endevco model 7290A v ariable capacitance accelerometer model 7290A dc response 2 to 100 g full scale motion, low frequency, tilt gas damping 10kg shock survivability description the endevco model 7290A microtron accelerometer family utilizes unique variable capaci- tance 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 sub- jected 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 with- stand 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 con- trolled by the near-critically damped sensors. the use of gas damping results in very small thermally- induced 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. p atents 4,574,327, 4,609,968 and 4,999,735 specifications performance characteristics: all values are typical at +75? (+24?), 100 hz and 15 vdc excitation unless otherwise stated. calibration data, traceable to the national institute of standards, (nist), is supplied. units 7290A-2 -10 -30 -50 -100 range [1] g pk 2 10 30 50 100 sensitivity (at 100 hz) [2] [3] mv/g 1000 20 200 10 66 4 40 2 20 1 amplitude response [4] 5% hz 0 to 15 0 to 500 0 to 800 0 to 1000 0 to 1000 mounted resonance frequency hz 1300 3000 5500 5500 6000 non-linearity and hysteresis [5] % fso typ 0.20 0.20 0.20 0.20 1 % fso (max) 0.50 0.50 0.50 0.50 2 transverse sensitivity [6] % max 2222 2 zero measurand output [3] mv max 50 50 50 50 50 damping ratio 4.5 0.7 0.7 0.6 0.6 damping ratio change %/? +0.04 +0.04 +0.04 +0.04 +0.04 from -65? to +250? ( -55? to +121?) %/? +0.08 +0.08 +0.08 +0.08 +0.08 actual size applies to california facility
units 7290A-2 -10 -30 -50 -100 thermal zero shift from 32? to 122? (0? to 50?) % fso max 1.0 1.0 1.0 1.0 1.0 from -13? to +167? (-25? to +75?) % fso max 2.0 2.0 2.0 2.0 2.0 thermal sensitivity shift from 32? to 122? (0? to +50?) % max 2.0 2.0 2.0 2.0 2.0 from -13? to +167? (-25? to +75?) % max 3.0 3.0 3.0 3.0 3.0 thermal transient error equiv. g/? < 0.0006 < 0.0006 < 0.0006 < 0.0006 < 0.0006 per isa rp 37.2 equiv. g/? < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 overrange (determined by electrical clipping or mechanical stops, whichever is smaller.) electrical clipping g -3.5/+3.8 -18/+19 -53/+57 -87/+95 -175/+190 mechanical stops, typical/minimum g 4 30 90 90 150 recovery time s < 10 < 10 < 10 <10 < 10 threshold (resolution) [7] equiv. g s 0.0005 0.0025 0.008 0.012 0.025 base strain sensitivity, max [8] equiv. g 0.01 0.01 0.01 0.01 0.01 magnetic susceptibility [9] equiv. g < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 w arm-up time (to within 1%) ms 10 10 10 10 10 electrical excitation [3] 9.5 to 18.0 vdc, 20 vdc maximum without damage; excitation voltage can be applied to any lead without damage current drain [10] 8.5 ma typ, 10 ma max output impedance/load 500 ohms max/10k ohms resistance minimum, 0.1 f capacitance maximum residual noise 100 v rms typ, 0.5 to 100 hz. 500 v rms typ, 0.5 hz to 10 khz physical case, material anodized aluminum alloy electrical, connections integral cable, four conductor no. 28 awg, te?n insulated leads, braided shield, hyper?x jacket identification manufacturer's logo, model number and serial number mounting/torque holes for two 4-40 or m3 mounting screws/6 lbf-in (0.68 nm) weight 10 grams (cable weighs 9 grams/meter) environmental acceleration limits (in any direction) static 20 000 g sinusoidal/random vibration 100 g pk, 20 - 2000 hz/40 g rms, 20 - 2000 hz shock (half-sine pulse) 5000 g, 150 sec or longer for the -2 and -10; 10 000 g, 80 sec or longer for the -30, -50 and -100 zero shift 0.1% fso typical at 5000 g temperature operating -65? to +250? (-55? to +121?) storage -100? to +300? (-73? to +150?) humidity/altitude unaffected. unit is epoxy sealed. hybrid and sensor are hermetically sealed/unaffected esd sensitivity 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 endevco model 7290A v ariable capacitance accelerometer specifications?ontinued performance characteristics?ontinued accessories 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. 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 t o 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; typi- cal change is +.06 ma per volt from 9.5 to 18.0 vdc. 1 1. 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 turn- around time for these services as well as for quotations on our standard products. note: tighter speci?ations available on special order. continued product improvement necessitates that endevco reserve the right to modify these speci?ations without notice. endevc o maintains a program of con- stant surveillance over all products to ensure a high level of reliability. this program includes attention to reliability fac tors during product design, the support of stringent quality control requirements, and compulsory corrective action procedures. these measures, together with conservativ e speci?ations 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 0703 rev e
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