Variable Capacitance Accelerometer
Model 7596A
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Economical and Rugged
2 to 100 g Full Scale
DC Response
Gas Damped Sensor
Mechanical Over-range Stops
Actual size
ENDEVCO
MODEL
7596A
DESCRIPTION
The ENDEVCO
®
Model 7596A VALULINE™
accelerometer family is a low cost solution to low-level,
low frequency measurements. Applications include labora-
tory measurements, ground transportation studies and mea-
surements where the accelerometer will be subjected to
high shock levels (up to 10 000 gs, see specifications).
The 7596A is ideal for modal studies on large structures.
Gas damping and internal overange stops enable the
anisotropically etched silicon microsensors to withstand
high shocks and acceleration loads. The use of gas damp-
ing, in the sensor, results in very small-induced changes of
frequency response. The patented sensor design ensures
immediate stability making the unit ready to take accurate
DC or dynamic data within one millisecond!
The 7596A can operate from 8.5Vdc to 30Vdc and pro-
vide a high level, low impedance output. The output is
high enough to drive most laboratory instruments, tape
recorders and data acquisition systems without amplifica-
tion or signal conditioning. The output can be fed into
either a differential or single-ended amplifier or standard
bridge electronics with 10Vdc excitation.
ENDEVCO Model 136 Three-Channel System, Model
4430A or OASIS Computer-Controlled
System are
recommended signal conditioners.
SPECIFICATIONS
PERFORMANCE CHARACTERISTICS:
All values are typical at +75°F (+24°C) and 15 Vdc excitation unless otherwise stated. Calibration data, traceable to
the National Institute of Standards, (NIST), is supplied.
Units
g pk
mV/g
Hz
Hz
% FSO Typ
% FSO (Max)
% Typ
mV Max
%/°F
%/°C
7596-2
±2
1000 ±100
0 to 15
1300
±0.20
±0.50
1
±200
3.0
+0.04
+0.08
-10
±10
200 ±20
0 to 500
3000
±0.20
±0.50
1
±200
0.7
+0.04
+0.08
-30
±30
66 ±8
0 to 800
5500
±0.20
±0.50
1
±200
0.7
+0.04
+0.08
-50
±50
40 ±4
0 to 1000
5500
±0.2
±0.5
1
±200
0.6
+0.04
+0.08
-100
±100
20 ±2
0 to 1000
6000
±1
±2
1
±200
0.6
+0.04
+0.08
RANGE
SENSITIVITY (at 100 Hz) [1] [2]
FREQUENCY RESPONSE (± 5%)
MOUNTED RESONANCE FREQUENCY
NON-LINEARITY AND HYSTERESIS [3]
TRANSVERSE SENSITIVITY [4]
ZERO MEASURAND OUTPUT [2]
DAMPING RATIO
DAMPING RATIO CHANGE
From -65°F to +250°F ( -55°C to +121°C)
APPLIES TO CALIFORNIA FACILITY
ENDEVCO
Variable Capacitance Accelerometer
SPECIFICATIONS—continued
PERFORMANCE CHARACTERISTICS—continued
Units
7596-2
-10
THERMAL ZERO SHIFT
From 32°F to 122°F (0°C to 50°C)
% FSO Max
±2.0
±2.0
From -13°F to +167°F (-25°C to +75°C)
% FSO Max
±4.0
±4.0
From -65°F to +250°F (-54°C to +121°C)
% FSO Max
±6.0
±6.0
THERMAL SENSITIVITY SHIFT
From 32°F to 122°F (0°C to +50°C)
% Max
±2.0
±2.0
From -13°F to +167°F (-25°C to +75°C)
% Max
±4.0
±4.0
From -65°F to +250°F (-54°C to +121°C)
% Max
±6.0
±6.0
THERMAL TRANSIENT ERROR
Equiv. g/°F
< 0.0006
< 0.0006
PER ISA RP 37.2
Equiv. g/°C
< 0.001
< 0.001
OVERRANGE (Determined by Electrical clipping or Mechanical stops, whichever is smaller.)
Electrical clipping
g
-3.5/+3.8
-18/+19
Mechanical stops, typical
g
±4
±30
Recovery Time
µs
< 10
< 10
THRESHOLD (RESOLUTION) [5]
Equiv. g’s
0.0005
0.0025
BASE STRAIN SENSITIVITY, MAX [6]
Equiv. g’s
0.01
0.01
MAGNETIC SUSCEPTIBILITY [7]
Equiv. g’s
<1
<1
WARM-UP TIME (to within 1%)
ms
10
10
ELECTRICAL
EXCITATION [2]
CURRENT DRAIN [8]
OUTPUT IMPEDANCE/LOAD
RESIDUAL NOISE
ISOLATION
PHYSICAL
CASE, MATERIAL/BASE
ELECTRICAL, CONNECTIONS
MOUNTING/TORQUE
WEIGHT
ENVIRONMENTAL
ACCELERATION LIMITS (in any direction)
Static
Sinusoidal/Random Vibration
Shock (half-sine pulse)
Zero Shift
TEMPERATURE
Operating
Storage
HUMIDITY/ALTITUDE
ESD SENSITIVITY
-30
±2.0
±4.0
±6.0
±2.0
±4.0
±6.0
< 0.0006
< 0.001
-53/+57
±90
< 10
0.008
0.01
<1
10
-50
±2.0
±4.0
±6.0
±2.0
±4.0
±6.0
< 0.0006
<0.001
-87/+95
±200
< 10
0.0012
0.01
<1
10
-100
±2.0
± 4.0
± 6.0
±2.0
±6.0
± 6.0
< 0.0006
< 0.001
-175/+190
±200
< 10
0.025
0.01
< 0.1
10
MODEL
7596A
8.5 to 30 Vdc, 32 Vdc maximum without damage; excitation voltage can be applied to any
lead without damage
4.5 mA Typ, 8 mA Max
50 ohms max/10K ohms resistance minimum, 0.1 µF capacitance maximum
100 µV rms typ, 0.5 to 100 Hz. 500 µV rms typ, 0.5 Hz to 10 KHz
100 MΩ
Anodized Aluminum Alloy
28 AWG silver plated alloy 135, PFA340 Teflon® insulated conductors, spiral shield (SPC), HyperFLEX™
jacket with TFE non-fray, end grip 30 ± 3 inches (760 ± 76mm) long.
Two 4-40 x 3/8 6 lbf-in (0.7 Nm)
10 grams (cable weighs 9 grams/meter)
20 000 g
100 g pk, 20 - 2000 Hz/40 g rms, 20 - 2000 Hz
5000 g, 150 µsec or longer for the -2 and -10; 10 000 g, 80 µsec or longer for the -30 and -100
0.1% FSO typical at 5000 g
-65°F to +250°F (-55°C to +121°C)
-100°F to +300°F (-73°C to +150°C)
Unaffected. Unit is epoxy sealed. Hybrid and sensor are hermetically sealed/unaffected.
Unit meets Class 3 requirements of MIL-STD-883
CALIBRATION DATA SUPPLIED
(noted on shipping box)
SENSITIVITY
(at 5 Hz and 1 g pk, for 2 g range)
(at 100 Hz and 10 g pk, all other ranges) mV/g with 15 Vdc excitation
FREQUENCY RESPONSE
1 to 100 Hz for 7596A-2, 20 to 10000 Hz for all other ranges
ZERO MEASURAND OUTPUT
mV
MAXIMUM TRANSVERSE SENSITIVITY
% of sensitivity
ACCESSORIES (included)
EHW265
(2) SIZE 4, FLAT WASHERS
EH409
(2) 4-40 X 3/8 INCH CAP SCREWS
EHM464
(1) HEX WRENCH
OPTIONAL ACCESSORIES
24328
4 CONDUCTOR SHIELDED CABLE
7990
TRIAXIAL MOUNTING BLOCK
NOTES
1. Reference frequency is 20 Hz on the 2 g range.
2. Over the excitation range 8.5 to 30 Vdc. Sensitivity changes
+0.1%/V typical and zero measurand output changes -0.5
mV/V typical.
3. Full scale output (FSO) is nominally 4 volts.
4. 1% is typical. 1% maximum available on special order.
5. THRESHOLD = MAX. RESIDUAL NOISE; 0.5 TO 100 Hz
SENSITIVITY
6. Per ISA 37.2 at 250 Microstrain.
7. At 100 Gauss, 60 Hz.
8. Current drain increases slightly with increasing excitation; typi-
cal change is +.06 mA per volt from 8.5 to 30 Vdc.
9. Maintain high levels of precision and accuracy using
Endevco's factory calibration services. Call Endevco’s inside
sales force at 800-982-6732 for recommended intervals, pric-
ing and turn-around time for these services as well as for quo-
tations on our standard products.
Continued product improvement necessitates that Endevco reserve the right to modify these specifications without notice. Endevco maintains a program of con-
stant surveillance over all products to ensure a high level of reliability. This program includes attention to reliability factors during product design, the support of
stringent Quality Control requirements, and compulsory corrective action procedures. These measures, together with conservative specifications have made the
name Endevco synonymous with reliability.
ENDEVCO CORPORATION, 30700 RANCHO VIEJO ROAD, SAN JUAN CAPISTRANO, CA 92675 USA (800) 982-6732 (949) 493-8181 fax (949) 661-7231
www.endevco.com
Email:applications@endevco.com
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