Kistler 8765A250 Series User manual

Instruction
Manual
PiezoStar Shear
Triaxial IEPE
Types
8765A250...,
8766A...
ä
8766A_002-270e-01.19

Instruction
Manual
PiezoStar Shear
Triaxial IEPE
Types
8765A250...,
8766A...
ä
8766A_002-270e-01.19

Foreword
Foreword
8766A_002-270e-01.19
Thank you for choosing a Kistler quality product characterized
by technical innovation, precision and long life.
Information in this document is subject to change without notice.
Kistler reserves the right to change or improve its products and
make changes in the content without obligation to notify any
person or organization of such changes or improvements.
© 2014 ... 2019 Kistler Group. Kistler Group products are
pro-tected by various intellectual property rights. The Kistler
Group includes Kistler Hold-ing AG and all its subsidiaries in
Europe, Asia, the Americas and Australia.
Page 1

8766A_002-270e-01.19Page 2
PiezoStar Shear Triaxial IEPE Accelerometers, Type 8765A..., 8766A...
Content
1. Introduction.......................................................................................................................................4
2. Important information ......................................................................................................................5
2.1 For your safety .......................................................................................................................5
2.2 Precautions ............................................................................................................................6
2.3 Disposal of electronic equipment ...........................................................................................6
3. Product description..........................................................................................................................7
3.1 PiezoStar shear background..................................................................................................7
3.2 Low impedance (IEPE) output................................................................................................8
3.3 Accessories ............................................................................................................................9
3.3.1 Studs.......................................................................................................................10
3.3.2 Cables.....................................................................................................................11
3.3.3 Nomenclature .........................................................................................................11
4. Installation.......................................................................................................................................12
4.1 Surface preparation..............................................................................................................12
4.2 Screw and stud mounting.....................................................................................................13
4.3 Direct adhesive mounting.....................................................................................................14
4.4 Mounting with wax................................................................................................................15
4.5 Mounting with magnet ..........................................................................................................15
4.6 Summary of mounting methods ...........................................................................................17
4.7 Securing cables....................................................................................................................18
4.8 Mass loading effects.............................................................................................................19
5. Operating instructions...................................................................................................................20
5.1 Powering ..............................................................................................................................20
5.1.1 Using "Built-In" power sources................................................................................20
5.1.2 Kistler couplers .......................................................................................................21
5.1.3 The constant current power supply/coupler............................................................21
5.1.4 Sensor power-up ....................................................................................................24
5.1.5 Overload recovery ..................................................................................................24
5.1.6 Supply voltage effects.............................................................................................25
5.1.7 Driving long cables .................................................................................................25
5.1.8 Ground loops ..........................................................................................................27
5.1.9 Ground isolation......................................................................................................29
5.1.10 Frequency response limits....................................................................................29
5.1.11 Frequency response denition and standards ......................................................30
5.1.12 High Frequency limitations ...................................................................................30
5.1.13 Low Frequency limitations - accelerometer ..........................................................31
5.1.14 Low frequency limitations - coupler and read-out instrumentation .......................33

Page 38766A_002-270e-01.19
Content
Total pages: 45
6. Measurement ..................................................................................................................................34
6.1 Piezoelectric measurement concept ....................................................................................34
7. Technical data.................................................................................................................................35
8. Calibration and maintenance ........................................................................................................36
8.1 Calibration ............................................................................................................................36
8.2 Maintenance.........................................................................................................................36
9. Troubleshooting .............................................................................................................................37
10. Storage & transit considerations................................................................................................38
11. Warranty ........................................................................................................................................39
12. Declaration of conformity............................................................................................................40

8766A_002-270e-01.19
PiezoStar Shear Triaxial IEPE Accelerometers, Type 8765A..., 8766A...
Page 4
Thank you for choosing a quality product from Kistler. Please
read through this manual thoroughly to enable you to fully
exploit the various features of your product.
To the extent permitted by law Kistler accepts no liability if
this instruction manual is not followed or products other than
those listed under Accessories are used.
Performance features at a glance:
Hermetic, titanium construction
PiezoStar element with low sensitivity to temperature
IEPE, 50 g to 1,000 g ranges
Miniature, lightweight design
High operating temperature option (165 °C / 330 °F)
Mini and standard, 4 pin connector options for lower mass
and wider frequency operation
Conforming to ä
Kistler offers a wide range of products for use in measuring
technology:
Piezoelectric sensors for measuring force, torque, strain,
pressure, acceleration, shock, vibration and acoustic
emission
Strain gage sensor systems for measuring force and
torque
Piezoresistive pressure sensors and transmitters
Signal conditioners, indicators and calibrators
Electronic control and monitoring systems, as well as
software for specic measurement applications
Data transmission modules (telemetry)
Kistler also develops and produces measuring solutions
for the application elds engines, vehicles, manufacturing,
plastics and biomechanics sectors.
Our product and application brochures, in addition to our
detailed data sheets, will provide you with an overview of our
product range.
If you require additional help beyond what can be located
online or in this manual, please contact Kistler‘s extensive
support organization or visit us online at www.kistler.com.
1. Introduction

8766A_002-270e-01.19
Important Information
Page 5
2. Important information
This product has been manufactured in compliance with
current valid safety regulations. It has left the factory in a
perfect, safe condition. In order to maintain this condition and
ensure safe operation, compliance is required with the inst-
ructions and warning notes contained within this manual or
imprinted on the product itself.
Compliance with local safety regulations, which may apply
to the use of power line operated electrical and electronic
equipment, is strongly recommended.
It is essential for you to review the following information, which
is intended to ensure your personal safety when working
with the PiezoStar Shear Triaxial IEPE Accelerometers and
contribute toward a long-fault-free service life.
2.1 For your safety

8766A_002-270e-01.19
PiezoStar®Shear Triaxial IEPE Accelerometers, Type 8765A..., 8766A...
Page 6
2.3 Disposal of electronic equipment
2.2 Precautions
Compliance with the following precautionary measures is
vital to ensure safe and reliable operation:
▪ Never expose the instrument to contamination or oil mist.
▪ Never operate or store the instrument outside the specified
temperature range.
▪ Never exceed the maximum stated voltage
▪ Connect the instrument only to equipment for which it was
designed to be used.
▪ Never allow the product to drop.
▪ The environment should be as dry, clean and free from
vibrations as possible.
▪ Never operate the instrument if there are visible signs of
damage.
If there is evidence that safe operation is no longer possib-
le, the instrument must be powered off and rendered safe
against accidental start-up. Safe operation is no longer pos-
sible when the product:
▪ shows visible signs of damage
▪ is no longer operating
▪ has been subjected to prolonged storage under unsuitable
conditions
Do not discard old electronic equipment in municipal trash.
For disposal at end of life, please return this product to the
nearest authorized electronic waste disposal service or
contact your Kistler sales ofce for disposal instructions.

8766A_002-270e-01.19
Product Description
Page 7
3. Product description
3.1 PiezoStar shear background
Kistler PiezoStar Shear Triaxial IEPE accelerometers are
shear mode shock and vibration measuring instruments.
A self-generating piezoelectric sensing element is used
in conjunction with the built-in, internal circuit Piezotron
impedance converter.
As with most accelerometers, the sensitivity of this series is
expressed in terms of the ratio of the electrical output to the
applied acceleration (i.e. mV/g). Piezotron devices offer a low
impedance output voltage signal, which is proportional to the
applied acceleration. A charge amplier or special cabling is
not required and transmission over long lines is possible with
minimal noise pick-up.
A typical Kistler sensing assembly (see Fig. 1) consists
of a center post, PiezoStar element and a seismic mass
mechanically preloaded, with or without a preload bolt. Since
the unit is operated in a shear arrangement it will sense
motion perpendicular to the base. When the accelerometer
is attached to a vibrating structure, the mass exerts a
shear force on the PiezoStar. This applied force causes the
piezoelectric material to produce an electric charge. Force
= mass x’s acceleration (from Newton's second law). Since
m is the constant, the charge produced is proportional to
acceleration. This is represented by the equation:
a= F
—
m
Fig. 1: Inside view of a typical single-axis shear accelerom-
eter

8766A_002-270e-01.19
PiezoStar®Shear Triaxial IEPE Accelerometers, Type 8765A..., 8766A...
Page 8
3.2 Low impedance (IEPE) output
Contained within the accelerometer housing is a miniature
electronic circuit. This circuit converts the high impedance
charge signal generated by the piezoelectric element into a
low impedance voltage output signal. All accelerometer types
have a nominal output less than 100 ohms.
The integral impedance converter is powered by an external
power source (coupler) that uses a two-wire cable between
the accelerometer and coupler. The signal and power source
share a common line. The coupler provides a constant
current source to the accelerometer and decouples the DC
bias (see Section 5.1.3) from the measuring instrument. The
useable signal is seen as a varying voltage over an 11 VDC
(nominal) bias.
Low impedance accelerometers are ideally suited for
applications where long or moving cables are required, in
high humidity or other impure atmospheres. They eliminate
the difculties associated with a high impedance output
by providing a voltage signal with low impedance and a
high frequency response. The calibration factors for these
accelerometers are given in mV/g.
Table 1 depicts a typical low impedance measurement
system. Couplers vary considerably in appearance,
depending upon the application and the number of sensors
making up the system. It can also be directly integrated to the
data acquisition system.
The PiezoStar Shear sensing element, similar to the
K-Shear element shown in Fig. 1, offers many advantages
over previous compression mode designs. Due to its shear
construction, the accelerometer element is insensitive to
thermal transients, transverse (cross-axis) motion, and the
effects of base strain.
Kistler initially introduced this K-Shear design using a quartz
element that has become a standard with many users. Kistler
PiezoStar accelerometers utilize the same basic construction
as our K-Shear accelerometers, with the exception of one key
difference: PiezoStar accelerometers utilize a new proprietary
piezoelectric crystal, which produces higher charge output
when compared with quartz-based accelerometers, and
also offer a higher operating temperature. When mated with
internal Piezotron electronics, the accelerometer has the
additional benet of much lower temperature coefcient of
sensitivity when compared with quartz and ceramic-based
accelerometers.