MTS Material Test Systems - Manual (Page 46)

than one signal is selected as the input, the underpeak detector will not trigger an interlock unless all of the
selected signals are below the specified level.
6.3.0 Define the Test Parameters
There are several test parameters that must be defined before beginning test setup and operation. These
include selecting the proper calibrated range, defining the test program, calculating the Span and Setpoint
control settings, and determining the levels of the various detectors: DC error, upper and lower limit, and
underpeak.
Before defining these test parameters, the test control mode should be known and the maximum and minimum
test forces or displacements should be determined. The maximum and minimum desired forces/displacements
will be used in the calculation of the detector settings and program scaling.
6.3.1.0 Select Appropriate Range
To maintain accuracy over the entire testing range, the transducer feedback signal for each test controller
can be scaled to take advantage of the ±10 volt signal range of the test controller. This is accomplished
through the use of calibrating ranges for the various transducers.
For each test conducted using the test controller, the operator must determine the range of force, acceleration,
displacement, etc., that the test system will need to monitor and control. When this range represents the
maximum and minimum values to be measured during the test, it is referred to as the “testing range.” Standard
calibration ranges include 100% and 10% of full scale operating range.
Note:
It is important to understand that testing range does not reduce the static force capability of the
associated actuator, but only increase the sensitivity of the electronic control and readout components.
6.3.2.0 Define Test Program
To define the test program, the test control mode and the maximum and minimum test forces and/or
displacements must be known. The test program commands the system to produce the calculated forces or
displacements. This is accomplished by selecting an appropriate waveform (that is, a sine wave, square
wave, triangle wave or ramps) and a frequency.
The maximum/minimum amplitude of a waveform output by the programmer is typically ±10 volts, which
represents ±100% of the selected operating range. The test controller's Span and Setpoint controls are
adjusted to scale the program signal to fit the testing range.
Adjusting the Span control changes the amplitude of the program command signal. Adjusting the Setpoint
control changes the program command mean level offset. Adjusting the program's Span and Setpoint enables
the testing system to produce the forces/displacement required for each specific test.
46 MTS Material Test System Operation
6.0 Getting Started