CATS Random Control
The single most important issue in Random
testing after accuracy is correct random energy.
This means the excitation energy must be, not
only random in frequency, amplitude, and phase
but constantly changing as well. Incorrect
random energy causes the test to fail to conform
to industry test standards. With PUMA you are
guaranteed your excitation is the best Random
available today. The accepted specification for
amplitude variability is described as: 120
Degrees of Freedom (DOF) for control and
WILL vary at least +/- 1dB. It does not say it
MAY. The statistical standard for Random says
it WILL vary +/- 1dB, at least.
Figure 1
• Continuous Control to a PSD rather than
– is a tool that permits PUMA to “see the future”
and adjust the control speed in real time to the
next measure of error that is about to happen.
This ‘look ahead’ feature allows the PUMA to
control problems lesser systems don’t even
“Once per Test” control to the system ID
• One Click Data Reporting
• Choose independent limit profiles for each
active measurement channel
• Determine Frequency Response Function
(FRF) measurements for selected channels
• Easy integration with chambers and other test
• Exceptionally rapid correction for resonant
frequencies – provides excellent protection
against over test
Figure 2
Graphics so POWERFUL, the user
interface can be simple
CATS Random
Control Methods
Control method
Input channels
Input dynamic range
Output dynamics range
Control Performance
Dynamic range
Equalization accuracy
Loop time
Re-equalization rate
Reference Spectrum
Spectral alarm/abort limits
Frequency range (DC to)
Frequency resolution
Import reference
Limit Profiles (optional)
Control Parameters
Number of control channels
Multi-channel control
Mode of operation
Test duration
Degrees of freedom
Output level control
Overlap Processing
Startup Parameters
Initial test level
Time at initial level
Level increment
Pre-stored drive startup
Test Automation Features
Level scheduling
Test scheduling
Print Automation
Technical Specifications
Patented adaptive control algorithm with separate
controls loops dedicated to controlling the shape of the
drive spectrum and overall RMS level optimizes both
control speed and stability
4 to 32;all simultaneously sampled
>94dB with auto-ranging
Safety Features
Shaker limits
Loop check max. drive
Alarm/Abort RMS
Alarm/Abort spectral lines
Channel abort profile
> 90 dB
True Gaussian noise
Control to within ± 1 dB for a flat reference spectrum
with 120 DOF 90% statistical confidence
Channel RMS abort
Control signal loss
Manual abort
External kill-switch
With 4 control channels, 4 new data frames per loop,
2000 Hz, 200 lines 120 DOF, less than 0.5 seconds
For an instantaneous change of 6 dB in all control
spectrum lines, the spectrum RMS is re-equalized to
within ±1 dB within 8 control loops, for a flat reference
with 4 control channels, 120 DOF
Drive signal clipping
Startup/shutdown rates
Easily defined by a combination of up to 500
amplitude/frequency breakpoints, (PSD
value/frequency value) and slopes (dB/octave values)
Independent positive and negative alarm and abort
tolerances for each breakpoint
50, 80, 100, 200, 400, 500, 800, 1000, 2000, 4000,
5000 Hz; 10000 Hz and 20000 Hz (Premier) optional
100, 200, 400 and 800 lines;1600 and 3200 lines
(Premier) optional
g-in/s-in: g-m/s-mm; m/s2-m/s-mm EU for
Measurement Channels)
Copy & paste from spreadsheet program; optional:
import from Universal File Format (Intermediate)
Easily defined by a combination of up to 500
amplitude/frequency breakpoints, (PSD
value/frequency value) and slopes (dB/octave values)
Up to the number of active channels minus 1 (Premier)
1 to all available channels
Average, maximum, minimum; user-defined weighting
for each control channel
Manual, automatic, automatic only
User-defined, maximum 9999:59:59 (hhhh:mm:ss)
User-defined. minimum 8, maximum 30000
Automatic, manual
None, 25%, 50%
Channel Setup
Channel type
ICP power
Channel loop check
Channel label
Transducer serial number
Transducer Database
Control channel weighting
RMS abort
Base Engineering Units
Engineering Units
On-Line Status Monitors
Test status
Level status
Control status
Channel status
Message log
On-Line Controls
Start/Abort test
Resume test
Test Mode
Drive update
On-line Analysis
Real-time displays
User-selectable; -80 to 0 dB
User-defined number of loops
Spectra analyzed
1 to 20 dB
User-selectable (No/Yes/Yes with verify before start)
Averaging control
Real-time/stored data
Up to 500 test levels; each level with programmable
time at level, time between levels, abort/ignore action
Up to 500 tests run automatically; each test with
programmable number of cycles, external start
(requires Remote Control Interface), and delay time
before starting next test (option)
Ability to create reports automatically with
customizable displays
Data Storage
Setup options
Spectral Dynamics, Inc.
2730 Orchard Parkway
San Jose, CA 95134
TEL. 408.678.3500
FAX. 408.678.3580
Run message log
Pretest verification that spectrum dynamic limits are
within shaker operational limits (acceleration, velocity
displacement and voltage)
User-selectable, 0 to 5000 mV RMS
RMS acceleration limit in dB or Absolute units
Number of lines, or percent of lines within userspecified range
User-defined profile for any non-control channel with
up to 500 breakpoints each with + and - dB abort
Aborts test if any channel RMS threshold exceeded
Automatic detection with smooth drive shutdown
Graphical and keyboard abort buttons
Rack or desktop mountable external abort circuit with
programmed shutdown (option)
2 to 20 sigma
Independently selectable 1 to 50 dB/sec
Control, measurement, limit, abort, inactive
0.001 to 9,999 mV/g or mV/(m/s2)
AC or DC
Enabled, disabled
Up to 20 characters for each channel
Up to 10 characters for each channel
Table Driven Archival Database
Individuality defined, 20 to 6 dB
Individually defined, 0 to 999 grms or (m/s2)rms
Label(EU), Conversion (EU/Transducer Unit)
Integrated(Label and Scale), Double Integrated(Label
and Scale),Differentiated(Label and Scale),Double
Differentiated (Label and Scale)
Elapsed and remaining test time
Schedule level number, elapsed and remaining level
Test dB level, drive RMS level, Control Level GRMS
RMS levels for all active channels
Records all test operations, including operator
commands, and reports on alarm or error conditions
Smoothly initiates or terminates test
Restart test and complete remaining time
Manual or automatic
Update of drive spectrum on or off
Step up or step down
Lower drive level to -90 dB, hold until resume
Spectra or time histories for all available channels may
be simultaneously displayed during the test
PSD, auto-spectrum, linear-spectrum, transmissibility,
frequency response function (magnitude/phase or
real/imaginary), coherence,
User-selectable; DOF exponential or linear averaging
Simultaneous display and overlay of spectra or time
histories for real-time data and any stored data
Automatic storage every 1 to 10,000 seconds, save on
level change, save on alarm, save on external
command, manual save
Automatic play of entire test data file, with adjustable
display update delay; manual selection
Text file records all system status messages displayed
during test run
In keeping with our commitment to continuous product improvement, the
information herein is subject to change. Copyright 2005 Spectral Dynamics, Inc.
All rights reserved. CATS and STAR logos are registered trademarks or Spectral
Dynamics Inc. All other trademarks are properties of their respective owners.
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