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MODEL 4200 SERIES STRAIN GAUGES

| HIGH-TEMPERATURE THERMISTOR LINEARIZATION |

APPENDIX D.

HIGH-TEMPERATURE THERMISTOR

LINEARIZATION

Resistance to Temperature Equation for

US Sensor 103JL1A

EQUATION 9:

High-Temperature Resistance to Temperature

Where:

= Temperature in °C

LnR

= Natural Log of Thermistor Resistance.

= 1.127670 x 10

-3

= 2.344442 x 10

-4

= 8.476921 x 10

-8

= 1.175122 x 10

-11

Note:

Coefficients optimized for a curve

thermistor over the temperature

range of 0 °C to +250 °C.

TABLE 12:

Thermistor Resistance versus Temperature for Model 4200HT

Ohms

Temp Ohms Temp Ohms Temp Ohms Temp Ohms Temp Ohms Temp Ohms Temp Ohms Temp

32,650

7,402 32

2,157 64

763.5 96

316.6 128

148.4 160

76.5

192

42.8

224

31,029

7,098 33

2,083 65

741.2 97

308.7 129

145.1 161

75.0

193

42.1

225

29,498

6,808 34

2,011 66

719.6 98

301.0 130

142.0 162

73.6

194

41.4

226

28,052

6,531 35

1,942 67

698.7 99

293.5 131

138.9 163

72.2

195

40.7

227

26,685

6,267 36

1,876 68

678.6 100

286.3 132

135.9 164

70.8

196

40.0

228

25,392

6,015 37

1,813 69

659.1 101

279.2 133

133.0 165

69.5

197

39.3

229

24,170

5,775 38

1,752 70

640.3 102

272.4 134

130.1 166

68.2

198

38.7

230

23,013

5,545 39

1,693 71

622.2 103

265.8 135

127.3 167

66.9

199

38.0

231

21,918

5,326 40

1,637 72

604.6 104

259.3 136

124.6 168

65.7

200

37.4

232

20,882

5,117 41

1,582 73

587.6 105

253.1 137

122.0 169

64.4

201

36.8

233

19,901

4,917 42

1,530 74

571.2 106

247.0 138

119.4 170

63.3

202

36.2

234

18,971

4,725 43

1,480 75

555.3 107

241.1 139

116.9 171

62.1

203

35.6

235

18,090

4,543 44

1,432 76

539.9 108

235.3 140

114.5 172

61.0

204

35.1

236

17,255

4,368 45

1,385 77

525.0 109

229.7 141

112.1 173

59.9

205

34.5

237

16,463

4,201 46

1,340 78

510.6 110

224.3 142

109.8 174

58.8

206

33.9

238

15,712

4,041 47

1,297 79

496.7 111

219.0 143

107.5 175

57.7

207

33.4

239

14,999

3,888 48

1,255 80

483.2 112

213.9 144

105.3 176

56.7

208

32.9

240

14,323

3,742 49

1,215 81

470.1 113

208.9 145

103.2 177

55.7

209

32.3

241

13,681

3,602 50

1,177 82

457.5 114

204.1 146

101.1 178

54.7

210

31.8

242

13,072

3,468 51

1,140 83

445.3 115

199.4 147

99.0

179

53.7

211

31.3

243

12,493

3,340 52

1,104 84

433.4 116

194.8 148

97.0

180

52.7

212

30.8

244

11,942

3,217 53

1,070 85

421.9 117

190.3 149

95.1

181

51.8

213

30.4

245

11,419

3,099 54

1,037 86

410.8 118

186.1 150

93.2

182

50.9

214

29.9

246

10,922

2,986 55

1,005 87

400.0 119

181.9 151

91.3

183

50.0

215

29.4

247

10,450

2,878 56

973.8 88

389.6 120

177.7 152

89.5

184

49.1

216

29.0

248

10,000

2,774 57

944.1 89

379.4 121

173.7 153

87.7

185

48.3

217

28.5

249

9,572

2,675 58

915.5 90

369.6 122

169.8 154

86.0

186

47.4

218

28.1

250

9,165

2,579 59

887.8 91

360.1 123

166.0 155

84.3

187

46.6

219

8,777

2,488 60

861.2 92

350.9 124

162.3 156

82.7

188

45.8

220

8,408

2,400 61

835.4 93

341.9 125

158.6 157

81.1

189

45.0

221

8,057

2,316 62

810.6 94

333.2 126

155.1 158

79.5

190

44.3

222

7,722

2,235 63

786.6 95

324.8 127

151.7 159

78.0

191

43.5

223

Содержание 4200 Series

Страница 2: ......

Страница 3: ...ON is not responsible for any damages or losses caused to other equipment whether direct indirect incidental special or consequential which the purchaser may experience as a result of the instal lation or use of the product The buyer s sole remedy for any breach of this agreement by GEOKON or any breach of any warranty by GEOKON shall not exceed the purchase price paid by the purchaser to GEOKON f...

Страница 4: ......

Страница 5: ...E OR GROUTING 9 4 5 CABLE SPLICING AND TERMINATION 9 4 6 LIGHTNING PROTECTION 9 5 TAKING READINGS 11 5 1 MICRO 6000 DATALOGGER 11 5 2 EMBEDMENT STRAIN GAUGE READOUT POSITIONS 11 5 3 GK 404 READOUT BOX 11 5 3 1 OPERATING THE GK 404 12 5 4 GK 405 READOUT BOX 12 5 4 1 CONNECTING SENSORS WITH 10 PIN BULKHEAD CONNECTORS ATTACHED 13 5 4 2 CONNECTING SENSORS WITH BARE LEADS 13 5 4 3 OPERATING THE GK 405 ...

Страница 6: ...OUS GROWTH 18 6 9 CONVERTING STRAIN TO LOAD 18 6 10 EFFECTIVE MODULUS 18 7 TROUBLESHOOTING 19 APPENDIX A SPECIFICATIONS 21 A 1 STRAIN GAUGE 21 A 2 THERMISTOR 21 APPENDIX B THEORY OF OPERATION 22 APPENDIX C THERMISTOR TEMPERATURE DERIVATION 24 APPENDIX D HIGH TEMPERATURE THERMISTOR LINEARIZATION 25 APPENDIX E NO STRESS STRAIN ENCLOSURE 26 APPENDIX F MODEL 4200HT T HIGH TEMPERATURE STRAIN GAUGE 28 A...

Страница 7: ... FIGURE 7 MODEL 4210 VIBRATING WIRE STRAIN GAUGE 4 FIGURE 8 ADJUSTING THE RANGE OF THE STRAIN GAUGE 5 FIGURE 9 ASSEMBLED STRAIN GAUGE AND COIL HOUSING 5 FIGURE 10 ATTACHING GAUGES TO REBAR 7 FIGURE 11 SUSPENDING STRAIN GAUGES BETWEEN REBAR 8 FIGURE 12 ALTERNATIVE METHOD FOR ATTACHING GAUGES TO REBAR 8 FIGURE 13 LIGHTNING PROTECTION SCHEME 10 FIGURE 14 GK 404 READOUT 12 FIGURE 15 LEMO CONNECTOR TO ...

Страница 8: ...IN GAUGE FACTORS 15 TABLE 5 STRAIN RESOLUTION 16 TABLE 6 EFFECTIVE MODULUS 18 TABLE 7 RESISTANCE WORK SHEET 20 TABLE 8 SAMPLE RESISTANCE 20 TABLE 9 STRAIN GAUGE SPECIFICATIONS 21 TABLE 10 EMBEDMENT STRAIN GAUGE THEORETICAL PARAMETERS 22 TABLE 11 THERMISTOR RESISTANCE VERSUS TEMPERATURE 24 TABLE 12 THERMISTOR RESISTANCE VERSUS TEMPERATURE FOR MODEL 4200HT 25 ...

Страница 9: ...ON 5 TRUE LOAD RELATED STRAIN CORRECTED FOR TEMPERATURE 16 EQUATION 6 ACTUAL STRAIN 17 EQUATION 7 STRAIN TO LOAD FORMULA 18 EQUATION 8 RESISTANCE TO TEMPERATURE 24 EQUATION 9 HIGH TEMPERATURE RESISTANCE TO TEMPERATURE 25 EQUATION 10 TEMPERATURE INDUCED STRESS 29 EQUATION 11 COMBINED TEMPERATURE AND LOAD RELATED STRESS 29 EQUATION 12 EXTERNAL LOAD STRESS 29 EQUATION 13 ACTUAL STRAIN 29 ...

Страница 10: ...VI ...

Страница 11: ...red as a change in the resonant frequency of vibration of the wire Two coils one with a magnet insert the other with a pole piece insert are located close to the vibrating wire In use a pulse of varying frequency swept frequency is applied to the coils causing the wire to vibrate primarily at its resonant frequency Portable readouts and dataloggers are available from GEOKON These models when used ...

Страница 12: ...ON 2 1 MODELS 4200 AND 4200L GEOKON Models 4200 and 4200L are designed primarily for long term strain measurements inside mass concrete in structures such as foundations piles bridges dams containment vessels tunnel liners etc The 4200L is a low modulus version designed to enable early curing strains to be measured The length of the 4200 gauge is 152 mm 6 FIGURE 2 Model 4200 Vibrating Wire Strain ...

Страница 13: ...he small collar under the shrink tube at one end FIGURE 4 Model 4200 6 Vibrating Wire Strain Gauge FIGURE 5 Model 4200 7 Vibrating Wire Strain Gauge 2 3 MODEL 4202 Model 4202 is designed for direct embedment in grout mortar and small aggregate concrete It is also useful for model studies The length of the 4202 gauge is 50 mm 2 FIGURE 6 Model 4202 Vibrating Wire Strain Gauge Collar Collar ...

Страница 14: ...esigned for embedment in large aggregate concrete greater than 3 4 of an inch The standard gauge length is 254 mm 10 other gauge lengths available include Model 4212 305 mm 12 and Model 4214 356 mm 14 FIGURE 7 Model 4210 Vibrating Wire Strain Gauge ...

Страница 15: ...4000 microstrain FIGURE 8 Adjusting the Range of the Strain Gauge Model 4200 6 4200 7 Note Although the readings are taken on position D the digits shown must be converted to microstrain manually To do this multiply the observed digit change by the gauge factor given on the calibration sheet provided with the strain gauge 3 2 GAUGE AND CABLE ASSEMBLY Insert the flat part of the gauge into the slot...

Страница 16: ...the two thermistor wires usually white and green Using Table 11 on page 24 convert the resistance to temperature Compare the result to the current ambient temperature For Model 4200HT see Table 12 on page 25 3 Connect the gauge to a readout box See readout instructions Section 5 Observe the displayed readout The reading should be about the midrange position as defined in Table 2 on page 11 4 Press...

Страница 17: ...ie the instrument cable off to the rebar using nylon cable ties Note Don t tie the wires too tightly since rebar and tension cables tend to move during concrete placement and vibration Take care not to damage the cable with the vibrator The gauge can also be placed directly into the mix if it can be assured that the orientation will be correct after the gauge placement 4 2 SUSPENSION METHOD 1 Wrap...

Страница 18: ...sing nylon cable ties as shown in the figure below Then tie the strain gauge to the short pieces of rebar again using more nylon cable ties This method avoids the resonance problems associated with the previous method FIGURE 12 Alternative Method for Attaching Model 4200 4200HT Strain Gauges to Rebar Instrument Cable Coil Assembly Rebar or Tensioned Cable Wire Tie Wire Tie Rubber Tape 4200 Wire Ti...

Страница 19: ...e effect on gauge readings therefore splicing of cables has no ill effects and in some cases may be beneficial The cable used for making splices should be a high quality twisted pair type with 100 shielding and an integrated shield drain wire When splicing it is very important that the shield drain wires be spliced together Always maintain polarity by connecting color to color Splice kits recommen...

Страница 20: ...ce the board in the event that the unit is damaged by a lightning strike A connection is made between the enclosure and earth ground to facilitate the passing of transients away from the gauge See the figure below Plasma surge arrestors can be epoxied into the instrument cable close to the sensor A ground strap then connects the surge arrestor to an earth ground such as a grounding stake or the re...

Страница 21: ...ITIONS The following table indicates the readout position detail for each strain gauge model TABLE 3 Readout Positions The following sections describe how to take readings using readout equipment available from GEOKON 5 3 GK 404 READOUT BOX The Model GK 404 Vibrating Wire Readout is a portable low power hand held unit that is capable of running for more than 20 hours continuously on two AA batteri...

Страница 22: ...OS button displayed as A through F The current reading set by the MODE button displayed as a numeric value followed by the unit of measure Temperature reading of the attached instrument in degrees Celsius Use the POS and MODE buttons to select the correct position and display units for the model of equipment purchased The GK 404 will continue to take measurements and display readings until the uni...

Страница 23: ...hen twist the outer ring of the male connector until it locks into place 5 4 2 CONNECTING SENSORS WITH BARE LEADS Attach the GK 403 2 flying leads to the bare leads of a GEOKON vibrating wire sensor by connecting each of the clips on the leads to the matching colors of the sensor conductors with blue representing the shield bare 5 4 3 OPERATING THE GK 405 Press the power button on the Readout Unit...

Страница 24: ...the instrument reading in degrees Celsius 5 Press the Store button to record the value displayed If the no reading displays or the reading is unstable see Section 5 for troubleshooting suggestions The unit will automatically turn off after two minutes to conserve power For more information consult the GK 403 manual 5 6 MEASURING TEMPERATURES All GEOKON vibrating wire transducers are equipped with ...

Страница 25: ...E Reading for Models 4200 position D and 4202 position E are displayed on the readout box directly in microstrain based on the theoretical equation EQUATION 2 Theoretical Strain Where f is the frequency in digits G is the theoretical gauge factor equal to 3 304 for the 4200 gauge and 0 3910 for the 4202 gauge In practice the act of clamping shortens the vibrating wire slightly causing it to over r...

Страница 26: ... concrete expanded by exactly the same amount as the wire the wire tension would remain constant and no correction would be necessary However the steel expansion coefficient is different from the concrete expansion coefficient Due to this difference a temperature correction is required equal to EQUATION 4 Correction for Temperature Effects on the Gauge Where T0 is the initial temperature T1 is the...

Страница 27: ...ain levels of 4000 8000 and 12000 at five different temperature levels i e 40 20 0 20 40 and 60 degrees Celsius When using the polynomial expression to calculate the strain this correction factor must be applied to the current reading R1 The modified value of R1 is then inserted into the polynomial Thus the modified value of R1 to be inserted into the polynomial is R1 0 000401 R1 1 067 x T1 T0 6 6...

Страница 28: ...ulus of the structural element in the appropriate units is the strain in microstrain A is the cross sectional area in the appropriate units When installing strain gauges in concrete piles it is standard practice to install them in pairs on either side of the neutral axis This allows any strains imposed by bending to be corrected by taking the average strain of the two gauges It is also standard pr...

Страница 29: ...ng outside the specified compressive or tensile range of the instrument The gauge may have become too slack or too tight inspect the data to determine whether this is a possibility Is there a source of electrical noise nearby Likely candidates are generators motors arc welding equipment high voltage lines etc If possible move the instrument cable away from power lines and electrical equipment or i...

Страница 30: ...0HT T 120 for Model 4200HT infinite infinite infinite Black 180 50 for Models 4202 4200HT T 120 for Model 4200HT N A infinite infinite infinite White infinite infinite N A 3000 at 25 C infinite Green infinite infinite 3000 at 25 C N A infinite Shield infinite infinite infinite infinite N A Vibrating Wire Sensor Lead Grid SENSOR NAME Red Black White Green Shield Red Black White Green Shield ...

Страница 31: ...l 4200 4200 6 4200 7 4202 4204 4210 4212 4214 4200HT Range Nominal 3000 5 000 10 000 3000 Resolution 1 0 1 0 5 1 0 4 1 1 0 1 0 4 1 0 4 1 0 4 1 1 0 1 Calibration Accuracy 0 1 Full Scale Reading FSR 0 5 FSR 0 1 FSR Typical Batch Factor 0 98 N A 0 91 N A 0 95 N A N A 0 98 Batch Factor Accuracy 0 5 FSR N A 0 5 FSR System Accuracy 2 0 FSR2 Stability 0 1 Full Scale FS yr Linearity 0 5 FSR 0 3 FSR 0 5 FS...

Страница 32: ...quency of vibration of a wire is related to its tension length and mass The fundamental frequency may be determined by the equation Where Lw is the length of the wire in inches F is the wire tension in pounds m is the mass of the wire per unit length pounds seconds2 inches2 2 Note that Where W is the weight of Lw inches of wire in pounds g is the acceleration of gravity 386 inches seconds2 3 And W...

Страница 33: ... the body must equal the deformation of the wire Where Ɛ is the strain in the body Lg is the gauge length in inches 11 Combining the equations from steps nine and ten gives Where for Model 4200 Lw is 5 875 inches Lg is 6 000 inches 12 Therefore 13 The display on position D of the readout is based on the equation The squaring inverting and multiplication by the factor 3 304 109 is all done internal...

Страница 34: ...1 2 1475 42 353 4 82 110 8 122 82 87K 37 8417 3 1418 43 342 2 83 107 9 123 77 66K 36 8006 4 1363 44 331 5 84 105 2 124 72 81K 35 7618 5 1310 45 321 2 85 102 5 125 68 30K 34 7252 6 1260 46 311 3 86 99 9 126 64 09K 33 6905 7 1212 47 301 7 87 97 3 127 60 17K 32 6576 8 1167 48 292 4 88 94 9 128 56 51K 31 6265 9 1123 49 283 5 89 92 5 129 53 10K 30 5971 10 1081 50 274 9 90 90 2 130 49 91K 29 5692 11 104...

Страница 35: ... 1 530 74 571 2 106 247 0 138 119 4 170 63 3 202 36 2 234 18 971 11 4 725 43 1 480 75 555 3 107 241 1 139 116 9 171 62 1 203 35 6 235 18 090 12 4 543 44 1 432 76 539 9 108 235 3 140 114 5 172 61 0 204 35 1 236 17 255 13 4 368 45 1 385 77 525 0 109 229 7 141 112 1 173 59 9 205 34 5 237 16 463 14 4 201 46 1 340 78 510 6 110 224 3 142 109 8 174 58 8 206 33 9 238 15 712 15 4 041 47 1 297 79 496 7 111 ...

Страница 36: ...e can be used to apply corrections for these phenomena to the other strain gauges in the mass concrete allowing the user to quantify only those strains that result from stress changes INSTALLING THE 4200 4 ENCLOSURE 1 Position the enclosure inside the concrete mass with the top open so that it can be easily filled with concrete Often the 4200 4 will be placed next to a strain gauge rosette 2 Mount...

Страница 37: ...sing another tie wire and the second set of holes in the enclosure 6 Arrange the instrument cable so that it exits through the top of the enclosure 7 When pouring concrete into the enclosure remove aggregate that is too large Be careful not to disturb the gauges during the filling process ...

Страница 38: ... 17 3 C Coil resistance for Model 4200HT T is 50 ohms The thermistor included with the gauge is a high temperature thermistor which uses the resistance to temperature conversion table shown in Table 12 on page 25 When using a readout box it is not necessary to connect the green and white wires to the readout because the temperature shown on the readout will be incorrect Instead use a digital ohmme...

Страница 39: ...hanges the resulting graph will show a straight line relationship the slope of which yields a factor KT microstrain degree This factor can be used to calculate the temperature induced stress as shown by the following equation σ temperature induced KT T1 T0 E EQUATION 10 Temperature Induced Stress This can be subtracted if desired from the combined load related stress change using the following equ...

Страница 40: ...in in the concrete slab On the other hand if the concrete slab is free of all restraint and experiences a temperature change of 1 C then the concrete would expand 10 microstrains while the vibrating wire would expand 12 2 microstrains The value of R1 R0 B would then be 2 2 microstrains the vibrating wire would slacken slightly and Equation 5 would yield a value of 10 microstrains ...

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Страница 44: ...GEOKON 48 Spencer Street Lebanon New Hampshire 03766 USA Phone 1 603 448 1562 Email info geokon com Website www geokon com GEOKON is an ISO 9001 2015 registered company ...

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