MTS Series 793 - Manual (Page 46)

MTS Series 793 Tuning and Calibration
About Calibration
Introduction 46
Extensometer calibration Extensometers require special test fixtures to aid in calibration.
LVDT calibration
LVDTs are calibrated with a dial indicator or ruler. The indicator is mounted
between the actuator rod and a stationary point such as the load unit’s platen. A
typical LVDT has a positive and a negative output. This is usually considered as
tension and compression, but it is actually a motion each way from its
centerpoint. One output is calibrated with gain (typically compression) and the
other output is calibrated with delta K (typically tension).
Shunt calibration Shunt calibration is a feature available for dc conditioners. It checks the integrity
of the conditioner/sensor combination. When a sensor range is calibrated, a shunt
calibration resistor is selected.
The system gives you the capability of verifying calibration accuracy by shunting
a precision resistor across one arm of the sensor’s Wheatstone bridge. The
resulting imbalance provides a reference value for later use.
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