You are here: User > Product Literature > User Guide > Sensor Selection
DeutschEnglish
5/21/2012

Sensor Selection

In order to achieve optimum measurement conditions the following questions should be answered:

 

  • Can you make unadulterated measurements of the vibration and derive the needed information at the selected location?
  • Does the selected location provide a short and rigid path to the vibration source?
  • Is it allowable (considering warranty restrictions) and possible in technical respects to prepare a flat, smooth, and clean surface with mounting thread for the accelerometer?
  • Can the accelerometer be mounted without altering the vibration characteristics of the test object?
  • Which environmental influences (heat, humidity, EMI, bending etc.) may occur?

 

The following table shows a summary of the most important criteria for selecting an accelerometer:

 

Criteria

Accelerometer properties

Amplitude range

Choose appropriate sensitivity and maximum acceleration,

Use seismic accelerometers for lowest vibration

 

 

Selection chart for acceleration:

<10g:

KB12VD, KS48C

 
10-200g:

KS76C.100/77C.100, KS78.100, KS901.100, KS94B.100/95B.100, KS813B, KS823B, KS943B.100, KB103SVD-100, KS74C.100, KS80D, KS81B, AC905-1A, AC906-1A, KST94C-4N/-9N

 
200-1000g:

KS76C.10/77C.10, KS78.100, KS901.10, KS91/94B.10/95B.10, 3023A1T, KS74C.10

 
1000-10000g:

KS56/KS57, KS90, iQD62.1, KS93, 3023A9

 

>10000g:

iQD62.005

Frequency range

Selection chart for the upper 3 dB frequency limit:

<0.3 kHz:

KB12VD

 

0.3-10 kHz:

KS48C, KS813B, KS823B, 3023A9, 3023A1T, KB103SVD-100, AC906-1A, KST94C-4N/-9N

 

10-15 kHz:

KS81B, AC905-1A


15-25 kHz:

KS56/KS57, KS76C.100/77C.100, KS78.10/.100, KS90, KS901.10/.100, KS93, KS943B.100, KS74C.100, KS80D

 
>25kHz:

KS76C.10/77C.10, iQD62.005/.1, KS91, KS94/95B.10, KS91, KS94/KS95B.100, KS74C.10

Weight of test object

  • Accelerometer weight <1/10 the weight of test object
  • Test method for accelerometer weight to ISO 2954:
    "Double de co-vibrating mass of the sensor by an additional mass. If the new indication shows a deviation from the original reading of more than 12%, the mass of the accelerometer is too great."
  • Choose miniature accelerometers for light test objects

 

 

Selection chart for the sensor weight:
<3gr:

KS91, KS93, KS94/95B.10, KS94/KS95B.100

 
3-20gr:

KS78.10/.100, KS90, KS901.10/.100, iQD62.005/.1, KS943B.100, 3023A9, 3023A1T

 
20-50gr:

KS56/KS57, KS76C.10/.100, KS77C.10/.100, KS74C.10/.100

 
50-100gr:

KS80D, AC905-1A

 
>100gr:

KB12VD, KS48C, KS813B, KS823B, KB103SVD-100, KS81B, AC906-1A, KST94C-4N/-9N

Temperature transients,
base strain,
magnetic fields, extreme acoustic noise

Assess influence, choose sensor acc. to characteristics,

Choose shear-type accelerometers when temperature transients and base strain may occur,

Stainless steel versions for strong magnetic fields

Humidity and dust

Industrial accelerometers with protection grade IP67

Measurement of vibration velocity and displacement

Single and double integration, below 20 Hz  use shear-type accelerometers (KS models)

Mounting

  • Quick measurements below 1 kHz with low accuracy: Use accelerometer probe
  • For temporary measurements without altering the test object: Mounting with magnetic clamp, wax or adhesives
  • Long-term measurements: Use stud mounting or insulating flange

Grounding problems, potential differences

Use insulating flanges or insulated accelerometers

Long distance between sensor and instrument

Choose IEPE accelerometers

Measurements in two or three axes

Use triaxial accelerometers or triaxial mounting cubes

    

 

Copyright (C) 2008 Metra Mess- und Frequenztechnik, edited by IDS Innomic.
Publication allowed, if we are named  as source and a short information about the publication purpose
was sent to us.