Geokon 6350 Installation Manual

Vibrating wire tiltmeter
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Installation Manual
Model 6350
Vibrating Wire Tiltmeter
No part of this instruction manual may be reproduced, by any means, without the written consent of Geokon, Inc.
The information contained herein is believed to be accurate and reliable. However, Geokon, Inc. assumes no responsibility for
errors, omissions, or misinterpretation. The information herein is subject to change without notification.
Copyright © 1995-2018 by Geokon, Inc.
(Doc Rev P, 06/28/18)

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Summary of Contents for Geokon 6350

  • Page 1 Vibrating Wire Tiltmeter No part of this instruction manual may be reproduced, by any means, without the written consent of Geokon, Inc. The information contained herein is believed to be accurate and reliable. However, Geokon, Inc. assumes no responsibility for errors, omissions, or misinterpretation.
  • Page 3 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...
  • Page 5: Table Of Contents

    TABLE of CONTENTS 1. INTRODUCTION ..............................1 1.1 T ............................1 HEORY OF PERATION 1.2 T ..........................2 ENSOR ONSTRUCTION 2. INSTALLATION ..............................3 2.1 P ............................3 RELIMINARY ESTS 2.2 I ......................4 NSTALLING THE OUNTING RACKETS 2.2.1 Mounting with a Drop-in Anchor ........................ 4 2.2.2 Mounting with an Anchor Rod ........................
  • Page 6 FIGURES 1 - M 6350 U ..................1 IGURE ODEL NIAXIAL ILTMETER NSTALLATION 2 - M 6350 T .......................... 2 IGURE ODEL ENSOR 3 - T ......................4 IGURE ILTMETER OUNTING RACKETS 4 - D ) ..........5 IGURE NCHOR...
  • Page 7: Introduction

    1. INTRODUCTION 1.1 Theory of Operation The Geokon Model 6350 Vibrating Wire Tiltmeter is designed for permanent long-term monitoring of changes in tilt of structures such as dams, embankments, foundation walls and the like. The basic principle is the utilization of tilt sensors attached to the structure being studied to make accurate measurement of inclination.
  • Page 8: Tilt Sensor Construction

    90° to each other. In environments subject to vibrations, a damping fluid can be used, as shown in the figure below. Figure 2 - Model 6350 Tilt Sensor To prevent damage during shipment the tilt sensors are locked in place by means of a slotted head locking clamp screw.
  • Page 9: Installation

    2. INSTALLATION 2.1 Preliminary Tests Prior to installation, the sensors need to be checked for proper operation. Each tilt sensor is supplied with a calibration report, which shows the relationship between readout digits and inclination. The tilt sensor electrical leads (usually the red and black leads) are connected to a readout box (see Section 3 for readout instructions) and the current reading compared to the calibration readings.
  • Page 10: Installing The Mounting Brackets

    2.2 Installing the Mounting Brackets Two mounting brackets are available for the Model 6350. One is designed for uniaxial tilt measurements the other for biaxial. Figure 3 - Tiltmeter Mounting Brackets Both bracket types may be mounted using a drop-in anchor or an anchor rod that is epoxied or grouted in place.
  • Page 11: Mounting With An Anchor Rod

    6) Attach the mounting bracket to the bolt using the supplied hardware, as illustrated in Figure 4. 7) Use a leveling device to align the bracket vertically to the wall. Top View Wall Flat Washers Flat Washer 3/8-16 Nuts Lock Washer 2"...
  • Page 12: Figure 5 - Anchor Rod

    7) After setting, attach the mounting bracket to the bolt using the supplied hardware as illustrated in Figure 5. 8) Use a bubble level or other leveling device to align the bracket vertically to the wall. Wall Flat Washers 1/2-13 Nuts 4"...
  • Page 13: Sensor Installation

    2.3 Sensor Installation 2.3.1 Installing Uniaxial Tiltmeters Attach the tiltmeter to the mounting bracket using the supplied 10-32 cap screws, washers, and nuts. Remove the slotted head locking clamp screw completely and replace with the Phillips head seal screw (provided). This is very important if the sensor is to remain waterproof.
  • Page 14: Installing Biaxial Tiltmeters

    2.2.2 Installing Biaxial Tiltmeters The sensors may now be installed. Attach the tiltmeters to the mounting bracket using the supplied 10-32 cap screws, washers, and nuts. Remove the slotted head locking clamp screw completely and replace with the Phillips head seal screw provided. This is very important if the sensor is to remain waterproof.
  • Page 15: Fluid Damping

    4) The sensor may now be attached to the mounting bracket. 2.5 Splicing and Junction Boxes Terminal boxes with sealed cable entries are available from Geokon for all types of applications. These allow many gages to be terminated at one location with complete protection of the lead wires.
  • Page 16: Lightning Protection

    Splice kits recommended by Geokon incorporate casts, which are placed around the splice and are then filled with epoxy to waterproof the connections. When properly made, this type of splice is equal or superior to the cable in strength and electrical properties. Contact Geokon for splicing materials and additional cable splicing instructions.
  • Page 17: Taking Readings

    20 hours continuously on two AA batteries. It is designed for the readout of all Geokon vibrating wire gages and transducers, and is capable of displaying the reading in either digits, frequency (Hz), period (µs), or microstrain (µε). The GK-404 also displays the temperature of the transducer (embedded thermistor) with a resolution of 0.1 °C.
  • Page 18: Gk-405 Readout Box

    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).
  • Page 19: Gk-403 Readout Box (Obsolete Model)

    3.3.2 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).
  • Page 20: Micro-10 Datalogger

    3.4 MICRO-10 Datalogger The following parameters are recommended when using the Model 6350 with the MICRO-10 datalogger or any other CR10 based datalogger: 3.4.1 Excitation The 2.5V excitation directly off the wiring panel is ideal for these sensors. The five volt supply from the AVW-1 and AVW-4 modules is also usable, but the 12V excitation should be avoided as it tends to overdrive the sensor.
  • Page 21: Data Reduction

    – R 4.2 Temperature Correction The Model 6350 Tiltmeter has a very slight temperature sensitivity on the order of – 0.5 digit per °C rise, i.e. the reading falls by 0.5 digits for every 1 °C rise of temperature. The temperature...
  • Page 22: Troubleshooting

    Gages should not be opened in the field. Should difficulties arise, consult the following list of problems and possible solutions. For additional troubleshooting and support, contact Geokon. Symptom: Thermistor resistance is too high:  Is there an open circuit? Check all connections, terminals, and plugs. If a cut is located in the cable, splice according to instructions in Section 2.4.
  • Page 23: Table 1 - Sample Resistance

    Vibrating Wire Sensor Lead Grid - SAMPLE VALUES Black White Green Shield ≅180Ω infinite infinite infinite ≅180Ω Black infinite infinite infinite 3000Ω at 25°C White infinite infinite infinite 3000Ω at 25°C Green infinite infinite infinite Shield infinite infinite infinite infinite Table 1 - Sample Resistance Vibrating Wire Sensor Lead Grid - SENSOR NAME/## : Black...
  • Page 24: Appendix A. Sample Calibration Report

    APPENDIX A. SAMPLE CALIBRATION REPORT Figure 11 - Sample Model 6350 Calibration Report...
  • Page 25: Appendix B. Specifications

    Electrical Cable: Two twisted pair (four conductor) 22 AWG Foil shield, PVC jacket, nominal OD=6.3 mm (0.250") Table 3 - Model 6350 Tilt Sensor Specifications Notes: ¹ Consult the factory for other ranges. ² Depends on readout equipment. With averaging techniques, it is possible to achieve one arc second ³...
  • Page 26: Appendix C. Thermistor Temperature Derivation

    APPENDIX C. THERMISTOR TEMPERATURE DERIVATION Thermistor Type: YSI 44005, Dale #1C3001-B3, Alpha #13A3001-B3 Resistance to Temperature Equation: A+B ( LnR ) +C(LnR) -273.2 Equation 4 - Resistance to Temperature Where; T = Temperature in °C. LnR = Natural Log of Thermistor Resistance A = 1.4051 ×...

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