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2-30 A c c e l e r o m e t e r S e l e c t i o n G u i d e – A m p l i f i e d

Model 3145

• Vibration/Shock Monitoring

• Geophysical Monitoring

• Modal Analysis

• Structural Analysis

• Elevator Ride Control

Signal Conditioned Accelerometer

0.5 to 4.5 VDC Output

Intergral Temperature Compensation

High Performance

DESCRIPTIONThe Model 3145 is a general purpose performanceaccelerometer intended for instrumentation applications. The3145 provides a fully signal conditioned output withperformance similar to traditional instrumentationaccelerometers but at a much lower cost.

The accelerometer consists of a silicon micro machinedaccelerometer with signal conditioning electronics in alightweight Valox housing that can be easily attached to amounting surface.

The sensing element is a micro machined silicon masssuspended by multiple beams from a silicon frame.Piezoresistors located in the beams change their resistance asthe motion of the suspended mass changes the strain in thebeams. Silicon caps on the top and bottom of the device areadded to provide over-range stops. This design provides for avery low profile, high shock resistance, durability and built-indamping over a wide usable bandwidth.

A higher performance version of the 3145 is available forcritical applications. Please refer to the Model 3140 foradditional information.

FEATURES• Bolt Mount• ±0.5% Non-linearity (typical)• ±4.0% Temperature Performance• DC Response• Built-in Damping• Built-in Overrange Stops• Low Power

STANDARD RANGESRange g

±2 •±5 •±10 •±20 •±50 •±100 •

DIMENTIONS

Internet :www.msiusa.comTel : 1-757-766-1500

North America Tol l Free: 1-800-745-8008Fax: 1-757-766-4297

A c c e l e r o m e t e r S e l e c t i o n G u i d e – A m p l i f i e d 2-31

Signal Conditioned AccelerometerModel 3145

3145 - 002

Acceleration RangeModel

CONNECTIONS

PERFORMANCE SPECIFICATIONSSupply Voltage: 12 VDCAmbient Temperature: 25°C (Unless otherwise specified)

RANGE______________________________________________________________________________________________________PARAMETERS ±2g ±5g ±10g ±20g ±50g ±100g __________________________________________________________________________________________________________________________________________________Frequency Response [MIN] 0-200 0-300 0-400 0-500 0-600 0-1500 __________________________________________________________________________________________________________________________________________________Mounted Resonant Frequency [MIN] 450 600 950 1500 2750 3000__________________________________________________________________________________________________________________________________________________

Sensitivity (MIN/MAX) 1 V/g 400mV/g 200mV/g 100mV/g 40mV/g 20mV/g

PARAMETERS MIN TYP MAX UNITS NOTES__________________________________________________________________________________________________________________________________________________Full Scale Output Span 3.80 4.00 4.20 Volts 1, 2__________________________________________________________________________________________________________________________________________________Zero Acceleration Output 2.40 2.50 2.60 Volts 1, 2__________________________________________________________________________________________________________________________________________________Accuracy 0.5 1.0 ±% Span 3__________________________________________________________________________________________________________________________________________________Transverse Sensitivity 1.0 3.0 ±% Span__________________________________________________________________________________________________________________________________________________Temperature Error - Span (-20 to 85°C) 2.0 4.0 ±% Span 2, 4__________________________________________________________________________________________________________________________________________________Temperature Error - Zero (-20 to 85°C) 2.0 4.0 ±% Span 2, 4__________________________________________________________________________________________________________________________________________________Supply Voltage 8.0 12.0 30.0 Volts__________________________________________________________________________________________________________________________________________________Supply Current 5.0 mA__________________________________________________________________________________________________________________________________________________Reference Voltage 2.5 Volts 5__________________________________________________________________________________________________________________________________________________Output Resistance 0.1 Ω__________________________________________________________________________________________________________________________________________________Output Noise 0.5 mV p-p 6__________________________________________________________________________________________________________________________________________________Output Load Resistance 2 kΩ__________________________________________________________________________________________________________________________________________________Acceleration Limits 20X Rated __________________________________________________________________________________________________________________________________________________Operating Temperature -20°C to +85°C__________________________________________________________________________________________________________________________________________________Storage Temperature -40°C to +125°C__________________________________________________________________________________________________________________________________________________Weight (Including Cable) 13 Grams

1. The output voltage increases from the Zero Acceleration Output for positive accel-eration and decreases for negative acceleration. The sensitivity is then 2V/Range.For example, the ±5g range has a sensitivity of 2V/5g or 400mV/g.

2. Actual test data for this parameter is included on the calibration sheet providedwith each sensor.

3. Includes repeatability, hysteresis, and linearity (best fit straight line).4. Compensated temperature range: -20°C to +85°C in reference to 25°C.5. Pin 2 provides an optional 2.5V reference which may be used, if desired, to pro-

vide a stable zero-g reference. Thus, the full scale differential output between Pin 2and Pin 4 would be ± 2 VDC. If a single ended output signal is preferred (0.5-4.5

VDC), make no connection to Pin 2. To avoid damage to the internal voltage regu-lator, do not connect Pin 2 to Pin 1 (gnd). Minimum load resistance connected toPin 2 without affecting output is 100 k

6. 10 Hz to 1 kHz.7. To use an alternate electrical connector, refer to the following color code for prop-

er electrical connections: Pin 1 - Green; Pin 2 - Yellow; Pin 3 - Red; Pin 4 - Blue;Pin 5 - Shield. Note: Removing the connector voids the product warranty.

8. The useful frequency range is defined as the range of frequencies overwhich the device sensitivity is within ±5% of the DC value.

Notes

ORDERING INFORMATION

Dec 2002*Notch on connector to indicate pin one.

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