MTS Series 793 Application - Manual (Page 310)

MTS MultiPurpose TestWare®
Cyclic Acquisition Process
Data Acquisition Process Descriptions 310
Cyclic Acquisition Process
About the Cyclic Acquisition Process
The Cyclic Acquisition process acquires timed, level crossing, interleaved timed
and level crossing, or peak/valley data from cyclic feedback. You can specify the
segments or cycles from which the process acquires data arbitrarily, or in linear
or logarithmic progressions.
The Cyclic Acquisition process monitors sensor feedback that results from
cyclic command. This process acquires data from feedback according to one of
the following:
• Equal changes in time that you specify (time data)
• Equal changes in amplitude that you specify (level crossing data)
• Both changes in time and amplitude (interleaved timed and level crossing
data)
• Signal reversals which occur outside of a sensitivity level that you specify
(peak/valley data)
Sample uses
You could use this process to sample the load feedback resulting from a long
cyclic fatigue test according to a logarithmic progression, and simultaneously
acquire level crossing and timed data from each sampled cycle.
The process saves all data pertaining to an individual cycle in the buffer, and then
writes the entire cycle’s data to the data file in one block. By default, the process
writes data to the specimen.dat file in the MPT specimen. If desired, the process
will write data to a user-defined data file within the MPT specimen.
Disabling the relative
count feature
If you clear the Relative Cycle or Segment Counts check box, the process will
not acquire data on specified cycles that have occurred before the process was
active.
For instance, suppose you begin a procedure with a Cyclic Command process
that cycles the specimen one hundred times at a small amplitude to precondition
the specimen before acquiring data.
Next, you use another Cyclic Command process to apply one million cycles to
the specimen at a much larger amplitude, and simultaneously acquire data from
the feedback with a cyclic acquisition process.