MTS Fatigue Template - Manual (Page 108)

Description Item
Sets the amount of change that must occur in the
maximum load between saves to disk. Load Storage
Change
Sets the value of N, which is the rate (number) of
peak-valley cycles for a store to disk to occur. For PV Nth Cycle
Stored
example, if this parameter is 100, data is saved to
disk every 100 cycles.
Sets the number of cycles to save to disk at the
beginning of the test or when the test is started. Starting Cycles
Sets the number of cycles of time data per decade
based on a logarithm to save to disk. Time Cycles Per
Log Decade
Stored
Sets the number of levels between saves to disk. Number of Levels
Sets the range the data must exceed to detect the
peak-valley data. Within this range, points are
considered noise and not peak or valley data. Strain Noise Band
Percent
Sets the amount of change that must occur in the
displacement between saves to disk. Displacement
Storage Change
11.2.5.0 Extensometer Calibration
Extensometer verification
Extensometer calibration ensures accurate data collection. You should verify the extensometer calibration
before performing any testing. To verify extensometer calibration, set the system to load control and ramp to
zero load. At zero load, the strain extensometer is zeroed.
An extensometer includes a strain gage. You should verify its calibration before you run a test. You can verify
the calibration accuracy of a DC sensor/conditioner pair through shunt calibration. Shunt calibration works
by shunting a precision resistor across one arm of the sensor’s Wheatstone bridge. The resulting imbalance
provides a reference value that is recorded on the calibration data sheet that accompanies the sensor.
Note:
With systems that use Series 494 hardware, you can use the HWI Editor application to select the arm
of the bridge where the shunt calibration resistor will be applied.
A current shunt calibration value, taken before a test, should be compared to the shunt calibration reference
value recorded when the sensor was last calibrated. If the reference value and the current value differ too
greatly, the sensor/conditioner pair should be recalibrated to establish a new shunt reference value.
Significant variations between current and reference values can occur if the excitation voltage has drifted, or
the sensor has been damaged or has changed in some other way. It is possible to adjust excitation to
compensate for small-to-moderate changes in the shunt calibration value.
108 MTS TestSuite
11.0 ASTM Trapezoidal Strain Elevated Temperature Template