Geokon 6160, 6161 Installation Manual

Installation Manual

Model 6160/6161

MEMS Tilt Sensor

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

omissions or misinterpretation. The information herein is subject to change without notification.

Copyright © 2006-2019 by Geokon

(Doc Rev R, 01/09/2019)

®

assumes no responsibility for errors,

®

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 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 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 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.

TABLE of CONTENTS

1. INTRODUCTION ................................................................................................................................................... 1

2. INSTALLATION .................................................................................................................................................... 3

2.1 PRELIMINARY TESTS............................................................................................................................................ 3

2.2 INSTALLING THE MOUNTING BRACKETS.............................................................................................................. 3

2.2.1 Mounting with a Drop-in Anchor ................................................................................................................ 4

2.2.2 Mounting with an Anchor Rod .................................................................................................................... 5

2.3 SENSOR INSTALLATION........................................................................................................................................ 6

2.3.1 Installing Uniaxial Tiltmeters ..................................................................................................................... 6

2.3.2 Installing Biaxial Tiltmeters ........................................................................................................................ 6

2.4 SPLICING AND JUNCTION BOXES.......................................................................................................................... 7

2.5 LIGHTNING PROTECTION ..................................................................................................................................... 8

3. TAKING READINGS ............................................................................................................................................. 9

3.1 DATALOGGERS .................................................................................................................................................... 9

3.2 RB-500 READOUT BOX ....................................................................................................................................... 9

3.3 MEASURING TEMPERATURE ................................................................................................................................ 9

4. DATA REDUCTION ............................................................................................................................................ 10

4.1 TILT CALCULATION ........................................................................................................................................... 10

4.2 TEMPERATURE CORRECTION ............................................................................................................................. 10

4.3 ENVIRONMENTAL FACTORS ............................................................................................................................... 11

5. TROUBLESHOOTING ........................................................................................................................................ 12

APPENDIX A. SPECIFICATIONS ......................................................................................................................... 13

A.1 MEMS TILT SENSOR ........................................................................................................................................ 13

A.2 THERMISTOR ..................................................................................................................................................... 13

APPENDIX B. THERMISTOR TEMPERATURE DERIVATION ..................................................................... 14

APPENDIX C. SAMPLE CALIBRATION REPORT ........................................................................................... 15

APPENDIX D. WIRING CODE .............................................................................................................................. 16

APPENDIX E. 6160 STANDARD ADDRESSABLE SYSTEMS .......................................................................... 17

APPENDIX F. PROGRAMMING THE MEMS TILTMETER WITH CRBASIC ............................................ 19

APPENDIX G. PROGRAMMING THE ADDRESSABLE MEMS TILTMETER WITH CRBASIC ............. 20

FIGURES

IGURE 1 - MODEL 6160 MEMS TILT SENSOR .............................................................................................................. 1

F

FIGURE 2 - MOUNTING BRACKET FOR THE MODEL 6160 TILT SENSOR ......................................................................... 1

FIGURE 3 - MODEL 6161A TILT SENSOR ....................................................................................................................... 2

FIGURE 4 - MODEL 6161B TILT SENSOR ........................................................................................................................ 2

FIGURE 5 - TILTMETER MOUNTING BRACKETS .............................................................................................................. 3

FIGURE 6 - DROP-IN ANCHOR INSTALLATION (BIAXIAL MOUNTING BRACKET SHOWN) ............................................... 4

FIGURE 7 - ANCHOR ROD (UNIAXIAL MOUNTING BRACKET SHOWN) ........................................................................... 5

FIGURE 8 - UNIAXIAL INSTALLATION ............................................................................................................................ 6

FIGURE 9 - BIAXIAL INSTALLATION ............................................................................................................................... 7

FIGURE 10 - LIGHTNING PROTECTION SCHEME ............................................................................................................. 8

FIGURE 11 - SAMPLE MODEL 6160 CALIBRATION REPORT ...........................................................................................15

TABLES

ABLE 1 - MODEL 6160 AND 6161 TILT SENSOR SPECIFICATIONS ................................................................................13

T

TABLE 2 - THERMISTOR RESISTANCE VERSUS TEMPERATURE .....................................................................................14

TABLE 3 - CABLE 03-250V0 WIRING............................................................................................................................16

TABLE 4 - CABLE 06-312V0 WIRING............................................................................................................................16

TABLE 5 - ADDRESSABLE MEMS (LOGIC LEVEL STYLE) WIR ING ...............................................................................17

TABLE 6 - THERMISTOR BRIDGE CIRCUIT .....................................................................................................................18

EQUATIONS

QUATION 1 - INCLINATION VERSUS VOLTS ................................................................................................................10

E

EQUATION 2 - TILT VERSUS VOLTS ..............................................................................................................................10

EQUATION 3 - TILT VERSUS VOLTS CORRECTED FOR TEMPERATURE ..........................................................................10

EQUATION 4 - CONVERT THERMISTOR RESISTANCE TO TEMPERATURE .......................................................................14

1

1. INTRODUCTION

The Geokon Model 6160 MEMS Tilt Sensor is designed for permanent long term monitoring of
changes in tilt of structures such as dams, embankments, foundation walls, retaining walls,
buildings, and the like. There are two main types of Tilt Sensors: The Model 6160 is an adaption
of the tiltmeter used in Model 6150 In-Place Inclinometer, and the 6161 utilizes the same MEMS
sensors inside a Nema 4 enclosure. Examples of each type are shown in the Figures below. Each
style of housing contains either one or two Micro-Electro-Mechanical Systems (MEMS) sensors
oriented at 90 degrees to measure biaxial tilts. All types include a thermistor for measuring
temperatures.

They are designed to be attached to the structure so that they can sense and measure any tilting of
the structure in uniaxial or biaxial directions. Angular changes of as little as two arc seconds can
be detected.

Figure 1 - Model 6160 MEMS Tilt Sensor

Figure 2 - Mounting Bracket for the Model 6160 Tilt Sensor

2

Figure 3 - Model 6161A Tilt Sensor

Figure 4 - Model 6161B Tilt Sensor

3

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 output voltage and
inclination. The tilt sensor electrical leads are connected to a Datalogger or the RB-500 readout
box (see Section 3 for readout instructions) and the current reading compared to the calibration
readings. Carefully hold the sensor in an approximately vertical position and observe the reading.
The sensor must be held in a steady position. The readings should be close to the factory vertical
reading. The temperature indicated by the thermistor should be close to ambient.

Checks of electrical continuity can also be made using an ohmmeter. Resistance between any
conductor and the shield or the case should exceed two megohms.

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 5 - 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. See Section 2.2.1 for instructions using a drop-in anchors, and Section 2.2.2 for
an anchor rods.

4

Top View

Flat Washer

2" 3/8-16 Anchor Rod

Flat Washers

Lock Washer

3/8-16 Nuts

Wall

3/8" Drop-In Anchor

Setting Pin

2.2.1 Mounting with a Drop-in Anchor

1) Mark the location where the bracket will be installed.

2) Using a hammer drill, drill a half inch (12 mm) hole approximately 1.5" (37 mm)

deep. Clean the hole thoroughly, blowing out with compressed air if possible.

3) Insert the 3/8" drop-in anchor with setting pin into the hole. The threaded end should

be closest to the opening.

4) Insert the provided setting tool, small end first, into the anchor. Expand the anchor by

hitting the large end of the setting tool with several sharp hammer blows.

5) Thread the supplied 3/8-16 anchor rod into the anchor.

6) Attach the mounting bracket to the bolt using the supplied hardware, as illustrated in

Figure 6.

7) Use a leveling device to align the bracket vertically to the wall.

Figure 6 - Drop-in Anchor Installation (Biaxial Mounting Bracket Shown)

5

Top View

Flat Washer

4" 1/2-13 Anchor Rod

Epoxy or Grout

Flats to Prevent Bolt Twisting

Flat Washers

Lock Washer

1/2-13 Nuts

Wall

2.2.2 Mounting with an Anchor Rod

1) Mark the location where the bracket will be installed.

2) Using a hammer drill, drill a half inch (12 mm) hole approximately four inches (100

mm) deep.

3) Clean the hole thoroughly, blowing out with compressed air if possible.

4) Mix the grout or epoxy and fill the hole.

5) Push the 1/2-13 threaded anchor rod into the hole. (Use a hammer if necessary to get

the anchor to reach the bottom.)

6) Let the anchor rod set before continuing the installation.

7) After setting, attach the mounting bracket to the bolt using the supplied hardware as

illustrated in Figure 7.

8) Use a bubble level or other leveling device to align the bracket vertically to the wall.

Figure 7 - Anchor Rod (Uniaxial Mounting Bracket Shown)

6

Top View

Tilt

-

+

Instrument Cable

(Four conductor, 22 AWG)

10-32 Cap Screws

10-32 Nuts

Wall

Mounting Bracket

Tiltmeter Mounting Flange

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. Do not tighten the cap screws yet. Attach a portable

readout such as the GK-404 or GK-405 (see Section 3 for readout instructions) and
observe the reading. Adjust the sensor in the slot of the mounting bracket while observing
the readout until the tiltmeter reads within ±50 digits of the zero reading as shown on the
calibration report supplied with the sensor. (See Appendix C for a sample calibration
report.) When the desired reading is reached, tighten the cap screws to secure the
tiltmeter in place. Check the reading again after tightening to make sure it still reads
within ±50 digits of the zero reading. Figure 8 shows the completed installation.

If the tiltmeter is installed in an exposed location in a construction area, and/or if the
installation is in direct sunlight, it should be covered with a protective enclosure and/or
insulation.

Figure 8 - Uniaxial Installation

2.3.2 Installing Biaxial Tiltmeters

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. Do not tighten the cap screws yet. Attach a portable

readout such as the GK-404 or GK-405 (see Section 3 for readout instructions) and
observe the reading. Adjust each sensor in their slots of the mounting bracket while
observing the readout until the tiltmeter reads within ±50 digits of the zero reading as
shown on the calibration report supplied with each sensor. (See Appendix C

7

Top View

Tilt

-

+

Wall

Tilt

-

+

10-32 Nuts

10-32 Cap Screws

Mounting Bracket

Tiltmeter Mounting Flange

for a sample calibration report.) When the desired reading is reached, tighten the cap
screws to secure the tiltmeter in place. Check the reading again after tightening to make
sure it still reads within ±50 digits of the zero reading. Figure 9 shows the completed
installation.

If the tiltmeters are installed in an exposed location in a construction area, and/or if the
installation is in direct sunlight, it should be covered with a protective enclosure and/or
insulation.

2.4 Splicing and Junction Boxes

For manual readout using a RB-500 readout box, cables from the individual sensors are
connected to a switchbox using the wiring code shown in Appendix D. If a Datalogger is used
the cables are connected directly to the Multiplexer using the same wiring code.

The cable used for making splices should be a high quality twisted pair type with 100% shielding
(with integral shield drain wire). When splicing, it is very important that the shield drain wires be
spliced together. Splice kits recommended by Geokon (e.g., 3M Scotchcast, model 82-A1)
incorporate casts placed around the splice 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.

Figure 9 - Biaxial Installation

8

Terminal Box/Multiplexer

Instrument Cable

LAB-3 Enclosure

LAB-3 Board

Model 6350 Tiltmeter

Wall

Ground Connections

Surface

(usually buried)

2.5 Lightning Protection

The Model 6160 MEMS Tiltmeter, unlike numerous other types of instrumentation available
from Geokon, does not have any integral lightning protection components, e.g., transzorbs or
plasma surge arrestors. Usually this is not a problem. However, if the instrument cable is
exposed, it may be advisable to install lightning protection components, as the transient could
travel down the cable to the gauge and possibly destroy it.

Note the following suggestions:

• If the tiltmeter 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.

• 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
gauge (see Figure 10). Consult the factory for additional information on these or alternate
lightning protection schemes.

• Plasma surge arrestors can be epoxy potted into the gauge 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.

Figure 10 - Lightning Protection Scheme

9

3. TAKING READINGS

3.1 Dataloggers

In most cases the 6160 and 6161 MEMS Tiltmeters will be monitored continuously and
automatically using a Datalogger. Connections to the Geokon Model 8021 Micro-1000
Datalogger, which uses a Campbell Scientific CR1000 MCU are shown in Appendix D.

3.2 RB-500 Readout Box

The RB-500 readout box is designed to take readings for manually transcribing into a field book;
it has no storage capabilities. This method is useful for reading systems that do not require
continuous monitoring. The RB-500 readout box is also useful during initial installations and for
setting up Datalogger systems.

3.3 Measuring Temperature

Although the temperature dependence of the MEMS tiltmeter is tiny, and usually does not
require compensation, it sometimes happens that temperature effects can cause real changes of
tilt; therefore each MEMS tilt sensor is equipped with a thermistor for reading temperature. This
enables temperature-induced changes in tilt to be distinguished from tilts due to other sources.
The RB-500 will not read temperatures a separate digital ohmmeter is required. (The temperature
may also be read by a Geokon model GK-404.)

The thermistor gives a varying resistance output as the temperature changes. See the wiring
diagram in Appendix D for the wiring code. Appendix B shows the conversion of resistance to
temperature.

The above remarks apply mainly to structures exposed to sunlight: in these situations it is not
uncommon for the structure to expand and contract differentially during the course of the day.
For landslide applications where the MEMS sensors are buried in the ground, temperature
variations are very small or nonexistent and ground movements are unaffected by temperatures.
In these situations, it is not necessary to measure temperatures.

10

4. DATA REDUCTION

4.1 Tilt Calculation

The output of the MEMS Sensor is proportional to the sine of the angle of inclination from the
vertical. For the ±15-degree sensor the FS output is approximately ±4 volts. The reading (R) in
volts displayed on the RB-500 readout box, and the inclination (θ) is given by the equation:

θ =(R1-R

) G degrees

zero

Equation 1 - Inclination Versus Volts

Where;
R is the current reading in volts
R

is the reading at θ =zero

zero

G is the Gauge Factor shown on the calibration report for the Model 6160 tiltmeter.

For measurements of tilt, i.e., changes of inclination, where R0 is the initial reading and R1 is a
subsequent reading, the small zero reading, R

at zero inclination cancels out so that:

zero

Calculated Tilt = G(R1-R0)

Equation 2 - Tilt Versus Volts

4.2 Temperature Correction

The Model 6160 MEMS Tiltmeter has very small temperature sensitivity equal to +1 arc second
per degree centigrade rise. The tilt corrected for temperature is:

Tilt = G(R

– R0) degrees

1corr

Equation 3 - Tilt Versus Volts Corrected for Temperature

Where;
R

= R1 – 0.0003 (T1-T0)

1corr

The structure being monitored usually is affected by temperature to some degree. An important
point to note is that sudden changes in temperature will cause both the structure and the Tiltmeter
to undergo transitory physical changes, which will show up in the readings. The gauge
temperature should always be recorded, and efforts should be made to obtain readings when the
instrument and structure are at thermal equilibrium. The best time for this tends to be in the late
evening or early morning hours. For best results, the tiltmeter should be shielded from direct

sunlight.

4.3 Environmental Factors

Since the purpose of the inclinometer installation is to monitor site conditions, factors that may
affect these conditions should 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 or reservoir levels, excavation and fill levels and sequences, traffic, temperature and
barometric changes, changes in personnel, nearby construction activities, seasonal changes, etc.

11

12

5. TROUBLESHOOTING

Maintenance and troubleshooting of the MEMS sensors used in the Model 6160 and 6161
Tiltmeters are confined to periodic checks of cable connections. The sensors are sealed and there
are no user serviceable parts.

Consult the following list of problems and possible solutions should difficulties arise. Consult
the factory for additional troubleshooting help.

Symptom: Tilt Sensor Readings are Unstable

 Is there a source of electrical noise nearby? Most probable sources of electrical noise are

motors, generators, and antennas. Make sure the shield drain wire is connected to ground
whether using a portable readout or datalogger.

 Does the readout work with another tilt sensor? If not, the readout may have a low battery or

be malfunctioning.

Symptom: Tilt Sensor Fails to Read

 Is the cable cut or crushed? This can be checked with an ohmmeter. The nominal resistance

of the thermistor is 3000 ohms at 25 degrees C. If the approximate temperature is known, the
resistance of the thermistor leads can be estimated and used as a cable check. Remember to
add cable resistance when checking. Resistance of 24 AWG stranded copper leads are
approximately 25.7Ω per 1000 feet or 84.5Ω per km. Multiply this factor by two to account
for both directions. If the resistance reads infinite or very high (megohms), a cut wire must be
suspected. If the resistance reads very low (<20Ω), a short in the cable is likely.

 Does the readout or datalogger work with another tilt sensor? If not, the readout or datalogger

may be malfunctioning.

Symptom: Thermistor resistance is too high.

 Is there an open circuit? Check all connections, terminals, and plugs.

Symptom: Thermistor resistance is too low.

 Is there a short? Check all connections, terminals, and plugs.
 Water may have penetrated the interior of the tilt sensor. There is no remedial action.

APPENDIX A. SPECIFICATIONS

Model:

6160

6161A

6161B

6161C

Range:

±15°

±15°

±15°

±15°

Full Scale Output:

±4 Volts

±4 Volts

±4 Volts

Digital

Frequency

Response:

±4 arc seconds

(±0.01mm/m)

±4 arc seconds

(±0.01mm/m)

±4 arc seconds

(±0.01mm/m)

±4 arc seconds

(±0.01mm/m)

±0.05mm/m

(±10 arc seconds)

±0.05mm/m

(±10 arc seconds)

±0.05mm/m

(±10 arc seconds)

±0.05mm/m

(±10 arc seconds)

Linearity: 3

±0.07%FS

±0.07%FS

±0.07%FS

±0.07%FS

Thermal Zero

Shift:

Operating

Temperature

Diameter: 32 mm

Length:187 mm

L x W x H:

140 x 140 x 91 mm

L x W x H:

220 x 120 x 91 mm

L x W x H:

220 x 120 x 91 mm

Uniaxial:

+12V (nom) @ 45mA (9V min. / 15Vmax.)

Uniaxial:

Foil shield, Polyurethane jacket, nominal OD = 7.9 mm

One twisted pair

Nominal OD = 6.3 mm

A.1 MEMS Tilt Sensor

-3db @ 8-28 Hz -3db @ 8-28 Hz -3db @ 8-28 Hz -3db @ 8-28 Hz

Resolution:1

Accuracy: 2

0.0003 volt/°C rise 0.0003 volt/°C rise 0.0003 volt/°C rise 0.0003 volt/°C rise

-20 to +80° C -20 to +80° C -20 to +80° C -20 to +80° C

Dimensions:

13

Power

Requirements:

Electrical Cable:

4

Three twisted pair (Six conductor) 24 AWG

Foil shield, Polyurethane jacket, nominal OD = 6.3 mm

Six twisted pair (12 conductor) 24 AWG

Table 1 - Model 6160 and 6161 Tilt Sensor Specifications

+12V (nom) @ 30mA (9V min. / 15Vmax.)

Biaxial:

Biaxial:

Polyurethane jacket,

(two conductor)

22 AWG

Foil shielded,

Notes:

1

Depends on readout equipment. For best results requires a 4 ½ digit digital voltmeter.

Averaging will yield resolution on the order of two arc seconds

2

Based upon the use of a second order polynomial

3

The output of the MEMS sensor is proportional to the sine of the angle of tilt

4

Voltages in excess of 18V will damage the circuitry and are to be avoided

A.2 Thermistor

(see Appendix B also)

Range: -80 to +150° C
Accuracy: ±0.5° C

14

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

T

A

B LnR

C

LnR

=

+

+

−12732

3

(

)

( )

.

APPENDIX B. THERMISTOR TEMPERATURE DERIVATION

Thermistor Type: YSI 44005, Dale #1C3001-B3, Alpha #13A3001-B3

Resistance to Temperature Equation:

Equation 4 - Convert Thermistor Resistance to Temperature

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

Table 2 - Thermistor Resistance Versus Temperature

APPENDIX C. SAMPLE CALIBRATION REPORT

15

Figure 11 - Sample Model 6160 Calibration Report

16

APPENDIX D. WIRING CODE

03-250V0

cable

Red A 12VDC A 12VDC

Red’s Black B Ground B Ground

White C A Out Diff + C A Out Diff +

White’s Black D A Out Diff - D A Out Diff -

Bare E Shield E Shield

Green J Thermistor F B Out Diff +

Green’s Black K Thermistor G B Out Diff -

Connector Pin

Designation

Uniaxial MEMS with

Thermistor

Connector Pin

Designation

Table 3 - Cable 03-250V0 Wiring

Biaxial MEMS

without Thermistor

06-312V0

Cable

Red A 12VDC

Red’s Black B Ground

White C A Out Diff +

White’s Black D A Out Diff -

Bare E Shield

Green F B Out Diff +

Green’s Black G B Out Diff -

Blue J Thermistor

Blue’s Black K Thermistor

Connector Pin

Designation

Biaxial MEMS with Thermistor

Table 4 - Cable 06-312V0 Wiring

17

APPENDIX E. 6160 STANDARD ADDRESSABLE SYSTEMS

Description:

The standard 6160 addressable system incorporates a Distributed Multiplexer Circuit Board that
allows multiple MEMS type tiltmeters, uniaxial or biaxial, to be connected as “drops” off of a single
bus.

The tiltmeter “string” is addressed via ENABLE and CLOCK signals in the same manner as the
Geokon Model 8032-16 Channel Multiplexer.

The addressable tiltmeter string is “enabled” by raising the appropriate Datalogger Control Port
to 5V. After the string has been enabled, a delay of 125 mS is required before executing the 1st of
the two clock pulses required to activate the 1st channel. Once the channel is selected, a delay of
100 mS is required for the sensor to warm up. The sensor’s A-axis is read 100 times and then the
average of these readings is stored. The sensors B-axis is then read. Finally, the sensor’s
thermistor is read through a bridge completion circuit and the temperature is calculated using a
polynomial formula. Examples of CRBASIC programming can be found in Appendix F and
AppendixG.

Wiring:

06-312V0

Cable Color

Yellow A A-axis Output Differential +

Yellow’s Black B A-axis Output Differential -

Brown C B-axis Output Differential +

Brown’s Black D B-axis Output Differential -

Red E 12VDC

Red’s Black F Ground

White G Reset

White’s Black H Ground

Green J Clock

Green’s Black K Ground

Blue L Thermistor*

Blue’s Black M Thermistor*

Connector Pin

Designation

Addressable MEMS System

(Logic Level Style)

Bare P Shield

Table 5 - Addressable MEMS (Logic Level Style) Wiring

18

*1K and 5K precision resistors are used to complete the thermistor bridge circuit:

Table 6 - Thermistor Bridge Circuit

Specifications for Addressable System (Logic Level Style) Circuit Board:

Board Dimensions: 4.5"(L) x 1.155"(W) x 0.4"(H)

Power Requirements: +12V (± 3V)
110mA (max) when active
700uA (max) standby

Operating Temperature: -20 to +70° C

Contact Resistance: 100 mΩ (typ)

Contact Breakdown Voltage: 1500 Vrms

Relay open/close time: 4mS (max)

19

APPENDIX F. PROGRAMMING THE MEMS TILTMETER WITH CRBASIC

Description:

CRBASIC is the programming Language used with Campbell Scientific CRBASIC Dataloggers.
Campbell’s LoggerNet Software is typically used when programming in CRBASIC. The MEMS
sensor should be read with the VoltDiff instruction and the output averaged 100x. (No Thermistor in
this example.)

Sample Program:

'Declare Public Variables for Reading MEMS Sensor

Public MEMS_1
Public MEMS_2
Public MEMS_3
Public MEMS_Output 'Output of the MEMS Sensor

'Store MEMS Output every 2 minutes

DataTable (MEMS_EXAMPLE,1,-1)
Sample (1,MEMS_Output,IEEE4)
EndTable

BeginProg

'2 min scan interval

Scan (2,min,0,0)

'Read MEMS Sensor on Differential Channel 1 and average 100x Readings

Delay(0,100,mSec)
MEMS_3 = 0
For MEMS_1 = 1 To 100
VoltDiff (MEMS_2,1,mV5000,1,False,0,250,0.001,0)
MEMS_3 = MEMS_3 + MEMS_2
Next
MEMS_Output = MEMS_3 / 100

CallTable MEMS_EXAMPLE
NextScan
EndProg

20

APPENDIX G. PROGRAMMING THE ADDRESSABLE MEMS TILTMETER WITH CRBASIC

Description:

CRBASIC is the programming Language used with Campbell Scientific CRBASIC Dataloggers.
Campbell’s Loggernet Software is typically used when programming in CRBASIC. The MEMS
sensor should be read with the VoltDiff instruction and the output averaged 100x.

Sample Program:

‘The following sample program reads 20 addressable Bi-Axial MEMS Gauges and
Thermistors. The A-Axis is read on Differential Channel 1, the B-Axis is read on Differential
Channel 2 and the Thermistors are read with Single Ended Channel 5 and the bridge excited
with EX1. The string is enabled with Control Port 1 and clocked with control port 8.

'Declare Public Variables for Reading MEMS Sensor and Thermistor

Public MEMS_1
Public MEMS_2
Public MEMS_3
Public THERM_1
Public THERM_2
Public THERM_3
Public Channel 'Counter
Public Reading_A 'Output of the A Axis
Public Reading_B 'Output of the B Axis
Public Reading_THERM 'Output of Thermistor

'Store MEMS Output every 5 minutes

DataTable (MEMS_EXAMPLE,1,-1)
Sample (1,Reading_A,IEEE4)
Sample (1,Reading_B,IEEE4)
Sample (1,Reading_THERM,IEEE4)
EndTable

BeginProg

'5 min scan interval

Scan (5,min,0,0)

'enable String using C1
PortSet(1,1)

'Delay
Delay(0,125,MSEC)

'counter for number of sensors
For Channel = 1 To 20

'1st clock using C8
PortSet(8,1)
Delay(0,10,MSEC)
PortSet(8,0)
Delay(0,10,MSEC)

'Delay
Delay(0,100,mSec)

'Read the A-axis

'Reset the temporary storage location

MEMS_3 = 0

'counter

For MEMS_1 = 1 To 100

'differential voltage measurement on DIFF1

VoltDiff (MEMS_2,1,mV5000,1,False,0,1000,0.001,0)

'Sum the readings
MEMS_3 = MEMS_3 + MEMS_2

'Increment To 100
Next

'Calculate the Average reading value

Reading_A = MEMS_3 / 100

'Read the B-axis

'Reset the temporary storage location

MEMS_3 = 0

'counter
For MEMS_1 = 1 To 100

'differential voltage measurement on DIFF2

VoltDiff (MEMS_2,1,mV5000,2,False,0,1000,0.001,0)

'Sum the readings
MEMS_3 = MEMS_3 + MEMS_2

'Increment To 100
Next

21

22

'Calculate the Average reading value
Reading_B = MEMS_3 / 100

'Delay
Delay(0,100,msec)

'Read the thermistor

'half bridge measurement - SE5 AND EX1
BrHalf(THERM_1,1,mV2500,5,VX1,1,2500,0,1000,250,2.5,0.0)

'Calculate the temperature

THERM_2 = THERM_1 / 5000

THERM_3 = (2.5 - (THERM_2*1000) - THERM_1)/THERM_2

Reading_THERM = 1/(.0014051 + (.0002369*LOG(THERM_3)) +
(.0000001019*(LOG(THERM_3)^3))) - 273.2

'2nd clock using C8
PortSet(8,1)
Delay(0,10,MSEC)
PortSet(8,0)
Delay(0,10,MSEC)

'Next sensor

Next

'Disable String
PortSet(1,0)

CallTable MEMS_EXAMPLE
NextScan
EndProg