Geokon 4410 User manual

Instruction Manual
Model 4410
Vibrating Wire Strandmeter
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 © 1994-2017 by Geokon, Inc.
(Doc Rev N, 11/27/17)

Warranty Statement
Geokon, Inc. 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 specification, misapplication, misuse or other operating conditions outside
of Geokon's control. Components which wear or which 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 merchantability and of fitness for a particular
purpose. Geokon, Inc. 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 installation or use of the product. The buyer's sole remedy for any breach of this
agreement by Geokon, Inc. or any breach of any warranty by Geokon, Inc. shall not exceed the
purchase price paid by the purchaser to Geokon, Inc. 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, Inc. 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.

TABLE of CONTENTS
1. INTRODUCTION...................................................................................................................................................1
1.1 THEORY OF OPERATION.......................................................................................................................................1
2. INSTALLATION ....................................................................................................................................................2
2.1 PRELIMINARY TESTS............................................................................................................................................2
2.2 STRANDMETER INSTALLATION ............................................................................................................................2
2.3 ELECTRICAL NOISE..............................................................................................................................................3
2.4 CABLE INSTALLATION AND SPLICING ..................................................................................................................4
2.5 LIGHTNING PROTECTION .....................................................................................................................................4
3. TAKING READINGS.............................................................................................................................................6
3.1 GK-404 READOUT BOX.......................................................................................................................................6
3.2 GK-405 READOUT BOX.......................................................................................................................................7
3.2.1 Connecting Sensors with 10-pin Bulkhead Connectors Attached...............................................................7
3.2.2 Connecting Sensors with Bare Leads..........................................................................................................7
3.2.3 Operating the GK-405 ................................................................................................................................7
3.3 GK-403 READOUT BOX (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 DEFORMATION CALCULATION.............................................................................................................................9
4.2 STRAIN CALCULATION ......................................................................................................................................11
4.3 TEMPERATURE CORRECTION.............................................................................................................................11
4.4ENVIRONMENTAL FACTORS...............................................................................................................................12
5. TROUBLESHOOTING........................................................................................................................................13
APPENDIX A. SPECIFICATIONS.........................................................................................................................15
A.1MODEL 4410 VIBRATING WIRE STRANDMETER ...............................................................................................15
A.2 THERMISTOR (SEE APPENDIX BALSO)..............................................................................................................15
APPENDIX B. THERMISTOR TEMPERATURE DERIVATION.....................................................................16

FIGURES
FIGURE 1-MODEL 4410 VIBRATING WIRE STRANDMETER........................................................................................... 1
FIGURE 2-MODEL 4410 STRANDMETER INSTALLATION............................................................................................... 2
FIGURE 3-SPACER BAR POSITION................................................................................................................................. 3
FIGURE 4-LIGHTNING PROTECTION SCHEME ............................................................................................................... 5
FIGURE 5-LEMO CONNECTOR TO GK-404 ................................................................................................................... 6
FIGURE 6-LIVE READINGS –RAW READINGS............................................................................................................... 7
FIGURE 7-TYPICAL STRANDMETER CALIBRATION REPORT.........................................................................................10
TABLES
TABLE 1-ENGINEERING UNITS CONVERSION MULTIPLIERS......................................................................................... 9
TABLE 2-SAMPLE RESISTANCE ...................................................................................................................................14
TABLE 3-RESISTANCE WORK SHEET...........................................................................................................................14
TABLE 4-MODEL 4410 STRANDMETER SPECIFICATIONS.............................................................................................15
TABLE 5-THERMISTOR RESISTANCE VERSUS TEMPERATURE......................................................................................16
EQUATIONS
EQUATION 1-DIGITS CALCULATION............................................................................................................................. 9
EQUATION 2-DEFORMATION CALCULATION................................................................................................................ 9
EQUATION 3-STRAND CALCULATION IN MILLIMETERS ..............................................................................................11
EQUATION 4-STRAND CALCULATION IN INCHES.........................................................................................................11
EQUATION 5-THERMALLY CORRECTED DEFORMATION CALCULATION......................................................................11
EQUATION 6-THERMAL COEFFICIENT CALCULATION .................................................................................................12
EQUATION 7-RESISTANCE TO TEMPERATURE .............................................................................................................16

1
1. INTRODUCTION
1.1 Theory of Operation
The Geokon Vibrating Wire Strandmeter is designed to measure change in deformation in wire
strands such as those that are commonly used in tiebacks and earth anchors.
The instrument consists of a vibrating wire sensing element in series with a heat treated, 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 gage 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;
hence, the change in deformation can be determined very accurately by measuring the strain
change with the vibrating wire readout box.
Figure 1 - Model 4410 Vibrating Wire Strandmeter

2
2. INSTALLATION
2.1 Preliminary Tests
Upon receipt of the instrument, the gage should be checked for proper operation (including the
thermistor). See Section 3 for readout instructions. When the shaft is fully retracted, the vibrating
wire is slack and may give an erratic reading. This is normal. Extending the shaft very slightly
the vibrating wire is put in tension and, in position B on the readout, the gage will read around
1500 to 2000 digits.
CAUTION! Do not rotate the transducer shaft beyond 180 degrees, or extend it beyond the
range of the gage (a reading of about 8000 digits).
Checks of electrical continuity can also be made using an ohmmeter. Resistance between the
gage leads should be approximately 150Ω, ±10Ω. Remember to add cable resistance when
checking (22 AWG stranded copper leads are approximately 14.7Ω/1000' or 48.5Ω/km, multiply
by two for both directions). Between the green and white should be approximately 3000 ohms at
25 °C (see Appendix B), and between any conductor and the shield should exceed two megohms.
2.2 Strandmeter Installation
Figure 2 - Model 4410 Strandmeter Installation
Note: References to the PVC grease tube in the following instructions are for strandmeters used
on strands that are to be embedded in concrete. For strands out in the open, the grease tube may
be omitted.
Strandmeter installation is as follows:
1) Unbolt and separate the two halves of the clamps.
2) Slide the upper half of the clamp with the large hole around the strand meter so that the coil
housing sits up against the shoulder in the clamp recess.
3) Slide the PVC grease tube over the strandmeter and then the upper half of the clamp with the
small hole over the shaft end of the strandmeter.
4) Place the assembly down so that the bottoms of the two clamps sit on a flat surface.
5) Take the spacer bar and position it between the clamps. Make sure that the coil housing is
against the shoulder in the clamp, snug the two clamps up to the spacer bar.

3
6) Tighten the four 6-32 set screws holding the strandmeter to the two clamps.
Figure 3 - Spacer Bar Position
7) Remove the spacer bar and place the assembly in the correct location over the strand.
8) Tighten the lower half of the clamps onto the strand using the four cap screws.
9) Set the zero reading of the gage by completing the following:
a. Loosen the two 6-32 set screws that hold the clamp to the strandmeter shaft.
b. Insert a 10-32 screw (supplied) into the end of the shaft that comes through the clamp.
c. Connect the gage leads to the readout box (see Section 3) and switch to position 'B'.
d. While watching the reading on the readout, gently pull on the 10-32 screw until an
increasing reading is seen. Do not allow the reading to reach 8000.
e. While holding the reading between 2500-4000 (3000 is recommended), tighten the
two 6-32 set screws using the Allen wrench provided. Tighten them down hard, so
that the gage will not move.
f. Tighten the 6-32 set screws on the other clamp as well.
10)For strands that are to be embedded in concrete, fill the PVC tube with grease. A 1/4-28
threaded hole (Figure 1) is provided which will accept a standard grease fitting. Screw the
fitting into the hole, fill with grease, and then remove the fitting.
11)For embedded strandmeters, it is necessary to provide the clamps with a bond breaker. Using
the Aqua-Seal provided, place a layer over the clamp areas on both ends followed by an
overall layer of electrical tape. The purpose of this is to isolate the sensor from stresses other
than those imposed by the tendon.
12)Initial readings must be taken and carefully recorded along with the temperature at the time
of installation. These readings serve as a reference for subsequent deformation calculations.
2.3 Electrical Noise
Care should be exercised when installing instrument cables to keep them as far away as possible
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 the Geokon dataloggers and readouts should difficulties arise.

4
2.4 Cable Installation and Splicing
The cable should be routed to minimize the possibility of damage due to moving equipment,
debris or other causes. The cable can be protected by the use of flexible conduit, which can be
supplied by Geokon.
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. The interior panel of the terminal box can have built-in jacks or a single connection with a
rotary position selector switch. Contact Geokon for specific application information.
Because the vibrating wire output signal is a frequency rather than a current or voltage,
variations in cable resistance have little effect on gage readings; 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 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.
Cables may be terminated by stripping and tinning the individual conductors and then connecting
them to the patch cord of a readout box. Alternatively, a connector may be used which will plug
directly into the readout box or to a receptacle on a special patch cord.
2.5 Lightning Protection
The Model 4410 Vibrating Wire Strandmeter, unlike numerous other types of instrumentation
available from Geokon does not have any integral lightning protection components, i.e.
transzorbs or plasma surge arrestors. Usually this is not a problem however, 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 gage and possibly destroy it.
Note the following suggestions:
•If the gage is connected to a terminal box or multiplexer components such as plasma surge
arrestors (spark gaps) may be installed in the terminal box/multiplexer to provide a measure
of transient protection. Terminal boxes and multiplexers available from Geokon provide
locations for installation of these components.
•Lighting arrestor boards and enclosures are available from Geokon that install near the
instrument. The enclosure has a removable top. In the event the protection board (LAB-3) is
damaged, the user may service the components (or replace the board). A connection is made
between this enclosure and earth ground to facilitate the passing of transients away from the
gage. See Figure 4. Consult the factory for additional information on these or alternate
lightning protection schemes.

5
•Plasma surge arrestors can be epoxy potted into the gage cable close to the sensor. A ground
strap would connect the surge arrestor to earth ground, either a grounding stake or other
suitable earth ground such as perhaps the strand to which the transducer is attached.
Figure 4 - Lightning Protection Scheme
Terminal Box/Multiplexer
Instrument Cable LAB-3 Enclosure LAB-3 Board
Model 4410 Strandmeter
Strand
Ground Connections
Surface
(usually buried)

6
3. TAKING READINGS
3.1 GK-404 Readout Box
The Model GK-404 Vibrating Wire Readout is a portable, low-power, handheld unit that is
capable of running for more than 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.
Before use, attach the flying leads to the GK-404 by aligning the red circle on the silver “Lemo”
connector of the flying leads with the red line on the top of the GK-404 (Figure 5). Insert the
Lemo connector into the GK-404 until it locks into place.
Figure 5 - Lemo Connector to GK-404
Connect each of the clips on the leads to the matching colors of the sensor 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 Position: Set by the POS button, displayed as a letter 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 gage in degrees Celsius.
Use the POS button to select position Band the MODE button to select Dg (digits). (Other
functions can be selected as described in the GK-404 Manual.)
The GK-404 will continue to take measurements and display readings until the unit is turned off,
either manually, or if enabled, by the Auto-Off timer. If no reading displays or the reading is
unstable, consult Section 5 for troubleshooting suggestions.
For further information, please refer to the GK-404 manual.

7
3.2 GK-405 Readout Box
The GK-405 Vibrating Wire Readout is made up of two components: The Readout Unit,
consisting of a Windows Mobile handheld PC running the GK-405 Vibrating Wire Readout
Application; and the GK-405 Remote Module, which is housed in a weatherproof enclosure and
connects via a cable to the vibrating wire gage to be measured. The two components
communicate wirelessly using Bluetooth®, a reliable digital communications protocol. The
Readout Unit can operate from the cradle of the Remote Module, or, if more convenient, can be
removed and operated up to 20 meters from the Remote Module.
3.2.1 Connecting Sensors with 10-pin Bulkhead Connectors Attached
Align the grooves on the sensor connector (male), with the appropriate connector on the
readout (female connector labeled senor or load cell). Push the connector into place, and
then twist the outer ring of the male 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
blinking, signifying that the Remote Module is waiting to connect to the handheld unit.
Launch the GK-405 VWRA program by tapping on “Start” from the handheld PC’s main
window, then “Programs” then the GK-405 VWRA icon. After a few seconds, the blue
light on the Remote Module should stop flashing and remain lit. The Live Readings
Window will be displayed on the handheld PC. Choose display mode “B”. Figure 6
shows a typical vibrating wire output in digits and thermistor output in degrees Celsius. If
no reading displays or the reading is unstable, see Section 5 for troubleshooting
suggestions. For further information, consult the GK-405 Instruction Manual.
Figure 6 - Live Readings – Raw Readings

8
3.3 GK-403 Readout Box (Obsolete Model)
The GK-403 can store gage readings and apply calibration factors to convert readings to
engineering units. The following instructions explain taking gage measurements using Mode B.
Consult the GK-403 Instruction Manual for additional information.
3.3.1 Connecting Sensors with 10-pin Bulkhead Connectors Attached
Align the grooves on the sensor connector (male), with the appropriate connector on the
readout (female connector labeled senor or load cell). Push the connector into place, and
then twist the outer ring of the male connector until it locks into place.
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).
3.3.3 Operating the GK-403
1) Turn the display selector to position "B".
2) Turn the unit on.
3) The readout will display the vibrating wire output in digits. The last digit may change
one or two digits while reading.
4) The thermistor reading will be displayed above the gage 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
All vibrating wire transducers are equipped with a thermistor, which gives a varying resistance
output as the temperature changes. The white and green leads of the instrument cable are
normally connected to the internal thermistor.
The GK-403, GK-404, and GK-405 readout boxes will read the thermistor and display the
temperature in degrees C.
To read temperatures using an ohmmeter: Connect an ohmmeter to the green and white
thermistor leads coming from the strandmeter. Since the resistance changes with temperature are
large, the effect of cable resistance is usually insignificant. For long cables a correction can be
applied, equal to approximately 14.7 Ωper 1000 ft. / 48.5Ωper km at 20 °C. Multiply these
factors by two to account for both directions. Look up the temperature for the measured
resistance in Appendix B, Table 5.

9
4. DATA REDUCTION
4.1 Deformation Calculation
The basic units utilized by Geokon for measurement and reduction of data from Vibrating Wire
Deformation Meters are "digits". The units displayed by all Readout Boxes in position "B" are
digits. Calculation of digits is based on the following equation:
Digits =󰇡1
Period󰇢2x 10-3 or Digits=Hz2
1000
Equation 1 - Digits Calculation
To convert digits to deformation the following equation applies;
Deformation =(Current Reading - Initial Reading) ×Calibration Factor ×Conversion Factor
Or
D = (R1- R0) ×G ×F
Equation 2 - Deformation Calculation
Where;
D is the Deformation in millimeters or inches.
R1is the Current Reading.
R0is the Initial Reading usually obtained at installation.
G is the Calibration Factor, usually in terms of millimeters or inches per digit.
F is an engineering units conversion factor (optional), see Table 1.
From→
To
↓
Inches Feet Millimeters Centimeter
s
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
Meters
0.0254
0.3048
0.001
0.01
1
Table 1 - Engineering Units Conversion Multipliers
For example, the Initial Reading (R0) at installation of a strandmeter is 4783 digits. The Current
Reading (R1) is 5228. The Calibration Factor is 0.0006194 mm/digit. The deformation change is
D = (5228 −4783) ×0.0006194 = +0.2756 mm
Note that increasing readings (digits) indicate increasing extension.
A typical Calibration Sheet for a three-millimeter range strand meter is shown on the next page.

10
Figure 7 - Typical Strandmeter Calibration Report

11
4.2 Strain Calculation
The gage length of the standard strand meter is 203.2 mm, (eight inches). The strain in
microstrains μis given by the equations:
Where D is in mm: μ = (D/203.2) x 106microstrain
Equation 3 - Strand Calculation in Millimeters
Where D is in inches: μ= (D/8) x 106microstrain
Equation 4 - Strand Calculation in Inches
4.3 Temperature Correction
The Model 4410 Vibrating Wire Strandmeters have a small coefficient of thermal expansion;
therefore, in many cases correction is not necessary. However, if maximum accuracy is desired
or the temperature changes are large corrections may be applied. The temperature coefficient of
the strand to which the Strandmeter is attached should also be taken into account. By correcting
the transducer readings for temperature, changes the temperature effect on the strand can be
isolated and quantified.
The following equation applies:
Dcorrected = ((R1- R0) ×G) + ((T1- T0) ×K)
Equation 5 - Thermally Corrected Deformation Calculation
Where;
R1is the Current Reading.
R0is the Initial Reading.
G is the Calibration Factor.
T1is the Current Temperature.
T0is the Initial Temperature.
K is the Thermal Coefficient for the Transducer, (see Equation 6).
Tests have determined that the Thermal Coefficient, K, changes with the position of the
transducer shaft. Hence, the first step in the temperature correction process is determination of
the proper Thermal Coefficient based on the following equation:

12
Thermal Coefficient = (Reading in Digits ×0.000520) +3.567) ×Calibration Factor
Or
K = ((R1×0.000520) +3.567) ×G
Equation 6 - Thermal Coefficient Calculation
Where;
R1is the Current Reading.
G is the Calibration Factor supplied with the instrument.
Consider the following example using a Model 4410-5 mm Strandmeter:
R0= 4783 digits
R1= 5228 digits
T0= 15.8° C
T1= 27.2° C
G = 0.0006194 mm/digit
K = ((5228 ×0.000520) + 3.567) ×0.0006194 = 0.00389
Dcorrected = ((R1- R0) ×G) + ((T1- T0) ×K)
Dcorrected = ((5228 - 4783) ×0.0006194) + ((27.2 - 15.8) ×0.00389)
Dcorrected = (445 ×0.0006194) + 0.04435
Dcorrected = 0.2756 + 0.04435
Dcorrected = +0.3199 mm
4.4 Environmental Factors
Since the purpose of the strandmeter 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 limited to, blasting,
rainfall, tidal levels, excavation and fill levels and sequences, traffic, temperature and barometric
changes, changes in personnel, nearby construction activities, seasonal changes, etc.

13
5. TROUBLESHOOTING
Maintenance and troubleshooting of strandmeters is confined to periodic checks of cable
connections and maintenance of terminals. Once installed, the gages are usually inaccessible and
remedial action is limited. Should difficulties arise, consult the following list of problems and
possible solutions. Return any faulty gages to the factory. Gages should not be opened in the
field. For additional troubleshooting and support, contact Geokon.
Symptom: Thermistor resistance is too high:
There may be 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.
Symptom: Thermistor resistance is too low:
There may be a short. Check all connections, terminals, and plugs. If a short is located in
the cable, splice according to instructions in Section 2.4.
Water may have penetrated the interior of the transducer. There is no remedial action.
Symptom: Instrument Readings are Unstable:
Is the readout box position set correctly? If using a datalogger to record readings
automatically, are the swept frequency excitation settings correct?
Is the transducer shaft positioned outside the specified range (either extension or
retraction) of the instrument? Note that when the transducer shaft is fully retracted with the
alignment pin inside the alignment slot (as shown in Figure 1) the readings will likely be
unstable because the vibrating wire is out of its specified range.
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 install electronic filtering.
Make sure the shield drain wire is connected to ground. Connect the shield drain wire to
the readout using the blue clip. (Green for the GK-401.)
Does the readout work with another gage? If not, it may have a low battery or possibly be
malfunctioning.
Symptom: Instrument Fails to Read:
Is the cable cut or crushed? Check the resistance of the cable by connecting an ohmmeter
to the gage leads. Table 2 on the following page shows the expected resistance for the various
wire combinations; Table 3 is provided to fill in the actual resistance found. Cable resistance is
approximately 14.7 Ωper 1000' of 22 AWG wire. (Multiply this factor by two to account for
both directions.)
If the resistance is very high or infinite (megohms), the cable is probably broken or cut. If the
resistance is very low (<20Ω), the gage conductors may be shorted. If a cut or a short is located
in the cable, splice according to the instructions in Section 2.4.
Does the readout or datalogger work with another gage? If not, it may have a low battery
or possibly be malfunctioning.

14
Vibrating Wire Sensor Lead Grid - SAMPLE VALUES
Red
Black
White
Green
Shield
Red N/A
≅150Ω
infinite infinite infinite
Black
≅150Ω
N/A 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 2 - Sample Resistance
Vibrating Wire Sensor Lead Grid - SENSOR NAME/## :
Red Black White Green Shield
Red
Black
White
Green
Shield
Table 3 - Resistance Work Sheet