MTS Multipurpose Elite - Manual (Page 353)

Caution :
A high-speed transition segment can result in an unwanted spike (or bump) in your command
signal.
Unwanted command-signal spikes can damage the physical test specimen.
To avoid spikes in the command signal, use a Ramp activity to bridge where end levels and
start levels differ greatly. If an activity end level is not near the start level of your cyclic
command, the activity uses the first segment to move all the way from the current level to the
start level at the transition speed that you specify.
Cycles and segments
You can repeat cycles or segments. Two segments create one cycle. Repeating a full cycle first goes to
end level 1 and ends at end level 2. Repeating a segment can end at end level 1 or end level 2, depending
on whether the count value is odd or even.
The conventional way to define the duration of a cyclic command is by frequency or time.
End Levels
Note:
The end levels can be set to values greater than the full scale. In that scenario, the command
attempts to reach the specified end level; however, the feedback becomes saturated before reaching
the specified end level, causing a hydraulic interlock.
End levels
The two end levels specify the amplitude of the waveform. When two test command activities with different
end levels are sequenced, the transition between them is accomplished at the rate and segment shape
of the following activity. This provides a smooth transition between test commands.
Example
Suppose you run a Sweep activity that completes a cyclic command at End Level 2 (in this case, +2 cm).
Next, suppose you run another Sweep activity in which End Level 1 = –1 cm and End Level 2 = +1 cm.
The transition segment bridges the two commands from the +2 cm level to the –1 cm level at the time,
rate, or frequency of the second activity.
MTS TestSuite | 353
Test Activities