Shure 62CP User Guide

ACCELEROMETER

GENERAL

The Shure Model 62CP is a ceramic accelerometer
having a Lead Zirconate Titanate (PZT) element.
This unit features:

m

Very high voltage sensitivity
High internal capacitance
Extremely small temperature coefficient

of sensitivity for good stability
High resonant frequency
Construction unaffected by humidity

The high output and high capacity make the pickup
especially useful for measuring low accelerations,
measuring where electrical noise is high, and measur­ing with relatively long cables. The output voltage is
proportional to acceleration throughout the linear range
of the pickup. A signal proportional to velocity may
be derived from a simple RC integrator. Further in­tegration gives a signal proportional to displacement.

Other uses include routine vibration measurements
and engineering vibration studies of all types of ma­chinery, vehicles and motors, shock mountings, build­ing construction, and sources of noise caused by
structure-borne vibrations.

FREQUENCY CHARACTERISTICS

Frequency response curves for constant acceleration

1.

are shown in Figure
62CP Pickup is constant up to approximately
and has a value of about 600 millivolts per g with a
200 pF cable. The total frequency range of the pickup
extends to about

4500 Hz where the resonant frequen-

cy occurs.

The internal impedance of the instrument with a

200

pF cable is approximately equivalent to that of a

950 pF capacitor; therefore the low-frequency re-

sponse characteristic is dependent upon the load

R

resistance

employed, as indicated in Figure
reduction in low-frequency response obtained by con­necting the pickup to a low load resistance is a
decided advantage in some situations. For general ap­plications, a resistance of
For studying low-frequency vibrations (about
a

30

to

50

megohm or greater termination should
be used.

10.0

6.0

4.0

Y

2

2.0

_I

?

1.0

2

0.6

:

0.4

0.2

0.1

0.06

20

FREQUENCY RESPONSE

The voltage sensitivity of the

1000

10

megohms is suitable.

10

FREWENCY

FIGURE

IN

lp00

MRTZ

1

1o.ow

1.

Hz

The

Hz),

24ooo

Frequency characteristics

MODEL

of

the pickup may be

62CP

modified, if desired, by means of simple electrical
networks. In all cases, the complete circuit, including
the network itself, should be fully shielded to prevent
hum pickup.

Although the 62CP responds only to acceleration,

the use of integrating networks will give velocity and

of

displacement information. The simplest form

in-

tegrating network is a series capacitor and resistor.

of

The output

the 62CP is impressed across the series
circuit and the integrated voltage appears across the
capacitor.

portional to the velocity
integrating circuits in series will give

A

single circuit will yield a voltage pro-

of the moving object. Two

a

voltage repre­senting the displacement of the object. Calculating
the values for the integrating circuit is simple, but
attention should be paid to the values

is not "loaded" and to the time constant

so

the 62CP

of the circuit,

so as to properly integrate the lowest frequency of

interest. Typical values would be

1,000

pF. See Figure 2 for typical circuits and curves.

SPEC1

FI

CAT1

O

10

megohms and

PIS

Type

Piezoelectric (lead zirconate titanate)

Typical Output

On Axis

730 t200 mV/g

Off Axis

5%

Less than

of on-axis output

Impedance

770 picofarads

Recommended Load Impedance

Determined by requirements for low-frequency roll­off (see Figure

1)

Linear Frequency Range

1

megohm load..

10

megohm load

500

megohm load. ...

.

. . . . .I60 to 1200 Hz

........

16 to 1200 Hz

....

0.32 to 1200 Hz

Copyright

27A326

(SF)

1979,

Shure

Brothers

Inc.

(OVER)

Printed

in

U.S.A.

OUTPUT

FOR

,001

I

I I I

A CONSTANT

500

DOUBLE DISPLACEMENT -SHOWING MODIFYING
NETWORKS AND TYPICAL CORRESPONDING FREOUENCY
CHARACTERISTICS

20

50

100

FREQUENCY IN HERTZ

,0254

I

IIII

1000

MICRON

(1000

5000

,uINJL

TYPICAL INTEGRATING CIRCUITS AND CURVES

FIGURE

2

10,000

Case

Anodized aluminum

Net Weight

85

grams (3 ounces)

(less cable)

Shipping Weight

142 grams

(5

ounces)

Overall Dimensions

See Figure

TO

FIT

CONNECTOR

AMPHENOL-

'5116-037575

3

BORG

OVERALL

FIGURE

?Ll

2.8

mm

DIMENSIONS

3

Environmental Conditions

Temperature

-40" to

94°C

(-40" to 200°F)

Humidity

0

to

100%

RH with no damage, not immersible

Temperature Coefficient of Sensitivity

-.0072 dB per "C (-.004 dB per OF)

1/4"-28.

4.8mrn(J/lb

MIN.

THREAD DEPTH

IN.)

7

Resonance Frequency

4,500

Hz

Dynamic Range

(minimum)

200g

Charge Sensitivity

560 2200 picocoulombs/g

Acoustic Pickup

0.125 mV/microbar at 1000

(maximum)

Hz

Pickup Connector

Microdot type 33-01

Cable

2.1

m

(7

ft) single-conductor shielded, with vinyl

jacket and Amphenol-Borg type

51

16-037575 con-

nector

I

I

This Shure product is guaranteed in normal use to

be free from etectrical and mechanical defects for a

of

period

one year from date of purchase. Please

retain proof of purchase date. This guarantee includes
all parts and labor. This guarantee is in lieu of any
and all other guarantees or warranties, express or

implied, and there shall be no recovery for any con­sequential or incidental damages.

Carefully repack the unit and return it prepaid to:

Shure Brothers Incorporated

Attention: Service Department

1501 West Shure Drive
Arlington Heights, Illinois 60004

If outside the United States, return .the unit to your
dealer or Authorized Shure Service Center for repair.
The unit will be returned to you prepaid.

GUARANTEE

SHIPPING INSTRUCTIONS