Measurement Computing 4623 Operating Manual

Operating Manual

TM TM

Model 4623 Accelerometer

Measurement Specialties, Inc.

Vibration Sensors Design Center

32 Journey, Suite 150

Aliso Viejo, CA 92656 USA

Tel: [phone]

www.meas-spec.com

[e-mail]

Measurement Specialties, Inc. www.meas-spec.com [phone]

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Operating Manual

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Warranty

Measurement Specialties, Inc. accelerometers
are warranted during a period of one year from
date of shipment to original purchaser to be free
from defects in material and workmanship. The
liability of Seller under this warranty is limited to
replacing or repairing any instrument or
component thereof which is returned by Buyer,
at his expense, during such period and which
has not been subjected to misuse, neglect,
improper installation, repair, alteration, or
accident. Seller shall have the right to final
determination as to the existence and cause of a
defect. In no event shall Seller be liable for
collateral or consequential damages. This
warrant is in lieu of any other warranty,
expressed, implied, or statutory; and no
agreement extending or modifying it will be
binding upon Seller unless in writing and signed
by a duly authorized officer.

Receiving Inspection
Every Measurement Specialties, Inc.

accelerometer is carefully inspected and is in
perfect working condition at the time of
shipment. Each accelerometer should be
checked as soon as it is received. If the unit is
damaged in any way, or fails to operate, a claim
should immediately be filed with the
transportation company.

Service Concerns

If a Measurement Specialties, Inc. instrument
requires service, first contact the nearest
Measurement Specialties, Inc. representative.
They may be able to solve the problem without
returning the unit to the factory. If it is
determined that factory service is required, call
Customer Service at the regional headquarters
for an RMA number before return.

Returns

All units being returned to the factory require an
RMA (Return Material Authorization) number
before they will be accepted. This number may

be obtained by calling Customer Service at the
regional headquarters with the following
information; model number(s), quantity, serial
number(s), and symptoms of the problem, if
being returned for service. You must include the
original purchase order number if under
warranty.

Recalibration Services

The Vibration Sensors Design Center and its
two manufacturing facilities in China and France
offer factory re-calibration services for
Piezoresistive, Piezoelectric and Integrated
Electronics Piezoelectric (IEPE, ISOTRON, ICP,
etc.) accelerometers. NIST (US), DKD
(Germany), COFRAC (France) traceable
calibration services on sensitivity at 100 Hz (102
or 120 Hz in Europe) and full frequency sweeps
are offered. Contact the regional headquarters
for pricing information.

Inquiries

Address all inquiries on operation or applications
to your nearest Sales Representative, or to the
Vibration Applications Support as follows:

Global Headquarters

1000 Lucas Way
Hampton, VA 23666, USA
Tel: [phone]

Vibration Sensors Design Center

32 Journey, Suite 150
Aliso Viejo, CA 92656, USA
Tel: [phone]

European Headquarters

Impasse Jeanne BENOZZI
CS 83 163, 31027 Toulouse Cedex 3, France
Tel: [phone]

Asian Headquarters

Measurement Specialties (China), Ltd.
No. 26 Langshan Road
Shenzhen High-Tech Park (North)
Nanshan District, Shenzhen 518057, China
Tel: [phone]

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Operating Manual

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Mounting screws
Torque to 3 lb-in (0.3 Nm)

Description

The Model 4623 is a signal conditioned and temperature compensated MEMS accelerometer offering
high sensitivity in ranges from ±2g to ±100g. The DC response accelerometer offers outstanding
performance over a wide operating temperature range and incorporates an EMI/EMC protection circuitry
for harsh installations. The output is filtered and signal conditioned to provide a low noise amplified signal
with exceptional resolution. The Model 4623 accelerometer incorporates a rugged strain relief for
demanding applications and is packaged in an anodized aluminum housing.

Installation

The model 4623 accelerometer is designed to be screw mounted but can also be adhesively mounted if
the installation does not allow for screw mounting.

Screw Mounting

For screw mounting of accelerometers the following guidelines should be followed:

 The mounting surface should be clean and free of any residue or foreign material.
 The mounting surface should be smooth, flat, and with a maximum surface roughness of 32 micro-

inches rms.

 Optional: Apply a light coating of coupling fluid (machine oil or silicone grease) on the mating surface

to maximize the usable frequency range.

 Torque screws to recommended limits using steel washers under the heads of the mounting screws.

Use manual torque wrench (do not use electric tools).

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Adhesive Mounting

To avoid damaging the accelerometer during subsequent removal, it is recommended to use an
adhesive mounting adaptor for this method of attachment. For adhesively mounting of accelerometers
the following guidelines should be followed:

 The mounting surface should be clean and free of any residue or foreign material.
 The mounting surface should be smooth, flat, and with a maximum surface roughness of 64 micro-

inches rms.

 For best high frequency performance a cyanoacrylate adhesive is recommend. A thin layer offers

best frequency response.

 Soften adhesive cured adhesive with a chemical debonder (eg. acetone) prior to removal. Gently

shear accelerometer loose from the mounting surface after waiting a few minutes for the debonding
agent to penetrate the epoxy. Make sure not to use excessive force as this may damage the
accelerometer.

Biaxial Mounting Configurations

The model 4623 accelerometer has a unique housing that enables it to be mounted in two different
orientations to measure either the normal or transverse acceleration input. By simply rotating the housing
90 degrees, the accelerometer can now be used to measure transverse motion. The two mounting
orientations are illustrated below.

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Wiring
The accelerometer is designed to be operated from 7-30Vdc excitation and provide a ±2V full scale

output with a 2.5V reference voltage. The output is DC-coupled and can be used in either single-ended
or differential mode. Differential mode offers the best performance since common mode errors are
minimized. The electrical hookup for both modes of operation is detailed below.

Single-Ended Operation

For single-ended operation a 2.5Vdc bias will be present on the output leads and the output of the
accelerometer will be 0.5-4.5V full scale. For single-ended operation the accelerometer should be
connected to the signal conditioner as detailed below. To avoid permanently damaging the

accelerometer, the white wire should not be connected to ground.

SINGLE ENDED OUTPUT

Differential Operation

For differential operation the output of the accelerometer will be ±2V full scale without a bias voltage
present. For differential operation the accelerometer should be connected to the signal conditioner as
detailed below. Common mode voltage is 2.5V.

DIFFERENTIAL OUTPUT

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Cable Routing

The model 4623 accelerometer incorporates a FEP jacketed cable with an integral shield. The cable
assembly should be properly secured at regular intervals during testing. It is recommended to use
clamps, wax, or tape to secure the cable to minimize cable motion that can add noise to the output
signal. The initial attachment should be within two to three inches of the accelerometer with some slack
in the cable to prevent tension at the connector joint

Avoid routing cables near high-voltage wires and also ground the shield at the signal conditioner to
minimize ground loops.

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FULL SCALE

RATING

(g-pk)

SENSITIVITY

(mV/g)

±5% AMPL

PASSBAND

(Hz)

PASSBAND

NOISE

(µVrms)

SPECTRAL

NOISE

(µg-rms/√Hz)

DYNAMIC

RANGE

(dB)

2

1000

150

500

35

72 5 400

150

500

38

76

10

200

200

450

75

76

25

80

400

550

219

75

50

40

600

450

316

74

100

20

1000

450

516

74

Noise Floor Specifications

The model 4623 accelerometer incorporates a LP filtered output for a high output signal. The noise
specifications for this accelerometer are detailed in table below.

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Typical Phase Response

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

15

20

25

30

35

40

10 100 1000 10000

Frequency (Hz)

Phase (degrees)

2g Range
10g Range
30g Range
50g Range
100g Range
200g Range

Typical Frequency Response

-40

-35

-30

-25

-20

-15

-10

-5

0

5

10

15

20

25

30

35

40

1 10 100 1000 10000

Frequency (Hz)

Sensitivity Deviation (%)

2g Range
5g Range
10g Range
25g Range
50g Range
100g-500g Range

Frequency Response & Phase Deviation Curves

The typical frequency response and phase deviation curves for the model 4623 accelerometer are
illustrated below.

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