Frequency/amplitude breakpoints are entered in an easy to read tabular form using either frequency and amplitude breakpoints, or by entering one endpoint and the desired dB/octave slope. Over 1000 separate frequency/amplitude breakpoints can be entered, allowing entry of virtually any test.

The controller comes standard with user-selectable 50 to 13,000 lines of control to provide you with the frequency resolution required for your test. You can analyze to 20,000 Hz with the VR657 High Frequency option, without sacrificing resolution.

The control signal can be a single input channel, or configured from 2 to 32 input channels with either multi-channel averaging or optional multi-channel notching.

From 1 to 4 control loops can be run simultaneously to independently control up to 4 shakers with 4 individually configurable and statistically independent waveforms.

Tests can be scheduled to run a user-defined length of time, the spectrum level can be scaled by a specified dB-level, percentage, or scaled for a specified RMS acceleration. Level schedules can be entered to run various durations at different acceleration levels. Levels can be changed while the test is running

Allows more than one input channel for control in a control strategy where the highest accelerometer reading will be used for control of the test.

Assign maximum limiting breakpoint profiles to individual channels. The drive output will be limited (or 'notched') if necessary to keep the input spectrum for that channel below the defined profile. Up to 1024 breakpoints can be entered for each channel, or the limit can be entered simply as a dB level relative to the demand profile. In addition, minimum limits may be defined to boost the drive output if a channel is below a defined profile. The notching profiles may also be used as spectrum abort limits, so that abort limit breakpoint profiles can be assigned to each individual channel, and if that channel reaches the defined limit the test will safely shut down.

Import analog or digital time data to automatically generate a profile. Import PSD data, too.

To protect your test article and shaker system, configurable acceleration limits, line limits, and drive limits can be set by the user. The control input is also verified against shaker acceleration and displacement limits.

All of the test data can be stored to the disk for later retrieval. Data storage can be done manually, or programmed to automatically save at user-defined intervals.

The second output channel supplies an inverted copy of the main output channel.

Many graphical display options are available, including acceleration spectral density, output voltage spectral density and channel-to-channel transmissibility. Graphs can be easily auto-scaled or zoomed, and cursors displayed. Data and text annotations can be easily placed on the graphs, with data values updated live as the data changes.