Geokon 4425 Instruction Manual Download Page 22

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Vibrating Wire Sensor Lead Grid - SAMPLE VALUES

Red

Black

White

Green

Shield

Red

N/A

≅180Ω

infinite

Black

≅180Ω

N/A

infinite

White

infinite

N/A

3000Ω

25°

infinite

Green

infinite

3000Ω

25°

N/A

infinite

Shield

infinite

N/A

Table 7 - Sample Resistance

Vibrating Wire Sensor Lead Grid - SENSOR NAME/## :

Red

Black

White

Green

Shield

Red

Black

White

Green

Shield

Table 8 - Resistance Work Sheet

Summary of Contents for 4425

Page 1: ...eans without the written consent of Geokon The information contained herein is believed to be accurate and reliable However Geokon assumes no responsibility for errors omissions or misinterpretation The information herein is subject to change without notification Copyright 1985 2019 by Geokon Doc Rev O 2 21 2019 ...

Page 2: ......

Page 3: ...nnel There are no warranties except as stated herein There are no other warranties expressed or implied including but not limited to the implied warranties of merchantability and of fitness for a particular purpose Geokon 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 ...

Page 4: ......

Page 5: ...OX OBSOLETE MODEL 8 3 3 1 Connecting Sensors with 10 pin Bulkhead Connectors Attached 8 3 3 2 Connecting Sensors with Bare Leads 8 3 3 3 Operating the GK 403 8 3 4 MEASURING TEMPERATURES 8 4 DATA REDUCTION 9 4 1 DIGITS 9 4 2 TEMPERATURE CORRECTION 10 4 3 ROD STRETCH CORRECTION 11 4 4 CORRECTION FOR SAG 12 4 5 ENVIRONMENTAL FACTORS 14 5 TROUBLESHOOTING 15 APPENDIX A SPECIFICATIONS 17 A 1 MODEL 4425...

Page 6: ... 1 CONVERGENCE METER LENGTH 3 TABLE 2 ENGINEERING UNITS CONVERSION MULTIPLIERS 9 TABLE 3 TRANSDUCER THERMAL COEFFICIENT CALCULATION CONSTANTS 10 TABLE 4 YOUNG S MODULUS AND THERMAL COEFFICIENTS 11 TABLE 5 SPRING RATES 12 TABLE 6 DENSITIES 12 TABLE 7 SAMPLE RESISTANCE 16 TABLE 8 RESISTANCE WORK SHEET 16 TABLE 9 THERMISTOR RESISTANCE VERSUS TEMPERATURE 18 EQUATIONS EQUATION 1 DIGITS CALCULATION 9 EQ...

Page 7: ...ated stress relieved spring which is connected to the wire at one end and a connecting rod at the other The unit is fully sealed and operates at pressures of up to 250 psi As the connecting rod is pulled out from the gauge body the spring is elongated causing an increase in tension which is sensed by the vibrating wire element The tension in the wire is directly proportional to the extension so th...

Page 8: ...vergence Meter Installation 1 The first step is to unpack all the various components and lay them on a flat surface in their relative positions Refer to Figure 1 in Section 1 2 Next the two anchor points must be installed When the locations have been decided drill holes to accommodate the anchors Cement the eyebolt anchors in place using quick set hydraulic cement or epoxy Allow the cement or epox...

Page 9: ...into the fitting until it hits the stop Tighten the Swagelok connector according to the instructions in Appendix C Connect the second and successive rods using the Swagelok fittings as described above 7 Connect the Swagelok eyehook to one end of the rods and the convergence meter to the other 8 Hook the eyehook end into the installed eyebolt first 9 Hook the convergence meter into the other eyebol...

Page 10: ...e from sources of electrical interference such as power lines generators motors transformers arc welders etc Cables should never be buried or run with AC power lines The instrument cables will pick up the 50 or 60 Hz or other frequency noise from the power cable and this will likely cause a problem obtaining a stable reading Contact the factory concerning filtering options available for use with t...

Page 11: ...dings therefore splicing of cables has no ill effects and in some cases may in fact be beneficial The cable used for making splices should be a high quality twisted pair type with 100 shielding and an integral 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 recommended by Geokon i...

Page 12: ...r conductors with blue representing the shield bare To turn the GK 404 on press the ON OFF button on the front panel of the unit The initial startup screen will display Geokon Inc GK 404 verX XX After approximately one second the GK 404 will start taking readings and display them based on the settings of the POS and MODE buttons The unit display from left to right is as follows The current Positio...

Page 13: ...ale connector until it locks into place 3 2 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 3 2 3 Operating the GK 405 Press the button labeled POWER ON BLUETOOTH A blue light will begin blinkin...

Page 14: ...layed above the gauge reading in degrees centigrade 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 approximately two minutes to conserve power 3 4 Measuring Temperatures Each Vibrating Wire Convergence Meter is equipped with a thermistor for reading...

Page 15: ...libration factor usually in terms of millimeters or inches per digit taken from the calibration report an example of which is shown in Appendix D F is an engineering units conversion factor optional see Table 2 From To Inches Feet Millimeters Centimeters Meters Inches 1 12 0 03937 0 3937 39 37 Feet 0 0833 1 0 003281 0 03281 3 281 Millimeters 25 4 304 8 1 10 1000 Centimeters 2 54 30 48 0 10 1 100 M...

Page 16: ...e thermal coefficient of the turnbuckle spring 0 0007 or 0 0178 mm C Tests have determined that the transducer thermal coefficient K changes with the position of the transducer shaft The first step in the temperature correction process is determination of the proper transducer thermal coefficient based on the following equation K R1 M B G Equation 4 Transducer Thermal Coefficient Calculation Where...

Page 17: ...ay and through the seasons and allow corrections for these effects to be accurately made 4 3 Rod Stretch Correction Rod Stretch PL aE Equation 6 Rod Stretch Where P is the rod tension lb or Newtons L is the rod length inches or mm a is the rod area of cross section sq inches or square mm E is the Young s modulus lb sq inch or MPa P depends on the spring rate S of the large exterior tension spring ...

Page 18: ...LW2 24P2 or L3 ω2 24P2 Equation 8 Sag Correction Where L length of rods The distance over which the measurement is made W weight of rods P tension The springs used have an initial tension of 13 lb 57 8N and this must be added to the force caused by the displacement SD ω weight of rods per unit length see Table 6 For convergence the correction is negative for extensions the correction is positive R...

Page 19: ...g at T1 is 60 x 4 24 x 30 x 30 0 0111 f t 0 133 inches So after correction for sag the true convergence is 1 0 133 0 054 0 921 inches Summing all the various effects Dcorrected Duncorrected Dtemperature Drodstretch Dsag Equation 9 Corrected Deformation Again consider the following example from a Model 4425 12 Convergence Meter attached to 30 meters of 1 4 inch diameter graphite rod R0 4919 digits ...

Page 20: ...918 10 29 mm 4 5 Environmental Factors Since the purpose of the convergence meter installation is to monitor site conditions factors that may affect these conditions should always be observed and recorded Seemingly minor effects may have a real influence on the behavior of the structure being monitored and may give an early indication of potential problems Some of these factors include but are not...

Page 21: ... retracted with the alignment pin inside the alignment slot as shown in Figure 1 the readings will likely be unstable because the transducer is now out of range Is there a source of electrical noise nearby Most probable sources of electrical noise are motors generators transformers arc welders and antennas Make sure the shield drain wire is connected to ground whether using a portable readout or d...

Page 22: ... infinite infinite infinite White infinite infinite N A 3000Ω at 25 C infinite Green infinite infinite 3000Ω at 25 C N A infinite Shield infinite infinite infinite infinite N A Table 7 Sample Resistance Vibrating Wire Sensor Lead Grid SENSOR NAME Red Black White Green Shield Red Black White Green Shield Table 8 Resistance Work Sheet ...

Page 23: ...ge 115 FSR Temperature Range 40 to 60 C 40 to 120 F Frequency Range 1200 2800 Hz Coil Resistance 180 Ω 10 Ω Cable Type Two twisted pair four conductor 22 AWG Foil shield PVC jacket nominal OD 6 3 mm 0 250 Convergence Meter Length including Swagelok eyehook assembly 710 mm 28 710 mm 28 865 mm 34 1195 mm 47 1615 mm 63 5 Notes Minimum greater resolution possible depending on readout Depends on applic...

Page 24: ...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 1040 51 266 6 91 87 9 131 46 94K 28 5427 12 1002 52 258 6 92 85...

Page 25: ...l as high safety factor systems further tighten the nut until the tube will not turn by hand or move axially in the fitting 3 Mark the nut at the six o clock position Figure 8 Make a Mark at Six O clock 4 While holding the fitting body steady tighten the nut one and one quarter turns until the mark is at the nine o clock position Note For 1 16 1 8 3 16 and 2 3 and 4 mm fittings tighten the nut thr...

Page 26: ... Inspect the ferrules for damage and replace if necessary If the ferrules are replaced the connector should be treated as a new assembly Refer to the section above for installation instructions 4 Reassemble the fitting by inserting the tube with preswaged ferrules into the fitting until the front ferrule seats against the fitting body Figure 11 Ferrules Seated Against Fitting Body 5 While holding ...

Page 27: ...21 APPENDIX D EXAMPLE CALIBRATION REPORT Figure 13 Typical 4425 Calibration Report ...

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Geokon 4425, Instruction Manual, Page: 22 / 27

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