Geokon GK-404 User manual

Instruction Manual
Model GK-404
Vibrating Wire Readout
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 © 2003-2016 by Geokon, Inc.
(Doc Rev K, 3/15/16)

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
Page
1. INTRODUCTION...................................................................................................................................................1
2. INITIAL SETUP.....................................................................................................................................................1
2.1 ACCESSORIES .......................................................................................................................................................1
2.2 ATTACHING TO A SENSOR ....................................................................................................................................2
3. OPERATION...........................................................................................................................................................2
3.1 POS (POSITION) SWITCH ................................................................................................................................3
3.2 MODE SWITCH .................................................................................................................................................3
3.3 CFG SWITCH .....................................................................................................................................................4
3.3.1BACKLIGHT:........................................................................................................................................4
3.3.2BATTERY VOLTAGE:...........................................................................................................................4
3.3.3CONTRAST:..........................................................................................................................................4
3.3.4AUTO-OFF:..........................................................................................................................................4
3.4 DEFAULT SETTINGS .......................................................................................................................................4
4. LOW BATTERY INDICATION AND AUTO-OFF............................................................................................5
5. MAINTENANCE ....................................................................................................................................................5
5.1 BATTERY REPLACEMENT .....................................................................................................................................5
5.2 CLEANING ............................................................................................................................................................5
5.3 CALIBRATION .......................................................................................................................................................5
6. TROUBLESHOOTING..........................................................................................................................................5
6.1 UNIT WILL NOT COME ON .....................................................................................................................................5
6.2 VIBRATING WIRE GAGE MEASUREMENT SHOWS DASHES ......................................................................................5
6.3 VIBRATING WIRE GAGE READING UNSTABLE ........................................................................................................6
6.4 THERMISTOR MEASUREMENT SHOWS DASHES ......................................................................................................6
6.5 DISPLAY SHOWS WEIRD CHARACTERS .................................................................................................................6
7. LIMITS OF LIABILITY........................................................................................................................................6
APPENDIX A - SPECIFICATIONS.........................................................................................................................7
A.1 VIBRATING WIRE READOUT:...............................................................................................................................7
A.2 TEMPERATURE READOUT:...................................................................................................................................7
A.3 PHYSICAL: ...........................................................................................................................................................7
APPENDIX B - CONNECTOR PIN OUTS..............................................................................................................7
B.1 TRANSDUCER PLUG PIN OUT ...............................................................................................................................7
APPENDIX C - THERMISTOR TEMPERATURE DERIVATION.....................................................................8

FIGURES
Page
FIGURE1.......................................................................................................................................................................1
FIGURE2,FIGURE3,FIGURE4......................................................................................................................................2
FIGURE5.......................................................................................................................................................................2
TABLES
Page
TABLE1–POSITIONSPECIFICATIONS...........................................................................................................................3
TABLE2‐TRANSDUCERPLUGPINOUT........................................................................................................................7
TABLE3‐RESISTANCEVERSUSTEMPERATURE............................................................................................................8

1
1. Introduction
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.
2. Initial Setup
2.1 Accessories
The GK-404 is sold with the following accessories:
GK-404-1 flying leads
Carrying case
Nylon strap for the carrying case
Neck strap for the GK-404
Before use, attach the flying leads to the GK-404 by aligning the red circle on the silver “Lemo”
connector on the flying leads with the red line on the top of the GK-404. Insert the Lemo
connector into the GK-404 until it locks into place (Figure 1). Remove the flying leads before
storing the GK-404 in the carrying case by pulling the Lemo connector out of the unit.
Figure 1
To install the neck strap onto the GK-404, locate the plastic connector on the neck strap (Figure
2) and place the larger circular hole onto the plastic nub on the back of the GK-404, with the
bottom of the connector positioned to the right (Figure 3). Next slide the connector all the way
to the right, then twist it clockwise until the bottom of the connector is pointing down (Figure 4).
Lastly, snap together the twin connectors located at the strap ends (Figure 5).

2
Figure 2 Figure 3 Figure 4
Figure 5
To install the nylon strap onto the carrying case, clip both ends of the strap onto the plastic loops
on the sides of the case.
2.2 Attaching to a Sensor
Attach the GK-404-1 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. OPERATION
To turn the GK-404 on, press the “ON/OFF” button on the front panel of the unit. The initial
startup screen will display:
GeokonInc.
GK-404 verX.XX
After approximately 1 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, displayed as a numeric value, followed by the unit of measure (set
by the MODE button).
Temperature reading of the attached gage in degrees Celsius.

3
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. (See section 3.3.4) To turn the GK-404 off
manually, press and hold the ON/OFF button until Saving Settings is displayed then release. All
user settings are stored on shut off and will be restored the next time the GK-404 is turned on.
3.1 POS (POSITION) SWITCH
Pressing the POS button will select the proper pluck settings for the vibrating wire gage that you
want to read.
Each Position setting (A-F) has different preprogrammed parameters that are optimized for
certain instruments. Each option also has different scaling and processing characteristics. See
the table below to determine the best choice for your sensors.
POS
Use with Geokon
Model No. MODE
Calculation
T = Period (1/F) in Sec
F = Frequency in Hertz
Units
Frequency
Sweep (Hz)
A All Dg
Hz
S
F210-3
F
T
Digits
Hertz
Sec
450-6000
B 4300BX, 4400,
4500, 4600, 4700,
4800, 4900
Dg
Hz
S
F210-3
F
T
Digits
Hertz
Sec
1500-3500
C 4000 E
Hz
S
F210-34.062
F
T

Strain ()
Hertz
Sec
450-1200
D 4200 E
Hz
S
F210-33.304
F
T

Strain ()
Hertz
Sec
450-1200
E 4100 E
Hz
S
F210-30.39102
F
T

Strain ()
Hertz
Sec
1500-3500
F 4300EX Dg
Hz
S
F210-3
F
T
Digits
Hertz
Sec
2500-6000
Table 1 – Position Specifications
3.2 MODE SWITCH
Pressing the MODE button will select the format of the vibrating wire reading. The available
options are: Dg (digits), Hz (hertz), S (period) and E (microstrain). Note: Only Positions C, D
& E support the E microstrain format.

4
3.3 CFG SWITCH
Pressing the CFG button will cause the GK-404 to enter the Configuration Menu. The
LCD screen will display:
GK-404 verX.XX
Config Menu
From this menu several GK-404 operating parameters may be set. Use the POS button to
select the various parameters and the MODE button to select each parameter’s options.
Press CFG twice at any time to exit the Configuration Menu and return to the Readings
Screen.
3.3.1 BACKLIGHT:
Press MODE to turn the LCD backlight ON or OFF.
3.3.2 BATTERY VOLTAGE:
This is a bar graph display of the power remaining in the (2) 1.5V AA cells, with Ffor
FULL and Efor EMPTY. The GK-404 is capable of continuous operation for greater
than 20 hours on a fresh set of batteries.
3.3.3 CONTRAST:
Press the MODE button to adjust the contrast of the LCD display in 10% increments.
3.3.4 AUTO-OFF:
Press the MODE button to select automatic shut-off after 5 minutes, 15 minutes or 30
minutes. You may also disable the Auto-Off timer so that the GK-404 will only shut off
if the front panel ON/OFF button is pressed. The Auto-Off will only activate if no front
panel buttons are pressed for the specified amount of time. The timer will reset each time
a button is pressed. When the GK-404 does shut off, all settings are saved to internal
memory and will restore the next time the GK-404 is turned on. (Note: The above
mentioned times are approximate.)
3.4 DEFAULT SETTINGS
Factory default settings may be restored at any time by pressing and holding the CFG and
POS buttons when turning the GK-404 ON. The factory default settings are:
POS B
MODE Dg
BACKLIGHT OFF
CONTRAST 50%
POWER-OFF TIME 5 minutes

5
4. Low Battery Indication and Auto-Off
The GK-404 continuously monitors the status of the (2) 1.5V AA cells. When their combined
voltage drops to 2V, the message Batteries Low is displayed on the screen. A fresh set of 1.5V
AA batteries should be installed at this point. If the battery voltage drops to 1.8V, the message
REPLACE BATTERIES will be displayed on the screen; the GK-404 will then shut itself off.
All settings are still saved in the internal non-volatile memory.
5. Maintenance
5.1 Battery Replacement
Alkaline batteries are the best choice for use in the GK-404. A set of (2) 1.5V AA batteries are
installed in the GK-404 at the factory. To replace the batteries, use a #1 Phillips screwdriver to
remove the battery compartment cover located at the back of the readout. Install a new set of
batteries following the polarities indicated inside the battery compartment. Reinstall the battery
compartment cover.
Never use two different types of batteries or mix old batteries with new. This could cause
batteries to leak and permanently damage the readout. Although alkaline batteries are highly
recommended, carbon zinc “AA” batteries can be used.
5.2 Cleaning
A clean cloth can be used to wipe down the GK-404 Readout. No solvents should be used as
they may damage the case of the readout.
5.3 Calibration
The readout should be sent periodically (every 12 months) to the manufacturer for inspection,
cleaning, and calibration. A nominal fee will be charged for the service, but it is highly
recommended.
6. TROUBLESHOOTING
Listed below are a few commonly experienced problems and remedial action. Contact the
factory should a problem arise not explained herein.
6.1 Unit will not come on
Internal batteries are either dead or installed backwards.
6.2 Vibrating wire gage measurement shows dashes
Check Alligator Clip connections to vibrating wire gage leads. If okay, check gage with
Ohmmeter. It should read between 90 and 180 ohms. If gage resistance is okay, check Readout

6
with another gage. If it still doesn't work, consult the factory to schedule return and repair of
Readout.
6.3 Vibrating wire gage reading unstable
Improper POSition selected. Verify gage model number against the recommended setting. (See
Table 1.) If POSition setting is correct, the gage is either marginal or there may be a strong
source of electro-magnetic interference nearby.
6.4 Thermistor measurement shows dashes
Check Alligator Clip connections to Thermistor leads. If okay, check Thermistor with
Ohmmeter. It should read between 10K ohms and 2.4K ohms (0 to +30 degrees Celsius). If
Thermistor checks out okay consult factory to schedule repair of Readout. Note: Dashes will
display if no Thermistor is connected.
6.5 Display shows weird characters
Turn the GK-404 ON while pushing the CFG and POS buttons at the same time to restore the
unit to its factory default settings.
7. Limits of Liability
The GK-404 Vibrating Wire Readout has been developed specifically for use with Geokon, Inc.
vibrating wire gages and, as such, Geokon, Inc. assumes no responsibility for its use with other
systems. Every effort has been made to ensure reliable operation, but the user must be aware
that there is no warranty against uninterrupted or trouble-free operation. For the user conducting
particularly unusual or sensitive analysis, or for those not familiar with vibrating wire gage data
processing, it is recommended that the problems be double checked using another measurement
system.
Also, the readout is provided 'as is' and Geokon, Inc. assumes no responsibility as to results,
performance, or interpretation associated with the GK-404 Vibrating Wire Readout. Warranty
shall cover parts (except batteries) and labor for a period of 1 year from the date of purchase. In
addition, there is a 1-month grace period to the warranty for a total of 13 months.
We reserve the right to revise this publication and/or readout from time to time with no
obligation to notify users of these changes.
All things considered, Geokon, Inc., is not liable for any claims, injuries, or damages
caused directly or indirectly by the proper or improper use of the GK-404 Vibrating Wire
Readout, beyond the purchase price of the Readout.

7
APPENDIX A - SPECIFICATIONS
A.1 Vibrating Wire Readout:
Excitation Range: 400 Hz to 6000 Hz, 5-volt square wave
Measurement Resolution: 0.1Hz
0.1uS
0.1Digit
Measurement Accuracy: +/-0.025 % of Full Scale (6000 Hz)
A.2 Temperature Readout:
Sensor Type: Thermistor, YSI 44005, Dale #1C3001-B3, Alpha #13A3001-B3
Sensor Accuracy: 0.5Celsius
Measurement Range: 20to 50Celsius
Measurement Resolution: 0.1Celsius
Measurement Accuracy: +/- 1.0% of Full Scale
A.3 Physical:
Display: 16 Columns x 2 Lines LCD
Dimensions: 120mm (4.72") x 65mm (2.56") x 22mm (0.87")
Weight: Approx. 145 grams (5.1 ounces) with (2) “AA” alkaline batteries installed
Temperature Range: -20to +50Celsius
Battery: (2) “AA” 1.5 volt alkaline.
Operating Time: minimum 24 hours continuous at +25º Celsius
APPENDIX B - CONNECTOR PIN OUTS
B.1 Transducer Plug Pin Out
5-pin LEMO
HGG.OB.305.CLL
P
Wire
Color
Alligator Clip Boot Color
(Flying Leads) Description
1 Red Red VW Gage +
2 Black Black VW Gage -
3 White White Thermistor +
4 Green Green Thermistor -
5 Bare Blue Drain Wire
Table 2 - Transducer Plug Pin Out

8
APPENDIX C - THERMISTOR TEMPERATURE DERIVATION
Thermistor Type: YSI 44005, Dale #1C3001-B3, Alpha #13A3001-B3
Resistance to Temperature Equation:
where: T Temperature in C.
LnR Natural Log of Thermistor Resistance
A 1.4051 10-3 (coefficients calculated over the 50 to +150C. span)
B 2.369 10-4
C 1.019 10-7
Resistance versus Temperature Table:
Ohms Temp Ohms Temp Ohms Temp Ohms Temp Ohms Temp
201.1K -50 16.60K -10 2417

30 525.4

70 153.2 110
187.3K -49 15.72K -9 2317 31 507.8 71 149.0 111
174.5K -48 14.90K -8 2221 32 490.9 72 145.0 112
162.7K -47 14.12K -7 2130 33 474.7 73 141.1 113
151.7K -46 13.39K -6 2042 34 459.0 74 137.2 114
141.6K -45 12.70K -5 1959 35 444.0 75 133.6 115
132.2K -44 12.05K -4 1880 36 429.5 76 130.0 116
123.5K -43 11.44K -3 1805 37 415.6 77 126.5 117
115.4K -42 10.86K -2 1733 38 402.2 78 123.2 118
107.9K -41 10.31K -1 1664 39 389.3 79 119.9 119
101.0K -40 9796 0 1598 40 376.9 80 116.8 120
94.48K -39 9310 1 1535 41 364.9 81 113.8 121
88.46K -38 8851 2 1475 42 353.4 82 110.8 122
82.87K -37 8417 3 1418 43 342.2 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 85.7 132
44.16K -27 5177 13 965.0 53 250.9 93 83.6 133
41.56K -26 4939 14 929.6 54 243.4 94 81.6 134
39.13K -25 4714 15 895.8 55 236.2 95 79.6 135
36.86K -24 4500 16 863.3 56 229.3 96 77.6 136
34.73K -23 4297 17 832.2 57 222.6 97 75.8 137
32.74K -22 4105 18 802.3 58 216.1 98 73.9 138
30.87K -21 3922 19 773.7 59 209.8 99 72.2 139
29.13K -20 3748 20 746.3 60 203.8 100 70.4 140
27.49K -19 3583 21 719.9 61 197.9 101 68.8 141
25.95K -18 3426 22 694.7 62 192.2 102 67.1 142
24.51K -17 3277 23 670.4 63 186.8 103 65.5 143
23.16K -16 3135 24 647.1 64 181.5 104 64.0 144
21.89K -15 3000 25 624.7 65 176.4 105 62.5 145
20.70K -14 2872 26 603.3 66 171.4 106 61.1 146
19.58K -13 2750 27 582.6 67 166.7 107 59.6 147
18.52K -12 2633 28 562.8 68 162.0 108 58.3 148
17.53K -11 2523 29 543.7 69 157.6 109 56.8 149
55.6 150
Table 3 - Resistance versus Temperature
TA B LnR C LnR 


1273 2
3
()() .