Related Manuals for Geokon 4200 Series
Summary of Contents for Geokon 4200 Series
- Page 1 Model 4200 Series Vibrating Wire Strain Gauges Instruction Manual ©2018, GEOKON. All rights reserved. Document Revision: BB | Release date: 12/4/18...
- Page 3 WARRANTY STATEMENT warrants its products to be free of defects in materials and workmanship, GEOKON under normal use and service for a period of 13 months from date of purchase. If the unit should malfunction, it must be returned to the factory for evaluation, freight prepaid.
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Page 5: Table Of Contents
TABLE OF CONTENTS 1. INTRODUCTION ............................2. MODELS ................................2.1 MODELS 4200 AND 4200L ......................2.2 MODELS 4200-6 AND 4200-7 ....................2.3 MODEL 4202 ............................2.4 MODEL 4210 ............................3. PRIOR TO INSTALLATION ....................... 3.1 ADJUSTING GAUGE TO THE DESIRED RANGE ............ - Page 6 6.1 READOUT BOX POSITION A ....................6.2 READOUT BOX POSITION B ....................6.3 READOUT BOX POSITIONS D & E ..................6.4 STRAIN RESOLUTION ........................6.5 TEMPERATURE CORRECTIONS ..................6.5.1 MODEL 4200-6 / 4200-7 CORRECTIONS ................6.6 SHRINKAGE EFFECTS ........................6.7 CREEP EFFECTS ..........................
- Page 7 FIGURES FIGURE 1: ON-SITE INSTALLATION PHOTO ..............1 FIGURE 2: MODEL 4200 VIBRATING WIRE STRAIN GAUGE .........2 FIGURE 3: MODEL 4200L VIBRATING WIRE STRAIN GAUGE ........2 FIGURE 4: MODEL 4200-6 VIBRATING WIRE STRAIN GAUGE ........3 FIGURE 5: MODEL 4200-7 VIBRATING WIRE STRAIN GAUGE ........3 FIGURE 6: MODEL 4202 VIBRATING WIRE STRAIN GAUGE .........3 FIGURE 7: MODEL 4210 VIBRATING WIRE STRAIN GAUGE .........4 FIGURE 8: ADJUSTING THE RANGE OF THE STRAIN GAUGE ........5...
- Page 8 TABLES TABLE 1: HEAT SHRINK COLOR DESIGNATIONS............2 TABLE 2: EMBEDMENT STRAIN GAUGE DATALOGGER PARAMETERS....11 TABLE 3: READOUT POSITIONS..................11 TABLE 4: EMBEDMENT STRAIN 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...
- Page 9 EQUATIONS EQUATION 1: PERIOD TO DIGITS CONVERSION............15 EQUATION 2: THEORETICAL STRAIN ................15 EQUATION 3: APPARENT STRAIN................... 15 EQUATION 4: CORRECTION FOR TEMPERATURE EFFECTS ON THE GAUGE.... 16 EQUATION 5: TRUE, LOAD-RELATED STRAIN CORRECTED FOR TEMPERATURE ..16 EQUATION 6: ACTUAL STRAIN..................17 EQUATION 7: STRAIN TO LOAD FORMULA ..............
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Page 11: Introduction
Note: Do not rotate or pull on the gauge end blocks, because this will alter the readings and may cause permanent damage. FIGURE 1: On-site Installation Photo MODEL 4200 SERIES STRAIN GAUGES | INTRODUCTION | 1... -
Page 12: Models
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 Gauge FIGURE 3: Model 4200L Vibrating Wire Strain Gauge 2 | MODELS | GEOKON... -
Page 13: Models 4200-6 And 4200-7
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 MODEL 4200 SERIES STRAIN GAUGES | MODELS | 3... -
Page 14: Model 4210
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 4 | MODELS | GEOKON... -
Page 15: Prior To Installation
A preliminary check should be performed before installing the gauge in the field. To perform the preliminary check, complete the following steps: Using an ohmmeter, check the resistance between the two lead wires (usually red and black). MODEL 4200 SERIES STRAIN GAUGES | PRIOR TO INSTALLATION | 5... - Page 16 Table 2 on page 11. Press on the gauge ends and confirm that it makes the reading decrease. Return any faulty gauges to the factory. Gauges should not be opened in the field. 6 | PRIOR TO INSTALLATION | GEOKON...
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Page 17: Installing The Gauges In Concrete
Position the gauge between the rebar and twist the wire ends twice around the rebar, then around itself. Tighten the wire and orient the gauge by twisting the loops between the gauge and the rebar. MODEL 4200 SERIES STRAIN GAUGES | INSTALLING THE GAUGES IN CONCRETE | 7... -
Page 18: Alternative Suspension Method
Instrument Cable Nylon Cable Ties Nylon Cable Ties Short Lengths of Rebar Nylon Cable Ties FIGURE 12: Alternative Method for Attaching Model 4200/4200HT Strain Gauges to Rebar 8 | INSTALLING THE GAUGES IN CONCRETE | GEOKON... -
Page 19: Using Pre-Cast Briquettes, Shotcrete, Or Grouting
In addition, if the instrument cable is exposed, it may be appropriate to install lightning protection components, as the transient could travel down the cable to the gauge and possibly destroy it. MODEL 4200 SERIES STRAIN GAUGES | INSTALLING THE GAUGES IN CONCRETE | 9... -
Page 20: Figure 13: Lightning Protection Scheme
A ground strap then connects the surge arrestor to an earth ground, such as a grounding stake or the rebar itself. Consult the factory for additional information on available lightning protection. FIGURE 13: Lightning Protection Scheme 10 | INSTALLING THE GAUGES IN CONCRETE | GEOKON... -
Page 21: Taking Readings
TAKING READINGS 5.1 MICRO-6000 DATALOGGER recommends the parameters in the table below when using strain GEOKON gauges with the MICRO-6000 datalogger or any other CR1000 based datalogger. It shows the recommended gauge type selection and gauge factor G entry to convert to microstrain. The table also lists the starting and ending frequency settings for the excitation sweep when writing a program for the CR1000 using the P28 vibrating wire measurement instruction. -
Page 22: Operating The Gk-404
The GK-405 Remote Module, which is housed in a weather-proof enclosure. The remote module can be wire-connected to the sensor by means of: Flying leads with alligator clips, if the sensor cable terminates in bare wires. 12 | TAKING READINGS | GEOKON... -
Page 23: Connecting Sensors With 10-Pin Bulkhead Connectors
5.4.2 CONNECTING SENSORS WITH BARE LEADS Attach the GK-403-2 flying leads to the bare leads of a vibrating wire GEOKON sensor by connecting each of the clips on the leads to the matching colors of the sensor conductors, with blue representing the shield (bare). -
Page 24: Gk-403 Readout Box (Obsolete Model)
14.7 per 1000 feet (48.5 per km) at 20 °C. Multiply these factors by two to account for both directions. Look up the temperature for the measured resistance in Appendix C. For the 4200HT use Appendix D. 14 | TAKING READINGS | GEOKON... -
Page 25: Data Reduction
B – apparent EQUATION 3: Apparent Strain Where: is the initial reading is the current reading from the readout box, taken in position D or E. MODEL 4200 SERIES STRAIN GAUGES | DATA REDUCTION | 15... -
Page 26: Table 5: Strain Resolution
) is positive, the strain is tensile. B is the batch gauge factor suppled with each gauge. and C are the same values as shown in Equation 4 on page 16. A theoretical example of the above is shown below. 16 | DATA REDUCTION | GEOKON... -
Page 27: Equation 6: Actual Strain
6.7 CREEP EFFECTS It is also well-known that concrete will creep under a sustained load. What may seem to be a gradually increasing load, as evidenced by a gradually-increasing MODEL 4200 SERIES STRAIN GAUGES | DATA REDUCTION | 17... -
Page 28: Table 6: Effective Modulus
E, approximate Model 4200 596,000 psi 4200L 56,500 psi 4200-6 / 4200-7 4200HT 596,000 psi 4200HT-T 11,950,000 psi 4202 610,000 psi 4204 596,000 psi 4210 / 4212 / 4214 2,350,000 psi TABLE 6: Effective Modulus 18 | DATA REDUCTION | GEOKON... -
Page 29: Troubleshooting
Section 4.5. Does the readout or datalogger work with another gauge? If not, it may have a low battery or possibly be malfunctioning. MODEL 4200 SERIES STRAIN GAUGES | TROUBLESHOOTING | 19... -
Page 30: Table 7: Resistance Work Sheet
3000 at 25 °C infinite Shield infinite infinite infinite infinite TABLE 7: Sample Resistance Vibrating Wire Sensor Lead Grid - SENSOR NAME/## Black White Green Shield Black White Green Shield TABLE 8: Resistance Work Sheet 20 | TROUBLESHOOTING | GEOKON... -
Page 31: Appendix A. Specifications
Model 4200HT-T high-temperature strain gauge has a Thermal Coefficient of 17.3 / °C. A.2 THERMISTOR For more information, refer to Appendix C. Range: -80 to +150 °C Accuracy: ±0.5 °C MODEL 4200 SERIES STRAIN GAUGES | SPECIFICATIONS | 21... -
Page 32: Appendix B. Theory Of Operation
Combining the equations from steps one, two, and three gives: Note that the tension (F) can be expressed in terms of strain, e.g., Where: Ɛ is the wire strain (inches/inches). E is the Young’s Modulus of the wire (30 x 10 Psi). 22 | THEORY OF OPERATION | GEOKON... - Page 33 Note: In the previous steps, T is seconds x 10 and ε is microinches per inch. An alternative is: ε = 3.304 x 10 microstrain. Where f is the frequency in Hz. MODEL 4200 SERIES STRAIN GAUGES | THEORY OF OPERATION | 23...
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Page 34: Table 11: Thermistor Resistance Versus Temperature
64.0 21.89K 3000 624.7 176.4 62.5 20.70K 2872 603.3 171.4 61.1 19.58K 2750 582.6 166.7 59.6 18.52K 2633 562.8 162.0 58.3 17.53K 2523 543.7 157.6 56.8 55.6 TABLE 11: Thermistor Resistance versus Temperature 24 | THERMISTOR TEMPERATURE DERIVATION | GEOKON... -
Page 35: Appendix D. High-Temperature Thermistor Linearization
2,316 62 810.6 94 333.2 126 155.1 158 79.5 44.3 7,722 2,235 63 786.6 95 324.8 127 151.7 159 78.0 43.5 TABLE 12: Thermistor Resistance versus Temperature for Model 4200HT MODEL 4200 SERIES STRAIN GAUGES | HIGH-TEMPERATURE THERMISTOR LINEARIZATION | 25... -
Page 36: Figure 17: No Stress Strain Enclosure
Wrap the ends of the tie wire around the outside of the enclosure and tie together. Use a tie wire tightening tool or similar device to tighten the wire. 26 | NO STRESS STRAIN ENCLOSURE | GEOKON... - Page 37 Arrange the instrument cable so that it exits through the top of the enclosure. When pouring concrete into the enclosure, remove aggregate that is too large. Be careful not to disturb the gauges during the filling process. MODEL 4200 SERIES STRAIN GAUGES | NO STRESS STRAIN ENCLOSURE | 27...
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Page 38: Gauge
(Since the resistance changes with temperature are large, the effect of cable resistance is usually insignificant.) Look up the temperature for the measured resistance in Table 12 on page 25. 28 | MODEL 4200HT-T HIGH-TEMPERATURE STRAIN GAUGE | GEOKON... -
Page 39: Appendix G. Measurement And Correction Of Temperature Effects
If the temperature rises by one C, then the vibrating wire undergoes an expansion of 12.2 microstrains and MODEL 4200 SERIES STRAIN GAUGES | MEASUREMENT AND CORRECTION OF TEMPERATURE EFFECTS | 29... - Page 40 12.2 microstrains. The value of (R would then be -2.2 microstrains (the vibrating wire would slacken slightly), and Equation 5 would yield a value of 10 microstrains. 30 | MEASUREMENT AND CORRECTION OF TEMPERATURE EFFECTS | GEOKON...
- Page 44 GEOKON Phone: +1 (603) 448-1562 GEOKON 48 Spencer Street Email: info@geokon.com is an ISO 9001:2015 Lebanon, New Hampshire Website: www.geokon.com registered company 03766, USA...