7290A

Variable Capacitance Accelerometer Model 7290A • • • • • DC Response 2 to 100 g Full Scale Motion, Low Frequency, Tilt Gas Damping 10Kg Shock Survivability ENDEVCO MODEL 7290A Actual size DESCRIPTION The ENDEVCO® Model 7290A MICROTRON® accelerometer family utilizes unique variable capacitance microsensors. The accelerometers are designed for measurement of relatively low level accelerations in aerospace and automotive environments. Typical applications require measurement of whole body motion immediately after the accelerometer is subjected to a shock motion, and in the presence of severe vibrational inputs. Gas damping and internal overrange stops enable the anisotropically-etched silicon microsensors to withstand high shock and acceleration loads. The Model 7290A can operate from 9.5 V to 18.0 V and provide a high level, low impedance output. The ±2 volt differential output is dc coupled at a dc bias of approximately 3.6 V. Frequency response is controlled by the near-critically damped sensors. The use of gas damping results in very small thermallyinduced changes of frequency response. ENDEVCO Model 136 Three-Channel System, Model 4430A or OASIS 2000 Computer-Controlled System are recommended as signal conditioner and power supply. U.S. Patents 4,574,327, 4,609,968 and 4,999,735 SPECIFICATIONS PERFORMANCE CHARACTERISTICS: All values are typical at +75°F (+24°C), 100 Hz and 15 Vdc excitation unless otherwise stated. Calibration data, traceable to the National Institute of Standards, (NIST), is supplied. RANGE [1] SENSITIVITY (at 100 Hz) [2] [3] AMPLITUDE RESPONSE [4] ± 5% MOUNTED RESONANCE FREQUENCY NON-LINEARITY AND HYSTERESIS [5] TRANSVERSE SENSITIVITY [6] ZERO MEASURAND OUTPUT [3] DAMPING RATIO DAMPING RATIO CHANGE From -65°F to +250°F ( -55°C to +121°C) Units g pk mV/g Hz Hz % FSO Typ % FSO (Max) % Max mV Max %/°F %/°C 7290A-2 ±2 1000 ±20 0 to 15 1300 ±0.20 ±0.50 2 ±50 4.5 +0.04 +0.08 -10 ±10 200 ±10 0 to 500 3000 ±0.20 ±0.50 2 ±50 0.7 +0.04 +0.08 -30 ±30 66 ±4 0 to 800 5500 ±0.20 ±0.50 2 ±50 0.7 +0.04 +0.08 -50 ±50 40 ±2 0 to 1000 5500 ±0.20 ±0.50 2 ±50 0.6 +0.04 +0.08 -100 ±100 20 ±1 0 to 1000 6000 ±1 ±2 2 ±50 0.6 +0.04 +0.08 APPLIES TO CALIFORNIA FACILITY ENDEVCO Variable Capacitance Accelerometer SPECIFICATIONS—continued PERFORMANCE CHARACTERISTICS—continued Units 7290A-2 -10 THERMAL ZERO SHIFT From 32°F to 122°F (0°C to 50°C) % FSO Max ±1.0 ±1.0 From -13°F to +167°F (-25°C to +75°C) % FSO Max ±2.0 ±2.0 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 ±3.0 ±3.0 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/minimum g ±4 ±30 Recovery Time µs < 10 < 10 THRESHOLD (RESOLUTION) [7] Equiv. g’s 0.0005 0.0025 BASE STRAIN SENSITIVITY, MAX [8] Equiv. g 0.01 0.01 MAGNETIC SUSCEPTIBILITY [9] Equiv. g < 0.1 < 0.1 WARM-UP TIME (to within 1%) ms 10 10 ELECTRICAL EXCITATION [3] CURRENT DRAIN [10] OUTPUT IMPEDANCE/LOAD RESIDUAL NOISE PHYSICAL CASE, MATERIAL ELECTRICAL, CONNECTIONS IDENTIFICATION 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 ±1.0 ±2.0 ±2.0 ±3.0 < 0.0006 < 0.001 -53/+57 ±90 < 10 0.008 0.01 < 0.1 10 -50 ±1.0 ±2.0 ±2.0 ±3.0 < 0.0006 < 0.001 -87/+95 ±90