Geokon 4900 Manuel utilisateur
©2021, GEOKON. All rights reserved.
Document Revision: BB | Release date: 03/10/21
Model 4900
Vibrating Wire Load Cell
Instruction Manual
WARRANTY STATEMENT
GEOKON warrants its products to be free of defects in materials and workmanship,
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. Upon examination by GEOKON, if the unit is found to be defective, it will be
repaired or replaced at no charge. However, the WARRANTY IS VOID if the unit shows
evidence of having been tampered with or shows evidence of being damaged as a
result of excessive corrosion or current, heat, moisture or vibration, improper specifi-
cation, misapplication, misuse or other operating conditions outside of GEOKON's
control. Components that wear or are damaged by misuse are not warranted. This
includes fuses and batteries.
GEOKON manufactures scientific instruments whose misuse is potentially dangerous.
The instruments are intended to be installed and used only by qualified personnel.
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 merchant-
ability 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 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 for the unit or units, or equipment directly
affected by such breach. Under no circumstances will GEOKON reimburse the
claimant for loss incurred in removing and/or reinstalling equipment.
Every precaution for accuracy has been taken in the preparation of manuals and/or
software, however, GEOKON neither assumes responsibility for any omissions or
errors that may appear nor assumes liability for any damages or losses that result
from the use of the products in accordance with the information contained in the
manual or software.
No part of this instruction manual may be reproduced, by any means, 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.
The GEOKON® wordmark and logo are registered trademarks with the United States Patent and Trademark Office.
I
TABLE OF CONTENTS
1. INTRODUCTION............................................................................................................................................1
1.1 THEORY OF OPERATION...............................................................................................................1
1.2 LOAD CELL DESIGN AND CONSTRUCTION ................................................................2
1.2.1 FRICTION BETWEEN THE BEARING PLATE AND LOAD CELL.......................................3
1.2.2 WARPING OF THE BEARING PLATES AND BEARING PLATE DESIGN ......................4
1.2.3 ECCENTRIC LOADING .....................................................................................................................4
1.2.4 ELASTIC BEHAVIOR .........................................................................................................................5
1.2.5 TEMPERATURE EFFECTS...............................................................................................................5
2. INSTALLATION..............................................................................................................................................6
2.1 PRELIMINARY TESTS......................................................................................................................6
2.2 LOAD CELL INSTALLATION .......................................................................................................6
2.2.1 TRANSPORTATION...........................................................................................................................6
2.2.2 INITIAL NO-LOAD READING.........................................................................................................6
2.2.3 INSTALLATION ON TIE-BACKS AND ROCKBOLTS .............................................................6
2.3 CABLE INSTALLATION AND SPLICING ..........................................................................6
2.4 ELECTRICAL NOISE ...........................................................................................................................7
2.5 ENVIRONMENTAL FACTORS ....................................................................................................7
2.6 LIGHTNING PROTECTION............................................................................................................7
3. TAKING READINGS .................................................................................................................................9
3.1 GK-404 VIBRATING WIRE READOUT................................................................................9
3.1.1 OPERATING THE GK-404 ...............................................................................................................9
3.2 GK-405 VIBRATING WIRE READOUT............................................................................ 10
3.2.1 CONNECTING SENSORS WITH 10-PIN BULKHEAD CONNECTORS
ATTACHED ....................................................................................................................................... 10
3.2.2 CONNECTING SENSORS WITH BARE LEADS................................................................... 10
3.2.3 OPERATING THE GK-405 ........................................................................................................... 10
3.2.4 READOUT IN LOAD UNITS........................................................................................................ 11
3.3 MEASURING TEMPERATURES ........................................................................................... 12
4. DATA REDUCTION ................................................................................................................................13
4.1 LOAD CALCULATION ................................................................................................................... 13
4.2 TEMPERATURE CORRECTION FACTOR ...................................................................... 14
5. TROUBLESHOOTING .......................................................................................................................... 16
APPENDIX A. SPECIFICATIONS .................................................................................................. 17
A.1 MODEL 4900 LOAD CELL SPECIFICATIONS.......................................................... 17
A.2 THERMISTOR...................................................................................................................................... 17
II
APPENDIX B. THERMISTOR TEMPERATURE DERIVATION ....................... 18
APPENDIX C. WIRING AND CONNECTOR PINOUTS.......................................... 19
C.1 LOAD CELL CONNECTOR AND CABLE (STANDARD WIRING)............... 19
C.2 GK-403 TO MODULE CONNECTOR ................................................................................. 19
APPENDIX D. LOAD CELL GAUGE FACTOR RECALCULATION............... 20
D.1 OVERVIEW ............................................................................................................................................. 20
D.2 PROCEDURE......................................................................................................................................... 20
APPENDIX E. LOAD CELL CALIBRATIONS - EFFECTS OF
BEARING PLATE WARPING...................................................................... 21
E.1 INTRODUCTION................................................................................................................................. 21
E.2 LOAD CELL CALIBRATION PROCEDURES................................................................. 21
E.3 FIELD ARRANGEMENT................................................................................................................ 21
E.4 EFFECTS OF JACK SIZE ON LOAD CELL READING .......................................... 21
E.5 CONCLUSION....................................................................................................................................... 22
APPENDIX F. USE OF THE REGRESSION ZERO WHEN USING
THE LINEAR GAUGE FACTOR................................................................. 23
APPENDIX G. MODEL 8032-27 AND LOAD CELL WIRING.......................... 24
III
FIGURES
FIGURE 1: LOAD CELLS ON TIEBACKS FOR MONITORING ...........................................1
FIGURE 2: LOAD CELLS ON TIEBACKS FOR TESTING ....................................................2
FIGURE 3: LOAD CELLS FOR LOAD MONITORING DURING PILE LOAD TEST .............2
FIGURE 4: MODEL 4900 LOAD CELL SIDE VIEW ...........................................................3
FIGURE 5: TYPICAL LOAD CELL SYSTEM ........................................................................3
FIGURE 6: GK-404 READOUT ...........................................................................................9
FIGURE 7: LEMO CONNECTOR TO GK-404 .....................................................................9
FIGURE 8: GK-405 READOUT .........................................................................................10
FIGURE 9: TYPICAL MODEL 4900 CALIBRATION SHEET .............................................15
FIGURE 10: MODEL 8032-27 JUMPER WIRE ASSEMBLY ...........................................24
IV
TABLES
TABLE 1: ENGINEERING UNITS CONVERSION MULTIPLIERS....................................13
TABLE 2: MODEL 4900 LOAD CELL SPECIFICATIONS.................................................17
TABLE 3: 3KΩ THERMISTOR RESISTANCE....................................................................18
TABLE 4: STANDARD LOAD CELL WIRING ...................................................................19
TABLE 5: MODULE WIRING.............................................................................................19
TABLE 6: GAUGE FACTOR FOR REMAINING GAUGES................................................20
TABLE 7: EFFECTS OF JACK SIZING ON READINGS ...................................................22
V
EQUATIONS
EQUATION 1: DIGITS CALCULATION .............................................................................. 13
EQUATION 2: LOAD CALCULATION USING LINEAR REGRESSION............................. 13
EQUATION 3: LOAD CALCULATION USING POLYNOMIAL .......................................... 14
EQUATION 4: LOAD, CORRECTED FOR TEMPERATURE .............................................. 14
EQUATION 5: 3KΩ THERMISTOR RESISTANCE............................................................. 18
VI
Table des matières
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