HBM FS65 Installation Manual

Installation Guide

English

FS65

Accelerometer

Hottinger Baldwin Messtechnik GmbH
Im Tiefen See 45
D-64239 Darmstadt
Tel. [phone]
Fax [phone]
[e-mail]
www.hbm.com

HBM FiberSensing, S.A.
Optical Business
Rua Vasconcelos Costa, 277
4470-640 Maia
Portugal
Tel. [phone]
Fax [phone]
[e-mail]
www.hbm.com/fs

Mat.: 7-2002.4265
DVS: A4265-2.3 HBM: public

05.2015

Sensor Design Version: v1.0

E Hottinger Baldwin Messtechnik GmbH.

Subject to modifications.
All product descriptions are for general information only.
They are not to be understood as a guarantee of quality or
durability.

English

1 Technical Details 4.........................................

1.1 General Information 4........................................

1.1.1 Overview 4.................................................

1.1.2 Characteristics 4.............................................

1.1.3 Applications 5...............................................

1.1.4 Quality 6...................................................

1.1.5 Accessories 6...............................................

1.2 General Specifications 7......................................

2 Sensor Installation 8........................................

2.1 Accelerometer 8.............................................

2.1.1 List of Materials 8............................................

2.1.2 Placing the Sensor 9.........................................

2.1.3 Fixing the Sensor 10..........................................

2.1.4 Protecting the Sensor 10.......................................

2.2 Bi or Triaxial Accelerometer 11.................................

2.2.1 List of Materials 11............................................

2.2.2 Assembling the Sensors 12....................................

2.2.3 Fixing the Assembly 20........................................

2.2.4 Protecting the Sensors 20......................................

3 Sensor Configuration 22.....................................

3.1 Sensor Calibration Sheet 22....................................

3.1.1 General nformation 23.........................................

3.1.2 Calibration Data 23...........................................

3.1.3 Acceleration Computation 23...................................

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Technical Details

1 Technical Details

1.1 General Information

This installation guide applies to the following products:

Part Number Description

K-FS65-30-11-302 FS65 - Accelerometer • Outdoor • FC/APC

K-FS65-30-13-302 FS65 - Accelerometer • Outdoor • SC/APC

K-FS65-30-10-302 FS65 - Accelerometer • Outdoor • NC

1.1.1 Overview

The FS65 - Accelerometer is a Fiber Bragg Grating
(FBG) based sensor, suitable for a large range of appli
cations where low frequency and small amplitude vibra
tions are present.

1.1.2 Characteristics

: Robustness

Long-term reliability ensured by innovative sensor
design, careful selection of materials and IP68 packag
ing.

: Completely passive

Inherent immunity to all electromagnetic effects (EMI,
RFI, sparks, etc.) and safe operation in hazardous envi
ronments.

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Technical Details

: High multiplexing capability

Connection of a large number of sensors to a single opti
cal fiber, reducing network and installation complexity.

: Remote sensing

Large distance between sensors and interrogator (sev
eral kilometers).

: Compatible with most interrogators

Provided with calibration sheet, allowing easy and accu
rate configuration.

: Self-referenced

Based on the measurement of an absolute parameter ­the Bragg wavelength - independent of power fluctua
tions.

1.1.3 Applications

HBM FiberSensing accelerometer can be used in a large
range of monitoring applications, including measuring
ambient induced vibration of civil structures.

: Civil Engineering
: Energy
: R&D

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Technical Details

1.1.4 Quality

All HBM FiberSensing's processes are strictly controlled
from development to production. Each product is sub
jected to high standard performance and endurance
tests, individually calibrated and checked before ship
ping.

HBM FiberSensing, S.A. concentrates all optical sensing
activity of HBM and is an ISO 9001:2008 certified com
pany.

1.1.5 Accessories

The implementation of complex sensing networks in large
structures is made simpler with HBM FiberSensing
accessories. These include cables especially designed to
resist harsh environments as in civil engineering, not only
during construction, but also during the lifetime of the
structure (humidity, corrosion, etc.).

HBM FiberSensing also provides accessories for com
pact in series mounting of two or three accelerometers in
transversal directions, allowing the simultaneous mea
surement of vibration along multiple axis.

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1.2 General Specifications

Sensor

Sensitivity

Measurement range ±10 g

Frequency range 0 to 50 Hz

Resonance frequency

Flatness < 2%

Resolution

Maximum calib. error ±0.1 g @ 40 Hz

Transverse sensitivity < 0.1%

Optical

Central wavelength 1500 to 1600 nm

Spectral width (FWHM) < 0.2 nm

Reflectivity > 65%

Side lobe suppression > 10 dB

Inputs / Outputs

Cable type Ø 3 mm outdoor (armor)

Cable length 2 m each side (±5 cm)

Connectors FC/APC

Environmental

Operation temperature -20 to 80 ºC

Protection class IP68

Mechanical

Materials Aluminum

Dimensions 73 x Ø 53 mm

Weight 250 g

1)

Typical values

2)

For 1 pm resolution in wavelength measurement

1)

1)

2)

75 pm/g @ 40 Hz

430 Hz

12.5 μg/ǠHz

SC/APC
NC (No Connectors)

Technical Details

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Sensor Installation

2 Sensor Installation

2.1 Accelerometer

2.1.1 List of Materials

Included Material

Accelerometer

List of Needed Equipment

The needed tools to install the FS65 - Accelerometer
depend on the structure the sensor is to be installed on.
In many cases, mounting parts may need to be designed
in order to adapt the sensor to the spot where it is going
to be installed.

The installation solution should be carefully designed in
order to meet the sensor measuring direction and the
structure characteristics.

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Sensor Installation

2.1.2 Placing the Sensor

The FS65 - Accelerometers can be placed headed up,
headed down or towards the side (Fig. 2.1).

Fig. 2.1

Information

This will only alter the sensor's DC output. Dynamically, it
will still have the same behavior.

Its position must be set according to its measuring direc
tion.

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Sensor Installation

measuring

direction

Fig. 2.2

2.1.3 Fixing the Sensor

The Accelerometer has a M5 hole on its basis to be
screwed to the surface.

2.1.4 Protecting the Sensor

Accelerometer is IP68 rated, meaning that no protection
is needed. Nevertheless, it can be protected with a box
or other protection methods.

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Sensor Installation

2.2 Bi or Triaxial Accelerometer

2.2.1 List of Materials

Included Material

S Accelerometers

S Mounting Plate:

- 1x Plate

- 1x Positioning Block

- 4x Cable Guide

- 8x M3x6

- 2x M5x8

- 4x M5x12

- 4x M6x20

S Protection Cover (optional):

- 1x Cover

- 8x M6x20

List of Needed Equipment

The needed tools to install the FS65 - Accelerometer
depend on the structure the sensor will be installed. In
many cases, mounting parts may need to be designed in
order to adapt the sensor to the spot where it is going to
be installed.

The installation solution should be carefully designed in
order to meet the sensor measuring direction and the
structure characteristics.

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Sensor Installation

2.2.2 Assembling the Sensors

The Bi or Triaxial Accelerometer is assembled on a
mounting base using two or three accelerometers.

Its position must be set according to its measuring direc
tion. On Fig. 2.3 an example of the possible two measur
ing directions is presented and on Fig. 2.4 a Triaxial
assembly is presented.

measuring

directions

Fig. 2.3

measuring

directions

Fig. 2.4

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Sensor Installation

Preparing the Mounting Plate

Mechanical parts of the mounting plate are delivered
separately.

Start by screwing the position block to the mounting plate
using 3 of the provided M5x12 screws. These screws
should be threaded from the backside as shown on
Fig. 2.5.

Mounting plate

M5x12

Fig. 2.5

Position block

Fig. 2.6

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Sensor Installation

Fixing the Sensors

On the horizontal axis, use the provided M5x8 screws to
fix the accelerometer to the positioning block.

Ensure that the fibers are oriented at approximately 30º,
with the fibers that will be exiting the protection cover at
the lower position (see Fig. 2.7 and Fig. 2.8).

M5x8

Fig. 2.7

Approx. 30°

Fig. 2.8

Fig. 2.9

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Sensor Installation

For the vertical axis sensor, use the remaining M5x12
screw.

Place the vertical sensor with the fibers oriented at 45º
(Fig. 2.12).

M5x12

Fig. 2.10

Fig. 2.11

45°

Fig. 2.12

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Sensor Installation

Arranging Cables

Use the provided Cable Guides (Fig. 2.13) and M3x6
screws to place and fix the cable guides on the mounting
plate (Fig. 2.14).

Cable Guide

M3x6

Fig. 2.13

Fig. 2.14

Considering the triaxial configuration and the defined
directions as represented on Fig. 2.15, sensor connec
tion should be performed as on Fig. 2.16:

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Sensor Installation

A

B

y

Fig. 2.15

A

z

x

AB

B

A

Sensor x

B

A

Sensor z

B

A

Sensor y

B

Fig. 2.16

Standard Accelerometers are delivered with 2 m length
cables on each side. This is not an optimized length for
the Bi or Triaxial configuration, but connections can be
performed. Fig. 2.17 shows an assembly of sensors with

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Sensor Installation

the standard cable lengths. In Fig. 2.18, an assembly of
sensors with an optimized cable length is presented.

Fig. 2.17

Fig. 2.18

Start by taking the cable B (Fig. 2.15) of the sensor on
the x axis and place it around the assembly as on
Fig. 2.19.

Then, take cable A of the sensor on the z axis and place
it around the assembly as on Fig. 2.20. Use an Optical
Adapter and attach both connectors.

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Sensor Installation

Ç

Ç

Fig. 2.19

Fig. 2.21

Fig. 2.20

Fig. 2.22

Proceed in a similar way with cable B of the z axis
accelerometer (Fig. 2.21) and cable A of the y axis
accelerometer (Fig. 2.22). Use clumps to fix cabling and
connections.

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Sensor Installation

2.2.3 Fixing the Assembly

The Bi or Triaxial assembly is now ready to be fixed to
the structure. The mounting base has 4 M6 holes for that
purpose. Four M6x20 screws are provided, but these can
be or not be suited for fixing the base to the structure.
The fixing method should be carefully defined.

2.2.4 Protecting the Sensors

Although the accelerometer is IP68 rated, the performed
connections on the assembly are not. This means that
for outdoor usage of the assembly arranged as above
should have the connectors protected against moisture
and dust. HBM FiberSensing suggests the use of a vul
canizing tape around the connectors and adapter
(Fig. 2.23).

Fig. 2.23

For mechanical protection and external cover of the Bi or
Triaxial Assembly, HBM FiberSensing has a specially
designed cover.

It is prepared to be screwed to the surface with 8 M6x20
screws and has two holes for cable exiting.

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Fig. 2.24

Sensor Installation

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Sensor Configuration

3 Sensor Configuration

3.1 Sensor Calibration Sheet

Every HBM FiberSensing sensor is provided with a cali
bration sheet. The layout of this document is the same
for all accelerometers.

Fig. 3.1

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Sensor Configuration

3.1.1 General nformation

Number 1 in Fig. 3.1 shows the general information on
the particular sensor, such as its type, the sensor part
number, its serial number and the production tracking
number, the FBG ID.

3.1.2 Calibration Data

The most important information related to the accelerom
eter sensor – the two central wavelengths at room tem
perature and sensitivity - is shown in the Calibration Data
table (number 2 in Fig. 3.1). These values should be
used for acceleration computation.

3.1.3 Acceleration Computation

Number 3 in Fig. 3.1 exemplifies the calculations that
should be performed for wavelength measurement to
acceleration conversion. The acceleration variation of an
Accelerometer, under a reference frequency, is given by
the quotient of wavelength shift from the zero moment by
the sensor's sensitivity.

acceleration + xńS ´ acceleration

+ (WL * CWL)ńS

Fig. 3.2

Where

S x is the wavelength shift in nm

S S is the given sensitivity in nm/g

S CWL is the central wavelength of the sensor at the

zero moment in nm

S WL is the measured wavelength in nm.

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HBM Test and Measurement

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measure and predict with confidence

www.hbm.com

A4265-2.3 7-2002.4265 HBM: public