 |
|||
|
|
|||
| ||||||||||
|
|  MIL-S-18471G(AS)
APPENDIX
b.
Steady state accuracy expressed as a percent of full scale
and combining on a root-mean-square (RMS) error basis, and the
contributions of repeatability, hysteresis, noise, long-term
drift, temperature, etc. RMS transducer error shall not
exceed 1 percent of nominal full scale range for accelero-
meters and 2 percent for rate sensors.
c.
Bandpass cutoff, order, and tolerance. If on-line filtering
is used, the filter's cutoff frequency and tolerance, order
and type shall also be listed, The filter shall not reduce
the transducer's minimum passbands. Accelerometers shall
have a minimum passband of 0-200HZ and rate sensors a minimum
passband of 0-100HZ.
d.
Damping ratio. Accelerometers must exhibit damped response
with a damping ratio of no less than 0.6 of critical. Rate
sensors shall be free of resonance in the 0-300HZ range.
accelerometers and angular sensors shall be aligned to provide outputs in
terms of the X, Y, and Z axes defined in figure 5.
30.3.5 Data acquisition system. The approved test facility shall include
a data acquisition system capable of transmitting, conditioning, and recording
ejection test signals generated by sled, ejection seat, and dummy mounted
instrumentation. The data acquisition system shall be such that it will not
reduce the transducer's minimum passband characteristics. Digital recording
shall be used in preference to analog recording. Data shall be acquired in
accordance with IRIG standards. Telemetry equipment shall comply with MIL-STD-
1572 and MIL-STD-1573.
30.3.6 Calibration. Transducer calibrations shall be current, traceable
to the National Bureau of Standards, and available for inspection by the
procuring activity. Transducers showing evidence of damage or suspected of
internal damage shall be removed for recalibration. The data acquisistion
system shall be calibrated prior to each test using a simulated signal
wherein each sensor is replaced by a known voltage source in several steps
over the full signal range, first ascending and then descending. System
calibration runs shall include the timing channel.
30.3.7 Accuracy. End-to-end instrumentation accuracy for each data
channel shall be established on the basis of transducer and data acquisition
system characteristics and included in the test plan.
30.3.8 Data analysis. Analysis of test data to establish compliance
with specified values shall comply with the below listed requirements:
a.
Test data filtered prior to transmission shall be used without
further filtering.
b.
Data obtained without filtering shall be filtered prior to
further analysis using a low pass filter having detailed
characteristics as listed in the test plan. This filter
shall not reduce the sensor's specified minimum passband
82
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |
Click
here for thousands of PDF manuals