KD-5100 User Manual
Contents
1. FR The full range sometimes referred to as Full Scale of the system is defined as the total measurement distance For example a system with a 10 mil 0 25 mm range would have a full range of 20 mils 0 5 mm All percentage measurements are percent of the full range Coil Diameter This refers to the diameter of the sensing coil itself Eddy current systems performance at different ranges can most often be estimated generally i e normalized when considered as a percentage of the coil diameter This allows the results to be applied broadly The graphs following are based on this normalization Full Range as a of Coil Diameter in the graphs means that for a coil diameter of 0 140 3 55 mm the number of 50 the full range would be about 0 070 35 mils or 1 77 mm 40 885 mm which is equivalent to of the coil diameter Non Linearity Non linearity is computed as the maximum error from a best fit least squares line and divided by the full range A system with a non linearity of 0 2 FR and a 10 mil 0 25 mm range 20 mil 0 5 mm Full Range would have a maximum deviation of 0 2 x20 mil 0 04mils 0 2 x0 5 mm 0 001 mm www kamansensors com 27 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring Estimated Non Linearity of KD5100 6 00 5 00 J 4 00 3 00 2 00 1 00 0 00 0 10 20 30 40 50 60 70 80 90 100 Bes2. This At small ranges the output change is diminishing faster than the range is decreasing resulting in a net loss of sensitivity as a percentage of the measuring range www kamansensors com 30 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring Specific Example 15N Sensors The estimates below are fora 15N sensor The estimates are based on the coil diameter of 143 mils 3 63 mm The two tables contain the same data just in different units Note there is an entry for a 2 mil range 1 mil 50 micron 25 micron considerable amount of experience with this system and was not calculated This entry is based on a KD 5100 15N Sensor English Units Coil Offset Range Null Range NL NL mil Sensor Sensor Relative FR Res Null Res Dia mil mil mil 4 WFR IC TC Sens mil p p mil p p mil FERI C m er 1kHz 1kHz 1 6 2 7 1 0 10 0 002 0 05 0 001 0 10 0 001 0 0003 7 5 10 10 5 0 10 0 010 0 02 0 002 0 20 0 003 0 0008 14 5 20 15 10 0 15 0 030 0 02 0 004 0 40 0 003 0 0008 21 5 30 20 15 0 17 0 052 0 02 0 006 0 60 0 003 0 0008 28 10 40 30 20 0 25 0 100 0 03 0 010 0 80 0 003 0 0008 35 10 50 35 25 0 35 0 175 0 03 0 013 1 00 0 003 0 0008 49 10 70 45 35 0 50 0 350 0 03 0 021 0 60 0 0
3. electrically matching the sensors By using electrically matched sensors on opposing legs of the same bridge temperature effects common to the sensors and cabling of a differential sensor pair tend to be cancelled This is true for the mechanical aspects of the sensor target system also Assuming the thermal characteristics of each sensor track together slight changes in sensor length due to temperature tend to be cancelled 3 0 OPTIMUM PERFORMANCE To optimize the performance of a KD 5100 system a high d to s ratio is desired d is the sensor coil diameter and s includes the null gap the positive measuring range and 2 of the coil depth Figure 2 gt t lt TARGET HICKNE SENSOR eee ee COIL DIFFERENTIALA DIAMETER p TARGET MOTION TARGET za S NULL POSITIVE MEASURING RANGE D Figure 2 Sensor and Target Geometry www kamansensors com 6 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring The 15N sensor used over the specified 0 009 measuring range provides a d s ratio of 3 08 The ratio for the 20N is 10 68 Therefore if mounting space and target size permit the 20N offers better performance over the specified measuring range For either sensor model performance can be improved by decreasing the one variable the measuring range Significant reduction can provide a d s ratio up to 35 This effectively lowers the noise floor and improves resolution linear
4. step be accomplished using a fixture to hold the sensor and to control target movement However carefully hand holding and moving the sensor or the target will be sufficient for this check See Figure 11 for power and output connections at J5 The output for sensor S3 and S1 axis 1 is at pin 4 Slowly move the target through the sensor s measuring range to check for a full range of output for S3 0 V to 10 V Next Check S1 for 0 V to 10 V Note This will not be a linear output and you may get an output with the sensor as much as 15 or 20 mils away from its target That is OK since this check is only to confirm that the system is working Repeat the above test for sensor S4 10 V and S2 10 V Axis 2 output is pin 6 If the output does not change during this test Verify correct input voltage 14 5 to 16 V and 14 5 to 16 V Verify correct wiring to connector J5 reference Figure 11 Verify sensor connection and output connection to the correct channel for the sensor being checked S3 amp S1 axis 1 pin 4 S4 amp S2 axis 2 pin 6 Still no change contact Kaman Precision Products www kamansensors com 16 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 11 0 SENSOR INSTALLATION GUIDELINES AND PROCEDURE 11 1 Guidelines The sensors should be positioned at the null gap using the Electrical Nulling Procedure This installation procedure is the preferred method Tho
5. 0139 83 35 300 185 150 3 00 9 000 0 05 0 150 0 20 0 075 0 0250 96 35 350 210 175 5 50 19 250 0 06 0 210 0 15 0 117 0 0389 KD 5100 20N Sensor Metric Units Coil Offset Range Null Range NL NL um Sensor Sensor Relative ER Res Null Res Dia mm mm mm GER TC TC Sens um p p um p p mm FERIC wm C 1kHz 1kHz 3 0 254 0 254 0 381 0 127 0 10 0 25 0 02 0 05 0 10 0 127 0 0423 6 0 254 0 508 0 508 0 254 0 10 0 51 0 02 0 10 0 20 0 127 0 0423 8 0 254 0 762 0 635 0 381 0 10 0 76 0 02 0 15 0 30 0 127 0 0423 11 0 508 1 016 1 016 0 508 0 15 1 52 0 02 0 20 0 35 0 145 0 0484 14 0 508 1 270 1 143 0 635 0 15 1 91 0 02 0 25 0 40 0 159 0 0529 19 0 762 1 778 1 651 0 889 0 20 3 56 0 02 0 36 0 45 0 198 0 0659 22 0 762 2 032 1 778 1 016 0 20 4 06 0 02 0 41 0 60 0 169 0 0564 28 0 762 2 540 2 032 1 270 0 25 6 35 0 03 0 64 0 65 0 195 0 0651 41 0 889 3 810 2 794 1 905 0 50 19 05 0 03 1 14 1 00 0 191 0 0635 55 0 889 5 080 3 429 2 540 1 00 50 80 0 03 1 52 0 60 0 423 0 1411 69 0 889 6 350 4 064 3 175 1 50 95 25 0 04 Dud 0 30 1 058 0 3528 83 0 889 7 620 4 699 3 810 3 00 228 60 0 05 3 81 0 20 1 905 0 6350 96 0 889 8 890 5 334 4 4
6. 06 0 0019 56 10 80 50 40 1 00 0 800 0 03 0 024 0 50 0 008 0 0027 63 10 90 55 45 1 20 1 080 0 04 0 032 0 30 0 015 0 0050 70 10 100 60 50 1 60 1 600 0 04 0 040 0 30 0 017 0 0056 71 10 110 65 55 2 20 2 420 0 04 0 044 0 20 0 028 0 0092 84 10 120 70 60 3 00 3 600 0 05 0 060 0 20 0 030 0 0100 91 10 130 WS 65 4 20 5 460 0 05 0 065 0 20 0 033 0 0108 KD 5100 15N Sensor Metric Units Coil Offset Range Null Range NL NL um Sensor Sensor Relative FR Res Null Res Dia mm mm mm FR TC TC Sens um p p um p p mm FRC wm 1kHz 1kHz 1 0 152 0 051 0 178 0 025 0 10 0 05 0 05 0 03 0 10 0 025 0 0085 7 0 127 0 254 0 254 0 127 0 10 0 25 0 02 0 05 0 20 0 064 0 0212 14 0 127 0 508 0 381 0 254 0 15 0 76 0 02 0 10 0 40 0 064 0 0212 21 0 127 0 762 0 508 0 381 0 17 1 33 0 02 0 15 0 60 0 064 0 0212 28 0 254 1 016 0 762 0 508 0 25 2 54 0 03 0 25 0 80 0 064 0 0212 35 0 254 1 270 0 889 0 635 0 35 4 45 0 03 0 32 1 00 0 064 0 0212 49 0 254 1 778 1 143 0 889 0 50 8 89 0 03 0 53 0 60 0 148 0 0494 56 0 254 2 032 1 270 1 016 1 00 20 32 0 03 0 61 0 50 0 203 0 0677 63 0 254 2 286 1 397 1 143 1 20 27 43 0 04 0 80 0 30 0 381 0 1270 70 0 254 2 540 1 524 1 270 1 60 40 64 0 04 1 02 0 30 0 423 0 1411 77 0 254 2 794 1 651 1 397 2 20 61 47 0 04 1 12 0 20 0
7. 2 3 1 Install the sensors in the application fixture or calibration fixture and accurately establish the null position for the target see paragraph 11 3 WARNING Avoid eye contact with the silicone heat sink compound as it will cause temporary irritation 12 3 2 Remove the four screws securing the cover plate and remove it Silicone heat sink compound has been liberally spread between the hybrid case and the cover plate 12 3 3 Install the calibration cover plate power up the system and allow a 20 minute warm up period Monitor system output to verify stability NOTE Output at null should be ideally 0 000 V In practice this is very difficult to achieve since it requires positioning the target to within micro inches Thermal expansion caused by simply placing a hand on the calibration fixture can cause more movement than a micro inch Get as close to 0 000 V as possible not to exceed 10 mV 12 3 4 To adjust for 0 000 V e Monitor the output of axis 1 e Using the adjusting tool adjust the zero control for axis 1 Figure 14 for 0 000 V output AXIS 1 GAIN ae 1 50 EE Figure 14 Zero amp Gain Control Location Case Dimensions www kamansensors com 21 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 12 3 5 Move the target through a known displacement to its maximum range and adjust the axis 1 gain control Figure 14 for the desired output 12 3 6 Return the target to the nu
8. 3 625K 23 615K 1 00000 Analysis Results of Magnitude and Phase vs Frequency Frequency Hz Magnitude dB Relative Phase Shift Magnitude dB degrees 10 4 03 dB 0 00 0 00 100 4 03 dB 0 00 0 36 1000 4 03 dB 0 00 3 50 2000 4 03 dB 0 00 7 01 5000 4 02 dB 0 01 18 72 10000 3 74 dB 0 29 38 8 20000 2 17 dB 1 86 78 50 23600 0 94 dB 3 09 91 71 Summary of Gain and Phase Characteristics of KD 5100 Output Filter www kamansensors com 36 PART NO 860029 001 Last Revised 01 06 15
9. 33 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring Method of Computing Performance These results are based mainly on simulations First the sensor inductance and resistance was computed using a modeling program Then the effect of 2 meters of cable was factored in taking in consideration the transmission line effects of the cable After that the resultant inductance and resistance was put in a model to simulate the circuit bridge network The performance in each case was optimized to provide temperature coefficient as close to O2 FR as possible while adjusting the parameters for optimal linearity and reasonably good output The resulting data was then fit to exponential curves to provide a continuous function of non linearity and temperature coefficient vs coil diameter and the fit was very good Finally the results were then adjusted slightly based on data from actual systems and engineering judgment This means the system can be adjusted for better temperature coefficient if linearity and resolution are not a concern Better resolution can be obtained at the expense of temperature coefficient The tradeoffs were made to provide the best overall accuracy What good is excellent resolution if the temperature coefficient causes the output to drift out of range In general the results are reasonably accurate from about 10 50 of the coil diameter Ranges of less than 10 will have additional errors not account
10. 45 5 50 488 95 0 06 5 33 0 15 2 963 0 9878 www kamansensors com 32 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring Application Variables and Caveats The following application variables will also affect performance The effects listed are not considered in the results of the tables above and must be considered separately Sensor Loading Sensor loading by conductive materials that are incidentally in view of the sensors can affect the results significantly and must be considered on a case by case basis The discussions in this appendix assume that incidental materials do not load the sensor Cosine Error This is error that occurs when the target movement is from tilting as in a fast steering mirror assembly and can become significant at larger measuring ranges Cross Axis Sensitivity Errors This error occurs in 2 axis measurements of tip and tilt common in fast steering mirrors and can become significant at larger measuring ranges Setup Error The system can become very sensitive to the null gap position when setup for very small ranges Changes in the null gap will affect both the sensitivity and temperature coefficient Usually only significant problem on ranges of lt 10 mils lt 0 25 mm Target Effects Eddy current sensors are significantly affected by the target material resistivity and permeability Aluminum targets are considered in this
11. 60029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring APPENDIX A Total System Specifications sensor cable and electronics PERFORMANCE typical for stated measurement conditions Null Gap KD 5100 15N KD 5100 20N Measuring Range KD 5100 15N KD 5100 20N Sensitivity or scale factor Non Linearity KD 5100 15N KD 5100 20N Long Term Stability Stabilized at 70 F 21 C Thermal Sensitivity at Null 20 F to 165 F KD 5100 15N KD 5100 20N Frequency Response Equivalent RMS Input Noise DC to 5 KHz Effective Resolution ELECTRICAL Input Voltage Power Consumption system Power Dissipation 15N sensors 20N sensors Output Characteristics TEMPERATURE Electronics Sensors 15N 20N 20N cryogenic WEIGHT Electronics Performance is Typical for an aluminum target Bandwidth limited to 22 KHz 5 www kamansensors com English inches Metric mm 0 015 0 0001 0 381 0 003 0 020 0 0001 0 508 0 003 0 009 0 2286 0 009 0 2286 1V 0 00142 40mV 0 00142 0 5x 10 2 5x 107 2x10 1 x 20 5 x 10 month 1 27 x 10 month lt 5 x 10 F lt 2 3 x 104 C lt 5 x 10 F lt 2 3 x 10 C DC to 5 KHz 4x 10 VHZ max 1x 107 V Hz max Equivalent RMS Input noise x V bandwidth Hz 15 VDC 70mA Typical lt 2 Watts lt 10 microwatts per Sensor lt 50 microwatts per Sensor lt 5 ohms 5mA 4 F to 140 F 20 C to 60 C 62 F to 220
12. 699 0 2328 84 0 254 3 048 1 778 1 524 3 00 91 44 0 05 1 52 0 20 0 762 0 2540 91 0 254 3 302 1 905 1 651 4 20 138 68 0 05 1 65 0 20 0 826 0 2752 www kamansensors com 31 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring Specific Example 20N Sensors The estimates below are for a 20N sensor The estimates are based on the coil diameter of 363 mils 9 22 mm The two tables contain the same data just in different units KD 5100 20N Sensor English Units Coil Offset Range Null Range NL NL mil Sensor Sensor Relative FR Res Null Res Dia mil mil mil WFR TC TC Sens mil p p mil p p mil FRC ml 1kHz 1kHz 3 10 10 15 5 0 10 0 010 0 02 0 002 0 10 0 005 0 0017 6 10 20 20 10 0 10 0 020 0 02 0 004 0 20 0 005 0 0017 8 10 30 25 15 0 10 0 030 0 02 0 006 0 30 0 005 0 0017 11 20 40 40 20 0 15 0 060 0 02 0 008 0 35 0 006 0 0019 14 20 50 45 25 0 15 0 075 0 02 0 010 0 40 0 006 0 0021 19 30 70 65 35 0 20 0 140 0 02 0 014 0 45 0 008 0 0026 22 30 80 70 40 0 20 0 160 0 02 0 016 0 60 0 007 0 0022 28 30 100 80 50 0 25 0 250 0 03 0 025 0 65 0 008 0 0026 41 35 150 110 75 0 50 0 750 0 03 0 045 1 00 0 008 0 0025 55 35 200 135 100 1 00 2 000 0 03 0 060 0 60 0 017 0 0056 69 35 250 160 125 1 50 3 750 0 04 0 088 0 30 0 042 0
13. D 5100 Aluminum is preferred as the most practical target material Aluminum targets can be mounted on materials with more stable temperature characteristics such as Invar or other substrates as long as target thickness guidelines are observed Figure 5 INVAR ALUMINUM TAB TARGET e MOTION Figure 5 Aluminum Targets on Invar These systems are set up to work with other nonmagnetic conductive targets on a special order basis If you purchased a system for use with a target material other than aluminum it has been calibrated with selected component values at the factory using that target material An arbitrary change in target material may at a minimum require calibration or not work at all www kamansensors com 8 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 5 2 Thickness The RF field developed by the sensor is at a maximum on the target surface There is penetration below the surface and the extent of penetration is a function of target resistivity and permeability The RF field will penetrate aluminum to a depth of 0 022 a little more than three skin depths at one skin depth the field density is only 36 of surface density and at two skin depths it is 13 To avoid variations caused by temperature changes of the target the minimum thickness should be at least three skin depths The depth of penetration depends on the actual target material used In cases where the sens
14. F 55 C to 105 C 62 F to 220 0F 55 C to 105 C 4 Kelvin 4 0z 113gr 26 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring APPENDIX B Measuring Range and Performance Tradeoffs This Appendix presents the performance tradeoffs associated with range on the KD 5100 differential measurement system In particular the performance parameters that matter are non linearity temperature coefficient and relative sensitivity which affects resolution and electronics temperature coefficient This Appendix gives generalized results based on coil diameter and then applies the results to the two most popular sensors used with the KD 5100 the 15N and 20N Note This Appendix illustrates typical performance and is not in itself a specification of performance Actual specifications vary depending on a number of application variables and optimizations based on customer input These illustrations do not account for those variables Actual performance may vary from these estimates Refer to the Kaman Specification sheet on the KD 5100 for specific details on actual performance Definitions The following definitions are important when discussing performance Offset The closest distance from the sensor face to the target that is still within the measuring range Null Gap The distance from the sensor face to the target when the target is equidistant between the sensors Reference figure 15 Full Range
15. KAMAN Precision Products Measuring KD 5100 Differential Measuring System User s Manual TABLE OF CONTENTS Copyright 2015 Kaman Precision Products PART NO 860029 001 A Division of Kaman Aerospace Corporation Last Revised 01 06 15 217 Smith Street Middletown CT 06457 www kamansensors com KAMAN Precision Products Measuring 1 0 W iere en ue D A 2 0 THEORY OF OPERATION ee 5 3 0 OPTIMUM PERFORMANCE iiscirccscciceesdecileusheaiceeSdeniteuSdenidenidentiensien enters nnen rennene 6 4 0 APPLICATION INFORMATION 7 5 0 TARGETS oaa a ee en EERI EIR 8 Dil Reegele E E 8 Dee Ke EN 9 ee a EE 9 6 0 SPECIAL HANDLING CAUTIONS siic5iceste hice sile tite e heehee ttn ee 9 SC SEENEN EE EE 9 6 2 Mounting ere 10 7 0 EES 11 7 1 Factors that degrade performance sees 11 7 2 Pivot point requirements eet eener 11 7 3 Sensor ue Ui inte Ee 13 8 0 CROSS AXIS SENSIT IVI Y nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnrrrrrrrrrrrrrrrnrnrnnrnrrnnennn 14 8 1 Cross axis sensitivity may occur under the following conditions ssse00000 14 8 2 Additional points of emphasis about cross axis sengitiviiy 14 9 0 PINOUT and CONNECTOR ASSIGNMENTS nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn 15 10 0 USER S ABBREVIATED FUNCTIONAL TEST 16 11 0 SENSOR INSTALLATION GUIDELINES AND PROCEDURE 17 TET le E EE 17 Nee E 17 12 0 CALUIBRATION ce eeeeeeeeesseeeeeeeseeessssesesesessss
16. appendix In general the KD 5100 is best used with non magnetic relative permeability 1 low resistivity targets The effect this has on the sensor is dependent on the operating frequency and coil diameter Cable Length The KD 5100 sensors are passive This means that the cable is an integral part of the sensor and affects measurement performance The data presented assumes a 2 meter cable length Actual results may vary with different cable lengths Long cables are especially bad for performance because they degrade the effective Q of the sensor and increase the inherent temperature coefficient of the sensor coil Long cables will also cause problems with thermal drift and variations in the output caused by cable movement Optimization In the data presented the circuit was optimized for each range This means that the component values in the circuit may be different for each specific measuring range The system will not get the performance shown simply by changing the range and recalibrating it would require factory optimization The system could also be optimize for a specific parameter ex temperature and achieve better performance in that category allowing the other performance parameters to be worse The data shown for a specific range is a compromise of all the performance parameters At each measurement range listed the linearity temperature coefficient and sensitivity listed are achievable simultaneously www kamansensors com
17. bricate one from 0 062 thick aluminum Dimensions and location of the holes are shown in Figure 13 www kamansensors com 19 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring SENSOR CONNECTORS GAIN GAIN CHANNEL A H TANNVHOD ZERO ZERO O POWER CABLE CONNECTOR Figure 13 Calibration Cover Dimensions see Figure 6 for additional cover plate dimensions 12 1 Equipment Required A dimensional standard A regulated 15 VDC power supply A voltmeter accurate to one millivolt or better An insulated adjusting tool tweaker Kaman P N 823977 T007 A calibration cover plate NOTE When performing a system calibration it is preferable to have the system installed in the application fixture at normal operating temperatures This eliminates any shift in system output caused by moving the system from a calibration fixture to the application fixture translation error 12 2 Calibration Procedure Overview Calibration involves the following steps Null the Target Monitor the output of axis 1 Adjust for 0 000 V output Move the target to full displacement Adjust for full output voltage Return the target to the null position and check for an output of 0OV 10mV Repeat for axis 2 The following information details these five steps www kamansensors com 20 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 12 3 Calibration Steps 1
18. dard Since it is difficult for users to duplicate our calibration conditions call us before attempting any adjustments of your KD 5100 On the other hand it is equally difficult for Kaman to duplicate your actual application conditions so special circumstances may dictate come calibration Again coordinate with a Kaman engineer first Maintainability The KD 5100 is designed so that scheduled maintenance and adjustments are not required The unit can be removed and replaced without special tools Environment The KD 5100 provides specified performance after exposure to all natural and or induced environments encountered during manufacture test transportation handling storage installation and removal operations www kamansensors com 4 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 2 0 THEORY OF OPERATION The KD 5100 Differential Measuring System uses advanced inductive measurement technology to detect the aligned or centered position of a conductive target Two matched sensors are positioned relative to the target so that as it moves away from one sensor it moves toward the other an equal amount The transducer operates on the principle of impedance variation caused by eddy currents induced in a conductive target located within range of each sensor The coil in the sensor is energized with an AC current causing a magnetic coupling between the sensor coil and the target The strength of this cou
19. e a common line between the centerline of a pair of sensors The axis of tilt must be a perpendicular bisector of a line between the centerlines of a sensor pair The pivot point must be positioned on the target so as not to introduce a translation error This error a function of angle is caused by slight changes in the effective null gap as the target moves about the pivot This results in non linearity The pivot point must not change or move with time www kamansensors com 11 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 004B total length 0 506 Figure 7 15N Sensor Dimensions 0 001 i Dann 01 BIA THREAD 4 40 UNC2B 3X ACTUAL SIZE BELLEVILLE SPRING WASHER d OPTIONAL I Figure 8 20N Sensor Dimensions www kamansensors com PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 7 3 Sensor mounting considerations The sensors must be securely clamped Sensor dimensions are shown in Figures 7 amp 8 The target must not strike the sensor face The system has a null gap and a specified full measuring range The difference between the null gap and measuring range is the offset distance for the sensors This offset is necessary both to optimize performance and to keep the target from contacting and possibly damaging the coils in the sensor face The sensor coil is mounted at the face of both types of sensor Fo
20. ed for such as thermal expansion of the sensor body Ranges less than 10 and greater than 50 will also have errors due to mismatch in the sensors and electronics A Note about Small Ranges There is a point of diminishing returns when the range is small relative to the coil diameter Ata range of about 20 of the coil diameter the amount of change in the measured variable becomes small rapidly This causes the inherent output of the system to be reduced such that as more gain is added in the electronics to compensate effective resolution does not increase In fact noise as a of the range starts to increase Significant errors can also occur from sensor body thermal expansion and component matching in the electronics The break even point is at a range of about 5 of the coil diameter This means that reducing the range will not improve effective performance and dynamic range will be reduced A range that is too small also makes it more difficult to set up the sensor within its measurement range Other Observations 1 Performance degrades rapidly when the range exceeds 50 of the coil diameter 2 There is a limit floor to the resolution and accuracy when operating over very small ranges lt 5 of the coil diameter 3 Optimum performance is obtained with a measuring range approximately 35 of the coil diameter This is where the best tradeoff between resolution non linearity and temperature coefficient will be achieved www
21. ent units is required Kaman Precision Products uses a laser interferometer as a primary dimensional standard for calibration Recalibration Recalibration to a sensitivity and or measuring range significantly different from the factory calibration may not be possible For example if you purchased a standard system calibrated 0 to 9 volts over a 9 mil measuring range 1V mil and attempted to recalibrate for 9 volts over a 3 mil measuring range 3V mil there may not be sufficient gain adjustment to do this These units are built with component values selected for each application Therefore changes in measuring range sensitivity or target material may not be possible and will require reconfiguration by Kaman Precision Products Thermal Equilibrium The mounting cover plate helps maintain thermal equilibrium inside the module and acts as a heat sink for the hybrid circuit The hybrid has two watts of power to it and needs the cover plate for heat sinking The calibration controls are located inside the unit and the cover plate must be removed to access them Removing the cover plate removes its heat sinking function Calibrating with the cover off and then reinstalling it will cause enough of a thermal gradient to throw the calibration off Kaman s solution is to use a cover plate with access holes for the calibration controls This plate is available as an accessory from Kaman You may either obtain a calibration cover plate from Kaman or fa
22. eseeseeeseeseeeeeeeseeeseeeeeeeeeeeees 19 12 1 let We Ml RegU ired EE 20 12 2 Calibration Procedure e E 20 12 3 Calibration Steps E 21 13 0 TROUBLESHOOTING oss soscsccs aac icssscasscnssdadscchsdnccaesscedscsedeceeceesce deeds 23 14 0 TERMINOLOGY E 24 15 0 CUSTOMER SERVICE INFORMATION ccc eeeesessssssesseseesesesseeeeeeeees 25 APPENDIX A Total System Specifications sensor cable and electronics 26 APPENDIX B Measuring Range and Performance Tradeoffs seeeeeeeeeeeees 27 APPENDIX C Output Filter Characteristics of the KD 5100 ssseeeeeeeeeeeees 35 www kamansensors com 2 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring ILLUSTRATIONS Figure 1 Block Diagram Differential Measuring System ssosnsneeneenenenenneeneseeeseeeene 5 Figure 2 Sensor and Target GeOMetry 2 ccccccccceseseeneenseeeeeeeeeeneeeeeeeeseneeeeeeeneneneneee 6 Figure 3 Differential Target Configurations cccccccsecssenssnsssennneenneeeeeeneeneneceeenenets 7 Figure 4 x y Mirror Alignment Confguraton 8 Figure 5 Aluminum Targets on Invar sssssseseennnnnenensnsseeeeerrrrererrrrrrrrrrrererrrrrrrrerreessereent 8 Figure 6 Mounting Cover Plate Dimensions sssssssssentennessesererrrrnrnnsstrrrrrnrnnneeeerenne 10 Figure 7 15N Sensor Dimensions xognien scent tniosesnsesosasnsenososnsesosatnsonesesnsonosarnsonesemnsebesesters 12 Figure 8 20N Sensor Dime
23. he pair S1 in the fixture and position it to within a few mils of the required null gap Connect the Power Signal line to J5 and apply power to the system Use the output from the system as a guide in the final positioning of this sensor electrical nulling Slowly move the second sensor toward or away from the target as necessary until the system output reads 0 VDC ideally 0 000 V This output means the sensor is positioned correctly 11 2 4 Repeat steps 11 2 1 through 11 2 3 for sensor S4 and S2 11 2 5 The system is now ready for use www kamansensors com 18 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 12 0 CALIBRATION KD 5100 systems are shipped from the factory pre calibrated for a user specified measuring range sensitivity and target material They do not normally require calibration or re calibration However some applications may require the availability of this option The calibration procedure is very simple However it requires an accurate dimensional standard and a stable environment Some considerations Dimensional Standard To calibrate a dimensional standard micrometer laser interferometer a weight to provide a known deflection etc is required This should be a standard known to be accurate and repeatable Whether measuring in mils microns micro radians etc a means of accurately positioning the target using the dimensional standard to the desired measurem
24. hes per month If the unit does not work this would most likely be discovered during the Abbreviated Function Test Section J Our experience in numerous applications over years of use is that these systems either work or don t and are not subject to quirky or drifty behavior If unable to calibrate the system in no more than two iterations the problem is most likely poor mechanical repeatability in the fixturing or actuating mechanisms 13 3 There is a way to check it out Do not make any adjustments to the calibration controls Record how much time the next step takes Perform 12 to 15 iterations of moving the target from null to full range and back to null Record the output at null each time If successive readings of the output at null constantly very with no clear trend drift in one direction or the other the problem is mechanical repeatability Now stabilize the target at null and record the output Leave the target at null for the same length of time it took to accomplish step two and monitor the output If the output remains constant this confirms the problem was mechanical repeatability If the output drifts the problem could be e drift in the fixturing e drift in the target positioning servos e drift in the KD 5100 If you can positively eliminate all other variables as the source of the problem contact Kaman Precision Products Remember if unable to calibrate the KD 5100 and it passed the Abbreviated Funct
25. ion Test it is the least likely source of the problem www kamansensors com 23 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 14 0 TERMINOLOGY Null Gap The null gap is the point at which a target is equidistant from each sensor of a differential pair The system output at null 0 V The actual gap is measured from the sensor face to the corresponding target face and includes a required offset null gap offset plus maximum measuring range Offset The offset is the minimum distance between the sensor face and the target Offset is necessary to prevent the target from striking the sensor face and to optimize performance offset null gap minus max range Measuring Range The measuring range is the full range of target motion over which the various specifications such as resolution linearity and sensitivity can be met The differential sensor arrangement yields a bipolar output and measuring range is expressed as a and value either side of the null position measuring range null gap minus the offset A B NULL GAP A B 0 020 FOR 20N SENSOR ell OFFSET Le MEASURING RANGE Figure 15 Null Gap Offset Measuring Range Sensitivity Sensitivity is the output voltage per unit of displacement Usually expressed as millivolts per mil 0 001 or per millimeter Linearity Linearity is the maximum deviation of any point of a calibrated system s output from a best fit s
26. ity and thermal stability The temperature of the mounting surface and the environment for the electronics should not exceed the specified 20 C to 60 C 4 F to 140 F For optimum performance stabilize the temperature for the mounting surface electronics at a constant temperature within this range preferably 25 C 4 0 APPLICATION INFORMATION For differential measurement applications the two electronically matched sensors are positioned on opposite sides or ends of the target Figure 3 The sensor to target relationship is such that as the target moves away from one sensor it moves toward the other an equal amount ca 1 Figure 3 Differential Target Configurations A standard system comes with two measurement axes four sensors two per axis and can therefore be fixtured a number of ways to provide precise x y alignment Figure 4 illustrates target configuration for x y alignment of an image stabilization mirror for an electro optical application DO NOT MAKE ANY MODIFICATIONS TO CABLE LENGTH SENSOR OR CALIBRATED TARGET MATERIALS WITHOUT CONSULTATING A KAMAN APPLICATION ENGINEER www kamansensors com 7 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring Y AXIS MIRROR BACK ALUMINUM TAB X AXIS PIVOT Figure 4 x y Mirror Alignment Configuration 5 0 TARGETS 5 1 Material Iron nickel and many of their alloys magnetic targets are not acceptable for use with the K
27. kamansensors com 34 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring APPENDIX C Output Filter Characteristics of the KD 5100 Applications utilizing the KD 5100 as the displacement feedback in closed loop systems generally require information about the gain and phase delay vs frequency The output filter largely controls these KD 5100 characteristics in most applications Output Filter Schematic The output filter is a standard 2 pole Butterworth configuration It is set for a cutoff frequency 3 dB of approximately 23 kHz C1 1000pF V 6 8k Output Filter Schematic Analysis Results The filter was analyzed using Micro Cap V The plot and table below show the magnitude dB and phase degrees output for the standard configuration in the KD 5100 The 3 dB point is at about 23 kHz There is a small gain of 1 59 about 4 dB in the circuit www kamansensors com 35 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring Phase Magnitude 0 04 20 00 KD5100 Output Filter Analysis 5100FIL2 CIR Temperature 27 Case 1 40 03 10 00 e DEE nis ainis a ie n rr 80 02 0 00 Ja Magnitude e Pe ge ae Seen ener ee Ee 160 01 20 00 oS FREQUENCY di rt Tn a ae 400 4K 40K 400K Left Right Delta Slope DB V 8 4 028 0 943 3 085 1 306e 04 PH V 8 0 038 91 748 91 709 3 884e 03 F 0 010K 2
28. ll position and check the output You most likely will not see 0 000 V output unless you have a very good dimensional standard and very stable fixturing located in a controlled environment When measuring at sub micro inch levels the world becomes rubber and the fixturing may have expanded or contracted and you won t see 0 000 V again 12 3 7 After returning the target to the null position output should be 0 000 V 10mV or less If the output at null exceeds this repeat the process Calibration should not take more than two iterations 12 3 8 Repeat the process for axis 2 monitoring the output at pin 6 12 3 9 The system is ready for use www kamansensors com 22 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 13 0 TROUBLESHOOTING What if the above calibration process doesn t work if there is not enough gain for the desired output or if a consistent 0 000 V 10 mV cannot be achieved 13 1 Insufficient Gain When recalibrating for a sensitivity measuring range or target different from factory calibration specifications there may be insufficient gain control Another cause for insufficient gain could be excessive loading of the sensors by conductive material other than the target within the field of the sensors The sensor s field is approximately three times its diameter 13 2 Cant Zero The KD 5100 is an extremely stable measuring system long term drift is less than 2 micro inc
29. nsions seis ccecccens sevscensceestexs teestensiees ters teesten beens ersten teenies 12 Figure 9 Sensor Coil Dimensions acces eoecceec ede deeceeacdencedecdceceeacdcacedacddecdeacdeauveecdeeeteaeeeed des 13 Figure 10 Sensor Cable COnme cui aiccoscsccscnsetoncsosoceandnsetoncdosedeandnesoncdoiedeadinietenddonetens 15 Figure 11 Power amp Output E GEET 15 ler a FS e S E E E E E 17 Figure 13 Calibration Cover DIM NSIONS 2ccc eececeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeteneeene 20 Figure 14 Zero amp Gain Control Location Case Dmensions 21 Figure 15 Null Gap Offset Measuring Range ssssssessssssssessessseseeeeeeeeeeenerererrereereeenne 24 www kamansensors com 3 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring KD 5100 SERIES DIFFERENTIAL MEASURING SYSTEMS SYSTEM SPECIFICATIONS Sensor Type Null Gap Offset Measuring Range Full Scale Output Scale Factor Target Material 1 0 INTRODUCTION This manual describes installation and use of the KD 5100 theory of operation ways to optimize performance special handling cautions functional tests and guidelines for fixturing and targets and calibration procedures Calibration Though there is a section on calibration these systems are shipped from the factory calibrated for a user specified target sensitivity and measuring range We calibrate these systems in a controlled environment using a precision laser as a primary dimensional stan
30. ors are opposing each other aluminum target thickness must be at least 0 050 to prevent sensor interaction Material Thickness in mils Silver and Copper 22 Gold and Aluminum 22 Beryllium 25 Magnesium Brass Bronze Lead 58 300 Series Stainless 110 Inconel 110 Recommended minimum target thickness in mils 5 3 Size The minimum target size is at least 2 times sensor diameter 6 0 SPECIAL HANDLING CAUTIONS 6 1 Sensors Due to design requirements the sensor coil is exposed The sensors are shipped with protective caps Keep them in place until installation of the sensors CAUTION ff any sharp object comes in contact with the coil face or edge and damages it in any way this could short a number of turns in the coil alter its impedance and render the sensor useless www kamansensors com 9 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 6 2 Mounting Surface The base plate of the electronics module has a smooth surface to enhance thermal conduction away from the electronics Mounting the base plate flush with another surface will enhance thermal dissipation assuming a mount surface with a temperature below 60 C Base plate dimensions and mounting hole spacing are shown in Figure 6 125 DIA THRU 82 C SINK TO 26 DIA 4 HOLES FOR ATTACHMENT OF COVER 140 DIA THRU 4 HOLES FOR MOUNT ING Figure 6 Mounting Cover Plate Dimensions Figure 6 Mounting Cover Pla
31. pling depends upon the gap between them and changes in gap cause an impedance variation in the coil In the KD 5100 the coils of a pair of sensors form the opposite legs of a balanced bridge circuit Figure 1 OSCILLATOR DEMODULATOR SYSTEM aB 15 Vde VOLTAGE COMMON REGULATOR 15 Vde TARGET SENSORS Figure 1 Block Diagram Differential Measuring System When the target is electrically centered between the two sensors at the nominal null gap for each the system output is zero As the target moves away from one sensor and toward another the coupling between each sensor and target is no longer equal causing an impedance imbalance between the sensors The bridge detects this imbalance and its output is amplified demodulated and presented as a linear analog signal directly proportional to the targets position This is a bipolar signal that provides both magnitude and direction of misalignment Only the differential output is available www kamansensors com 5 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring This differential configuration achieves its high resolution by eliminating the noise and drift any intervening summation and Log amplifiers normally add to the system Maximum performance depends upon advanced sensor technology Factors critical to the high resolution of the KD 5100 are tighter manufacturing control using significantly larger coils for a given range of operation and
32. r manifests itself as increased non linearity of the output at the extreme end points of target travel only This non linearity can change overall linearity from the specified 0 1 to about 0 3 8 2 Additional points of emphasis about cross axis sensitivity Again the error manifests itself only at the end points of target travel the last 20 when the target tilts fully in both x and y axes The degree of error is related to the angle between the sensor and target face As a general rule for angles 1 or less there is virtually no problem with cross axis sensitivity Sensor target angle is a function of the distance between the sensor and target pivot and the measuring range A sensor with a range of 10 mils mounted 10 mils from the pivot will experience 45 of tilt at the end points This is an extreme example but suffices to illustrate the point A sensor with a 10 mil range must be mounted approximately 550 mils 13 9 mm a little over inch from the pivot to achieve a 1 angle between sensor and target This phenomenon is related to basic physics and is stable repeatable small in magnitude and can therefore be characterized If necessary users can provide a computer correction scheme Cross axis sensitivity is not a problem for the majority of applications If you anticipate or experience the problem contact Kaman Precision Products for test data which specifies under which conditions and to what degree cross axis
33. r purposes of mechanical nulling measure distance from the sensor face For electrical nulling the most accurate method the null gap is referenced to the electrical centerline which is one half of the coil depth D Figure 9 If the face of the sensor and the target surface are not parallel if the sensor centerline is not perpendicular to the target more than 2 to 3 it will introduce error to the measurement 015 gt D Ks Ca Figure 9 Sensor Coil Dimensions www kamansensors com 13 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 8 0 CROSS AXIS SENSITIVITY Assuming you have stable and repeatable fixturing and have followed all of the rules for target mounting pivot points etc under certain conditions the system may exhibit signs of error we classify as cross axis sensitivity 8 1 Cross axis sensitivity may occur under the following conditions The target must be one with x and y axes of tilt moving about a central pivot point see Figure 4 When the target tilts full range in its x axis it should be able to tilt full range in its y axis without any change in the indicated output of the x axis or vice versa This may not be the case Cross axis tilt can increase the coupling between the sensor and target which causes a slight change in output though there is no change in the actual distance between the sensor and target This is a definition of error This erro
34. sensitivity exists www kamansensors com 14 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 9 0 PIN OUT and CONNECTOR ASSIGNMENTS Sensor cable connections Figure 10 AXIS CONNECTORS SENSORS 1 J3 J1 S3 S1 2 J4 J2 S4 S2 T 32 EI 1 Figure 10 Sensor Cable Connections Pin assignments for the Power Signal line connector J5 Figure 11 PIN FUNCTION 15 VDC 15 VDC Power Supply Common Signal Output Axis 1 Return Signal for Pin 4 Signal Output Axis 2 Return Signal for Pin 6 Not Used Not Used OONDARWN A Power Requirements Tolerance 15 VDC 1 0 0 5 VDC 15 VDC 0 5 1 0 VDC TT Cannon Connector MDM 9SL2P Figure 11 Power amp Output Connections www kamansensors com 15 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 10 0 USER S ABBREVIATED FUNCTIONAL TEST This is not a calibration or installation procedure This unit is factory calibrated and installation guidelines are in the next section This is simply a check to make sure the system is functioning upon receipt Perform this abbreviated functional test prior to installation of the electronics and sensors in the application fixture Attach the power supply cable to connector J5 and apply power to the system While monitoring the system output place an aluminum target within 0 015 15N sensor or 0 020 20N sensor of sensor S3 It is preferable this
35. sensors com 29 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring Relative Sensitivity The relative sensitivity is a way of comparing the expected resolution of the system The relative sensitivity is computed such that a system with a relative sensitivity of 1 would have resolution of 0 005 FR peak to peak when measured at a 1 kHz bandwidth with the sensors positioned at the extreme end of the measuring range The resolution at null is generally better by a factor of 3 A relative sensitivity of 0 5 would effectively double the noise in the system and the temperature coefficient in the electronics as a percent of the measuring range i e 1 is good 0 5 is not as good This also affects the temperature coefficient of the electronics in the same relative manner Ata relative sensitivity of 1 the electronics has a temperature coefficient of approximately 0 01 to 0 02 FR C typically Estimated Relative Sensitivity of KD5100 1 20 1 00 0 80 0 60 Relative Sensitivity 0 40 0 20 0 00 0 10 20 30 40 50 60 Full Range as of Coil Diameter 70 80 90 100 Relative Sensitivity is optimum around 35 of the measuring range for the following reasons At large ranges the output change remains constant while the range is increasing sensitivity number would obviously have a limit at 0 as the range increased to infinity
36. t Fit Non Linearity as of Full Range Full Range as of Coil Diameter Below is the same graph on an expanded scale Estimated Non Linearity of KD5100 0 90 0 80 0 70 0 60 0 50 0 40 0 30 0 20 0 10 0 00 0 10 20 30 40 50 Full Range as of Coil Diameter Best Fit Non Linearity as of Full Range www kamansensors com 28 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring Temperature Coefficient Temperature coefficient is calculated as the worst case shift over temperature Temperature coefficient is also presented as a percentage of Full Range A system with a full range of 20 mils 0 5 mm would have system with a temperature coefficient of 0 02 FR C or about 0 004 mils C 0 1um C Typically the temperature coefficient of a KD 5100 is the worst when at the extremes of the range and is excellent at the null position because the sensors are balanced This appendix refers only to the temperature coefficient of the sensors and does not include the electronics temperature coefficient which will be affected by the relative sensitivity Estimated Temperature Coefficient of KD5100 0 06 0 05 0 04 0 03 0 02 0 01 0 00 0 10 20 30 40 50 60 70 80 90 100 Temperature Coefficient FR degC Full Range as of Coil Diameter www kaman
37. te Dimensions www kamansensors com 10 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 7 0 FIXTURING The user provides fixturing for the KD 5100 electronics and sensors The following information establishes fixturing requirements for optimum system performance The quality of the measurement is both a function of Kaman s system and your Fixturing Both the sensor and target fixturing must be structurally sound and repeatable 7 1 Factors that degrade performance Unequal Loading This refers to an unequal amount of conductive material within the field of one sensor of a pair as opposed to another the sensor s field is approximately three times its diameter Unequal loading causes asymmetrical output from the sensor which induces non linearity in the system output Ideally no conductive material other than the target should be in the sensor s field Some loading may be acceptable if it is equal and the sensors are calibrated in place Even then sensor loading may cause non linearity If unable to calibrate loading is too great Unequal Displacement For targets using a pivot point mount examples Figures 3 amp 4 the system should see equal displacement i e the pivot point of the target is perfectly centered between the sensors If the pivot point is a fraction of a mil off it can introduce non linearity into the system 7 2 Pivot point requirements The pivot point must b
38. traight line Express in actual units e g micro inches www kamansensors com 24 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring Equivalent RMS Input Noise Equivalent RMS Input Noise is a figure of merit used to quantify the noise contributed by a system component It incorporates into a single value several factors that influence a noise specification such as signal to noise ratio noise floor and system bandwidth Given a measuring systems sensitivity scale factor and the level of white noise in the system Equivalent RMS Input Noise can be expressed using actual measurement units Effective Resolution Effective Resolution is an application dependent value determined by multiplying the Equivalent RMS Input Noise specification by the square root of the measurement bandwidth Example An application with a 100Hz bandwidth using a KD 5100 with an Equivalent RMS Input Noise level of 0 2nm VHz results in a system with an effective resolution of 0 2nm VHz x 100Hz or 2 nano meters 15 0 CUSTOMER SERVICE INFORMATION Should you have any questions regarding this product please contact a Kaman Precision Products applications engineer at 800 552 6267 You may also contact us through our web site at www kamansensors com or general email address measuring kaman com In the event of a product malfunction contact Kaman Precision Products for a return authorization www kamansensors com 25 PART NO 8
39. ugh both sensors may be positioned mechanically this can cause a cumulative error By electrically positioning the second sensor of a pair using system output any existing error is self canceling Install the sensors so that only the target interacts with the sensor s field This means no conductive material other than the target within a circle around the sensor that is three times the sensors diameter The sensor field radiates in all directions Figure 12 Excessive back loading can also be a problem CAUTION Be careful not to damage the sensor coil during this procedure SENSOR FIELD 3 TIMES SENSOR DIAMETER 3xd LSN Figure 12 Sensor Field 11 2 Procedure This procedure assumes the electronics are installed in the application fixture The sensor coil is mounted at the face of both sensors For purposes of mechanical nulling measure distance from the sensor face For electrical nulling the null gap is referenced to the electrical centerline which is one half of the coil depth 2D Figure 9 11 2 1 Verify the target is in the null position 11 2 2 Install the first sensor of a pair start with S3 in the application fixture Using a dimensional standard precisely locate the sensor at the null gap specified at time of order Secure the sensor and recheck its position www kamansensors com 17 PART NO 860029 001 Last Revised 01 06 15 KAMAN Precision Products Measuring 11 2 3 Now install the second sensor of t
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