Variable Capacitance Accelerometer ENDEVCO Model 7290A MODEL 7290A • • • • • DC Response 2 to 100 g Full Scale Motion, Low Frequency, Tilt Gas Damping 10Kg Shock Survivability 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 7290A-2 ±2 1000 ±20 -10 ±10 200 ±10 -30 ±30 66 ±4 -50 ±50 40 ±2 -100 ±100 20 ±1 Hz Hz % FSO Typ % FSO (Max) % Max mV Max 0 to 15 1300 ±0.20 ±0.50 2 ±50 4.5 +0.04 +0.08 0 to 500 3000 ±0.20 ±0.50 2 ±50 0.7 +0.04 +0.08 0 to 800 5500 ±0.20 ±0.50 2 ±50 0.7 +0.04 +0.08 0 to 1000 5500 ±0.20 ±0.50 2 ±50 0.6 +0.04 +0.08 0 to 1000 6000 ±1 ±2 2 ±50 0.6 +0.04 +0.08 %/°F %/°C APPLIES TO CALIFORNIA FACILITY ENDEVCO Variable Capacitance Accelerometer MODEL 7290A 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 -50 -100 ±1.0 ±2.0 ±1.0 ±2.0 ±1.0 ± 2.0 ±2.0 ±3.0 < 0.0006 < 0.001 ±2.0 ±3.0 < 0.0006 < 0.001 ±2.0 ±3.0 < 0.0006 < 0.001 -53/+57 ±90 < 10 0.008 0.01 < 0.1 10 -87/+95 ±90 <10 0.012 0.01 < 0.1 10 -175/+190 ±150 < 10 0.025 0.01 < 0.1 10 9.5 to 18.0 Vdc, 20 Vdc maximum without damage; excitation voltage can be applied to any lead without damage 8.5 mA Typ, 10 mA Max 500 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 Anodized aluminum alloy Integral cable, four conductor No. 28 AWG, Teflon® insulated leads, braided shield, Hyperflex™ jacket Manufacturer's logo, model number and serial number Holes for two 4-40 or M3 mounting screws/6 lbf-in (0.68 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, -50 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 SENSITIVITY mV/g with 15 Vdc excitation (at 1g and 5 Hz for 7290A-2) (at 10g and 100 Hz for 7290A-10,-30,-50, and -100) FREQUENCY RESPONSE 1 to 100 Hz for 7290A-2, 20 to 10,000 Hz for all other ranges ZERO MEASURAND OUTPUT mV MAXIMUM TRANSVERSE SENSITIVITY % of sensitivity ACCESSORIES EHW265 EH409 EHM464 (2) SIZE 4, FLAT WASHERS (2) 4-40 X 3/8 INCH CAP SCREWS (1) HEX WRENCH OPTIONAL ACCESSORIES 24328 4 CONDUCTOR SHIELDED CABLE 7990 TRIAXIAL MOUNTING BLOCK NOTES 1. Customized range, 7290A-XX, available on special order. FSO is nominally 4 volts. Combined non-linearity and hysterisis is typically ±1% FSO and ± 2% FSO, maximum. 2. Reference frequency is 20 Hz on the 2 g range. 3. Over the excitation range 9.5 to 18.0 Vdc. Sensitivity changes +0.1%/V typical and zero measurand output changes -0.5 mV/V typical. 4. Extended frequency response available on special order to extend to 0-900 Hz for 7290A-10, 0-1500 Hz for 7290A-30, and 0-2000 Hz for 7290A-100. 5. Full scale output (FSO) is nominally 4 volts. 6. 1% is typical. 1% maximum available on special order. 7. THRESHOLD = MAX. RESIDUAL NOISE; 0.5 TO 100 Hz SENSITIVITY 8. Per ISA 37.2 at 250 Microstrain. 9. At 100 Gauss, 60 Hz. 10. Current drain increases slightly with increasing excitation; typical change is +.06 mA per volt from 9.5 to 18.0 Vdc. 11. 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, pricing and turnaround time for these services as well as for quotations on our standard products. NOTE: Tighter specifications available on special order. Continued product improvement necessitates that Endevco reserve the right to modify these specifications without notice. Endevco maintains a program of constant 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:[email protected] 0703 REV E