PCB Piezotronics 357B22 Installation And Operating Manual Download

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General

OPERATING GUIDE

for use with

PIEZOELECTRIC CHARGE MODE ACCELEROMETERS

SPECIFICATION SHEET, INSTALLATION DRAWING

AND CALIBRATION INFORMATION ENCLOSED

PCB ASSUMES NO RESPONSIBILITY FOR DAMAGE CAUSED TO THIS PRODUCT AS A RESULT OF

PROCEDURES THAT ARE INCONSISTENT WITH THIS OPERATING GUIDE.

1.0 INTRODUCTION

Congratulations on the purchase of a quality PCB charge
mode accelerometer.  In order to ensure the highest level
of performance for this product, it is imperative that you
properly  familiarize  yourself  with  the  correct  mounting
and  installation  techniques  before attempting to operate
this device.  If, after reading this manual, you have any
additional  questions  concerning  this  sensor  or  its
application,  feel  free  to  call  an  Application  Engineer  at
716-684-0001 or the closest PCB representative.

2.0 CHARGE MODE ACCELEROMETERS

Ceramic  and  UHT  12  shear-structured  accelerometers
offer  high  performance  for  precision  vibration
measurements  in  high-temperature  environments.    The
use  of  sensing  crystals,  operating  in  the  shear  mode,
reduces  erroneous  output  due  to  base  strain,  thermal
transients, and transverse motion.

Charge mode accelerometers output a strong, high-
impedance charge signal directly from their sensing
element.  They do not contain built-in signal
conditioning electronics; the signal is conditioned
externally by either a laboratory-style charge amplifier
or in-line charge converter prior to being analyzed by a
readout or recording device.  The absence of built-in
electronics permits operation to elevated temperatures of
500 °F (260 °C) for most ceramic crystal models and

typically 900

(482 °C) and extreme application up to

100 °F (650 °

for

UHT-12.

These  accelerometers  are  ideal  for  structural  testing,
machine  monitoring,  and  vehicular  shock  and  vibration
measurement  tasks  where  high  temperatures  preclude
the use of accelerometers with built-in microelectronics.

Enclosed is a

Specification Sheet

, which lists the

complete performance characteristics of the particular
accelerometer.

3.0 OPTIONAL FEATURES

In  addition  to  these  standard  features,  a  variety  of
options are also available.  When listed before the model
number,  the  following  prefix  letters  indicate  that  the
sensor  is  manufactured  or  supplied  with  optional
features:

option- adhesive mount;

option- electrical

ground isolation;

option- metric mounting thread;

option- positive polarity output (for use with non-
inverting, signal conditioning amplifiers); and

option-

water-resistant cable connection.

4.0 INSTALLATION OVERVIEW

When  choosing  a  mounting  method,  consider  closely
both  the  advantages  and  disadvantages  of  each
technique.    Characteristics  like  location,  ruggedness,
amplitude

range,

accessibility,

temperature,

and

portability  are  extremely  critical.    However,  the  most
important  and  often  overlooked  consideration  is  the
effect the mounting technique has on the high-frequency
performance of the accelerometer.

Shown  hereafter  are  six  possible  mounting  techniques
and  their  effects  on  the  performance  of  a  typical
piezoelectric  accelerometer.    (Note  that  not  all  of  the
mounting methods may apply to your particular sensor.)
The  mounting  configurations  and  corresponding  graph
demonstrate  how  the  high-frequency  response  of  the
accelerometer may be compromised as mass is added to
the system and/or the mounting stiffness is reduced.

Note:

The low-frequency response is unaffected by the

mounting technique. Its roll-off behavior is dependent