq Ata heating
14. database you can add them yourself To do it you should first of all find out the following parameters of TE cooler es TEC cold size dimensions es The number of pellets for a two stage TEC the pellets number at each cascade TE pellet cross section TE pellet height e TEC wires material e Wire length e Wire thickness If there are no these parameters in the manufacturer s specification you can measure them yourself by means om Options Help pe Resistance Mode heference Trey 200 i TEC Base H e AMT_BASE Cooler type D USERS_BASE After you have prepared all the necessary data select the File TEC Base Editor command from the Working with Z Meter 5 25 DX4165 RMT Ltd Main menu The window titled Add TE cooler will appear as shown below 1MCO04 004 10 1MCO4 004 12 Cooler ID 1MC04 004 15 Cold size dimensions mm v mm IMC04 008 05 Hot size dimensions mm x mm 1MCO04 008 08 SE 1MCO4 008 10 Ceramics thickness mm 1MC04 008 12 Pellets number 1MC04 008 15 TE pellets cross section mm x mm v A One Stage Two Stage 1MCO4 004 08 SC Lape ae TE pellets height mm 1MC04 012 10 1MC04 012 12 Leads 1MC04 012 15 Sg x 1MC04 018 05 Electrical resistivity KE 6 Ohm mm 1MC04 018 08 Length mm 1MCO4 018 10 Thickness mm 1MCO04 018 12 L 1MC04 018 15 There are two input boxes in the window Cooler an
15. ee USB port 4 MB free hard drive space additional space may be required later as your database grows e Mouse or compatible pointing device 5 4 Program Installation The Z Meter program is supplied on a CD Insert the CD into the appropriate drive and start the Setup program The window of the standard Windows installer will appear see the picture below Working with Z Meter 5 5 Setup will install the software to the directory listed in the box below To install to a different directory either type in the new path or click Browse to select another directory Install files to this location CAProgram Files Z Meter Browse Space required on drive 1 9 MB Space available on selected drive 906 MB Cancel Pass all the steps of the installation procedure sequentially according to the installer directions When selecting the logic disk you must keep in mind that the program requires not less than 4 MB of hard disk space As database size increases the additional disk space can be required 5 6 REV 1 00 2003 RMT Ltd DX4165 5 5 Hardware Preparation Turn DX4165 Meter back side to yourself From this side you will find the USB connector Fig 5 1 USB Port Fig 5 1 The back side of DX4165 meter Working with Z Meter 5 7 DX4165 RMT Lta Now you can run the 4 Meter program and measure parameters of TE coolers Fig 5 2 USB Port and Power Connections
16. gieg l a list box for selecting a TE pepi cooler type to be tested The right field Reference T in the Reference bar serves for reference temperature input You may type any reference temperature T directly in the window or increment decrement the current value by 0 1 with the and ei buttons 1MC04 012 15 Besides that you can click the right mouse button inside the Reference T input field The following list must fall down a ail a 20 C 30 C Z Ambient T You may choose one from standard reference temperatures 20 and 30 C or use the ambient temperature as a reference Working with Z Meter 5 15 DX4165 RMT Ltd 5 7 4 Functional Fields There are four functional fields e Control field presents the Seebeck voltage temporal behavior and Z metering input parameters see Chapter 2 1 measuring current 2 total measuring time 3 time step Controls Current mA Measuring Time sec Time Step msec The Measure button starts the measuring procedure e Dynamics field presents the chart window of temporal behavior telemetry see Chapter 2 of the Seebeck voltage Ua t measured and Seeback voltage mv of gg 0 000 76 1 60 2 44 3 28 4 08 4 92 5 76 6 60 7 44 8 28 9 08 9 92 time sec To see the Seebeck voltage dynamics of the selected TE cooler one should choose it in the Results field The D 5 1 6 REV 1 00 2003 RMT Ltd DX4
17. he indications of DX4165 Meter will be varied with temperature See Chapter 3 Principle of Operation Hence measured parameters must be corrected to some reference temperature RMT Ltd uses 30 C reference temperature other manufacturers may use their own values Choose a reference temperature from the Reference T list If there is no required reference temperature in the list enter it manually eel 5 20 REV 1 00 2003 RMT Ltd DX4165 5 8 2 Cooler Type m paons H p ID paas Choose a type of TE cooler to Ele be tested from the Cooler Ge type ID list The list represents le Gabi a TEC base selected via the EOL ee File TEC Base Editor rue command RMT is the default 1MC04 012 10 TEC base 1MC04 012 12 1MC04 25 The following windows reports that one ore more gt fields of the TEC base string selected is are blank a x K Some parameters are missing No corrections will be applied Keep in mind that the TE coolers list is sorted alphabetically If you cannot find the necessary type in the list you should introduce TEC parameters to the database manually See Chapter Database Update If you have no information on parameters of the tested TE cooler you may choose the corrections coefficient default mode and the TEC will be measured excluding any corrections Working with Z Meter 5 21 DX4165 RMT Ltd 5 8 3 Corrections Field Once the mea
18. ist of the known drivers for this device so that can choose a specific driver lt Back Cancel Select the item Search for a suitable driver for my device and click on the button Next 5 2 REV 1 00 2003 RMT Ltd DX4165 2 In the following window remove all the ticks except the one against Specify a location and go on to the Next Found New Hardware Wizard Locate Driver Files ate Where do you want Windows to search for driver files CY Search for driver files for the following hardware device a Z Meter Model DX4165 The wizard searches for suitable drivers in its driver database on your computer and in any of the following optional search locations that you specify To start the search click Next If you are searching on a floppy disk or CD ROM drive insert the floppy disk or CD before clicking Next Optional search locations I Floppy disk drives T CD ROM drives IV Specify a location I Microsoft Windows Update lt Back Cancel 3 Define the driver path The drivers are located on the enclosed CD in the folder SOFTWARE DRIVERS DIRECT Click on the OK button Found New Hardware Wizard Insert the manufacturer s installation disk into the drive E selected and then click OK X Cancel Copy manufacturer s files from Program Files Common Files Logitech QCD rivers Browse Working with Z Meter 5 3 DX41
19. luate ATmax T To finding the maximum of the following function D 3 1 2 REV 1 00 2003 RMT Ltd DX4165 x H AT x fa 37 eee x EE EE SCH where the cascading coefficient dimensionless current 2 zl For instance if Z 0 0027 K and T 300K we have the following temperature difference ATmax 100 K 3 5 Material Z and measured Z Regarding all the correction factors discussed above it is clear that the material Figure of Merit when there is no heat exchange with environment is always higher than the measured Figure of Merit It is convenient to relate the two values via the coefficient a gt 1 Z a Z measured 3 28 Principle of Figure of Merit Measuring 3 13 DX4165 3 14 RMT Ltd REV 1 00 2003 RMT Ltd DX4165 4 Technics 4 1 DX4165 Meter Arrangement The body of the DX4165 Meter is made of an aluminum alloy The metal body executes a function of a passive thermostat for measured modules Temperature of the body is measured with platinum thermoresistor with accuracy not worse than 0 1 C Modules to be measured are placed in this box Simplified Functional Diagram of DX4165 Meter is shown in Fig 4 1 Thermostat Instrumentation amplifier Measuring module 1 Measuring module 10 Collector AC Power Fig 4 1 Simplified functio
20. me reason the program failed to discover the device in the status bar the information Not found will appear til Not Found In this case make sure the device is rightly power supplied and plugging into the PC is correct Check if the USB drivers have been properly installed and rescan the device File gt Rescan Device File History Options Help Rescan Device It TEP D saa Editar ee 5 1 0 REV 1 00 2003 DX4165 Piel 3U9191JJ909 SUO1 91105 MOPUIM ureu urerboid 1ajay 7 ay JO ainjonys pue m n ayy GG BL Punoj 00 L S9LFXd sue seen SEL D das awy V IDasul dag au b s auny Duunspat yw juan jonu Z22810 0 sanm Gupee A E0000 Buneay aop Aj 822500 Ndu Steet Aj O9S20 1 aed 2 Z6 6 80 6 8Z 8 tt Z 09 9 92 S Z6 t 80 t SZ E es 09 1 92 000 0 daH suond AoA ap IL 4979W 2 Dia soiweukg Spel 5 11 Working with Z Meter DX4165 RMT Ltd 5 2 The Main Program Window The main program window is shown in Fig 5 7 Its functional structure is common for three Z meter measurement options e Single stage TEC measuring e Single stage TEC mounted on a header measuring e Two stage TEC measuring This general window includes the following 5 7 1 Menu bar 3 Meter 11 1 0 There are four items in the File Options History Help Menu bar so File Hi
21. nal diagram of DX4165 Meter 4 1 DX4165 RMT Ltd The connection of the modules is made through special connectors For a reduction of the effect of contact resistance the modules are connected under the four wire Kelvin Clips scheme 4 2 AC Resistance Measurement For resistance measuring each module is tested by AC of a small amplitude The AC is simulated with the Commutator which periodically with 50 duty circle reverses a circuit of the reference current Im The simplified diagram of the Commutator is shown in Fig 4 2 In the no input signal state the output voltage of the Instrumentation Amplifier IA is equal to E 2 where Em 4 096 V Fig 4 3 Instrumentation Amplifier Fig 4 2 The simplified diagram of AC resistance measuring eel 4 2 REV 1 00 2003 RMT Ltd DX4165 Fig 4 3 Output signals of Instrumentation Amplifier at AC resistance measuring During AC resistance measuring the output voltage of the IA is sampled and measured by 12 bit ADC every time before Im current reversing The sampling points are marked as tim Fig 4 3 The voltage drops on TE module when positive current Up and negative current Un are used for a TE module resistance R calculation under the following formula n gt Up Un R __ 4 1 Z Te r 8 where Up voltage drop on TE cooler at positive testing current Ln Un voltage drop on TE cooler at negative testing curren
22. od which allows to avoid labour consuming thermophysical measurements This approach is based on the Harman method The Figure of Merit is the most important performance parameter of a TE cooler It is defined as Z 3 1 where a TE material Seebeck coefficient k thermal conductance of TE pellets material R Ohmic resistance of TE module Principle of Figure of Merit Measuring Sc DX4165 RMT Ltd From this time on we deal with the stationary mode values only see Ch 2 The base equations that describe a one stage TE module power balance 1 DS offo IR k AT o Ta To 2 N D B nit T R k AT bzw where To cold surface temperature T hot surface temperature AT T To T ambient temperature I current passing through TE module N TE pellets number ao environment cold side heat transfer term a environment hot side heat transfer term k effective pellets thermal conductance ee 3 2 REV 1 00 2003 RMT Ltd DX4165 The term Ki describes thermal conductance normalized to one pellet between the cold and hot surfaces k k 1 bth 3 3 where bc Beond Brad 3 4 The Bong and B aa are corrections for inter pellets thermal conductance values through air thermal Beond Kair f i 3 4a x B Here the pellets filling term is Ns B S where s a pellet cross section S the cold side area A zu Bra Y oO a 1 3 4b
23. ral dependence of the Seebeck voltage and the approach for obtaining the stationary voltage values is the same The measuring procedure is carried out both for two electric supply polarities The data collection duration and time step can be varied The measuring chart window is presented in Fig 2 1 Principles of time constant Measuring 2 3 DX4165 RMT Ltd gt E PR a bo be gt x O G D a Ka 0 0 000 76 1 60 2 44 3 28 4 08 4 92 5 76 6 60 7 44 5 28 9 08 9 92 time sec Fig 2 1 The example of the dynamic field the telemetry of the Seebeck voltage temporal behavior and corresponding interpolation curves via two polarities The obtained experimental data is then fitted by the following function U Ust 1 e 2 5 The exponential regression is based on the method of least squares As its outcome the procedure provides the time constant t and the stationary Seebeck voltage Ustoa 2 4 REV 1 00 2003 RMT Ltd DX4165 3 Principle of Figure of Merit Measuring 3 1 Theory of Operation Single stage TEC Among three parameters R Z AT max measured by DX4165 Meter only AC resistance R is measured directly The R measurement method is described in the Part AC Resistance Measurement of Chapter 4 The determination of the Figure of Merit Z and the maximum temperature difference AT of a thermolelctric TE module implements an indirect meth
24. rit and Atmax for Single stage TEC 3 3 Theory of Operation TEC mounted on the heat sink 3 4 Theory of Operation Z measuring of Two stage TEC 3 5 Material Z and Measured Z 4 Technics 4 1 DX4065 Meter Arrangement 4 2 AC Resistance Measurement 4 3 U and Ua Measurement 5 Working with Z Meter 5 1 Hardware Installation 5 2 DX4065 USB Drivers Installation 5 3 System Requirements 5 4 Program Installation 5 5 Hardware Preparation 5 6 Measurement of Parameters of TE coolers 5 7 The Main Program Window 5 7 1 Title 5 7 2 Menu bar 5 7 3 Reference Bar Contents DX4165 CO GO Co P P D DY ra N Fa O WOK Fi F i CA m oo o1 Oo 01 Oo OO OO Oo 01 OO OO OO A A A HL WO bot bt bt to tod ka ka ka Dr OO OO D ta ta BRN ta ta BD P D Hi A DX4165 Contents N 5 7 4 Functional Fields 5 8 Single stage TEC Z metering 5 8 1 Reference 8 2 Cooler type 5 8 3 Corrections Field 5 8 4 Measurement Notes 5 9 Z metering of a Single stage TEC on Heat Sink 5 10 Z metering of Two stage TEC 5 11 History 5 12 Database Update Maintenance Standard Kit Specifications RMT Ltd REV 1 00 2003 RMT Ltd DX4165 1 Introduction The DX4165 Z Meter provides precise measurement of Thermoelectric modules parameters maximum 10 identical modules at a time e AC Resistance R e Figure of Merit Z e Maximum Temperature Difference A
25. story Options Help Rescan Device allows Rescan Device repeating search of the device It is applied if the programs first attempt to Exit find the device failed I I TEC Base Editor allows editing the TE modules data banks see Database Update TEC Base Editor eee 5 1 2 REV 1 00 2003 RMT Ltd DX4165 e History Show displays or hide the le History Options Help History window see Fig 5 6 po Show New creates a new history ibi Ven Load downlods the history from JE Lee Cay Jaye a history file Print allows printing the history Print Add to history allows inputting Add to History the results manually R Ota Tirar pe a Tix fen E un 2 Zanon en e onst sec tonst sec Teonst sec 1MC06 046 05 1 125 6250 6380 6320 235 243 239 0 62 0 62 nei 2 124 6610 6700 6660 2 56 2 62 259 0 62 0 62 ve 3 134 oa 6180 6140 2 26 231 2 28 0 62 0 62 ve 4 152 om 5400 5350 184 1 39 187 0 62 0 62 062 5 123 6510 6620 6560 250 257 254 062 062 O62 6 125 6410 6490 6450 2 44 2 49 247 0 62 0 62 062 7 123 6230 6250 6240 2 34 2 35 234 0 62 0 62 nei 3 123 6650 6700 6680 2 59 2 62 261 0 62 0 62 062 9 124 6300 6390 6350 238 2 43 241 0 62 0 62 0 62 10 127 6280 6430 63 60 237 2 46 241 0 62 0 6
26. suring procedure is completed you can see the obtained corrections and results in the corresponding fields With all TEC parameters available all the corrections are taken into account by default The corrections are specified in Table 5 1 You are able to switch this or that correction on off with the help of corresponding radio button pairs on the Corrections field The Results window fits the changes automatically Table 5 1 Corrections for the One stage option calculated by 3 9a c for the Two stage option calculated by 3 22 3 25 excluding the Joule heating correction H em JL e Correction factor showing Joule heating sole hain ries dissipation ratio Inter pellets Correction factor to pellet thermoconductivity 2 p b due to additional heat flux from the warm side to input the cold one through the medium 3 tesche b Correction factor because of non zero ead ng wires Dr resistance of TE module wires eee 5 22 REV 1 00 2003 RMT Ltd DX4165 By default the Results field data are calculated with all the corrections switched ON in the Corrections field These corrections are equivalent to a certain coefficient a The latter is described in formula 3 28 The Coefficient Mode Field allows a User to apply either the coefficient calculated within all the ON corrections Default Mode or to offer one s own coefficient Manul Mode or to refuse any corrections and therefore se
27. t I In testing current Ay voltage gain of Instrumentation Amplifier Technics 4 3 DX4165 RMT Ltd The typical values of parameters in formula 4 1 are as follows Imn 2 mA Ay 5 or 50 n 50 4 3 U and U Measurement At measurement of U and Uy parameters the small current J is applied to a module periodically with 50 duty circle Two successive measuring sessions are necessary to obtain the U and U values at different testing current polarities Testing current Ir fi cee NL ee E eer E TEC total and Seebeck voltages Fig 4 3 Test current and voltages schematic temporal behaviour emeng 4 4 REV 1 00 2003 RMT Ltd DX4165 4 4 Voltage Values for the Harman Method Eq 3 9 contains both U and Ua These are the voltage values referred to the time tat which the process becomes steady Thus the Seebeck voltage in Eq 3 9 is equal to the stationary value Ust obtained by the interpolation procedure see Eq 2 5 The Ohmic voltage drop U is also calculated with reference to the time t It should be done for the reason the TEC resistance R undergoes a change due toa slight evolution of the TEC average temperature At the current I 0 01T it may have about 1 1 5 growth So the value U is resulted from the following averaging over the last 10 time points Up L gt wa U t 4 2 10 i gt N 10 Important Make sure the measured TEC has reached
28. t the coefficient equal one 5 8 4 Measurement Notes Important The temperature of a TE cooler changes slightly owing to a hands touching Also the measuring procedure induces slight cooler temperature increasing So maintain a pause of about this test 3 time constants before the next one It is 30 seconds on average This time is approximately enough to stabilize the TE cooler temperature see Chapter 2 Working with Z Meter 5 23 DX4165 RMT Ltd 5 9 Z metering of a Single stage TEC on the Heat Sink All the information presented above for Option 1 remains true except for the Heat Sink Parameters Field With the help of these parameters the corrections are calculated allowing for Formula 3 9a c and 8 15 5 10 Z metering of a Two stage TEC All the information presented above for Option 1 remains true except the following 1 A default Cooler type does not allow to estimate DTmax because for this purpose the cascading coefficient value is necessary 3 The Corrections field is the same but the corrections values are calculated differently for this case see formulae 3 22 3 25 2 For a two stage TEC ratio 2 4 is not applicable and the time constant can be only roughly estimated by the temporal dependence of the Seebeck voltage ee 5 24 REV 1 00 2003 RMT Ltd DX4165 5 12 Database Update If the parameters of a TE cooler you are going to deal with are not introduced in the
29. the steady state To assess it the telemetry capability is available Technics 4 5 DX4165 4 6 RMT Ltd REV 1 00 2003 RMT Ltd DX4165 5 Working with DX4165 Z Meter 5 1 Hardware Installation The DX4165 kit includes all that is necessary for plugging the device into the IBM personal computer PC Plugging in cable Power supply cable 8 USB drivers WIN 9x 2000 XP DX4165 software For plugging the DX4165 into PC the USB cable should be connected to PC Working with Z Meter 5 1 DX4165 RMT Ltd 5 2 DX4165 USB drivers installation 1 Plug the DX4165 Meter into your PC using the data cable supplied within the kit The following messages are to pop up Found New Hardware Wizard Welcome to the Found New Hardware Wizard This wizard helps you install a device driver for a hardware device Found New Hardware Wizard Install Hardware Device Drivers Fata A device driver is a software program that enables a hardware device to work with scl an operating system This wizard will complete the installation for this device 2 Meter Model DX4165 Cancel A device driver is a software program that makes a hardware device work Windows needs driver files for your new device To locate driver files and complete the installation click Next What do you want the wizard to do Search for a suitable driver for my device recommended Display a l
30. tial moment s Principles of time constant Measuring 2 4 DX4165 RMT Ltd conditions and is described by a multi exponential interference This phase fades out rather quickly and in case TEC pellets thermal conductance is high enough the temporal behavior can be characterized by the only exponent i e M pin lt lt mM 2 2 min for all possible indices n The theory yields the following expression for the time T l Mmin CCL q La 2 3 Gjt cl wen where C C TEC cold side and hot heat capacities a the thermoelectric TE material Seebeck constant K the TE material thermal conductivity N the TEC pellets number L the pellets length D their cross section J the electric current density D 2 2 REV 1 00 2003 RMT Ltd DX4165 As 2 3 shows t calculation is stumbling because in practice the values involved in it are never known to the proper accuracy extent The DX4165 allows to measure the time constant of single stage TEC s and to estimate that of more stage ones 2 2 Interpolation Results The procedure of handling the time constant measurement data is as follows The temporal behavior of a single stage TEC temperature difference is measured via the Seebeck voltage that is a corresponding proportional value U AT 2 4 For a two or more stage TEC this simple ratio is not applicable However the time constant can be estimated by the tempo
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