MTS Series 793 - Manual (Page 127)

Shunt Calibration
MTS Series 793 Tuning and Calibration Calibration Procedures 127
How to perform a shunt
calibration
Shunt calibration is a feature available for DC conditioners. It checks the
integrity of the conditioner/sensor combination. It works by shunting a precision
resistor across one arm of the sensor’s Wheatstone bridge. The resulting
imbalance provides a reference value for later use. Shunt calibration also lets you
replace DC conditioners without affecting the sensor calibration accuracy.
Note The following procedure requires that a valid shunt reference value has
already been established. Establishing a shunt reference value involves
selecting and installing precision shunt resistors, and is a part of detailed
calibration instructions included in this manual. For information about
establishing shunt reference for force sensors, see
page 182 , and for
strain sensors, see page 210 .
1. Turn on hydraulic power.
2. Zero the DC sensor output.
Standalone FlexTest SE Controllers:
Use the Manual Offset control (Setup > Force > Offset/Zero > Manual
Offset) to achieve a 0 kN output.
Automated Controllers:
Adjust the Manual Cmd slider on the Manual Command window to
achieve a 0 kN output.
3. If necessary, change the control mode.
Shunt calibration cannot be performed on a sensor when it is in control of
the servo loop.
Standalone FlexTest SE Controllers:
Select Status > Control Mode > displacement.
Automated Controllers:
Change Control mode on the Manual Command window to a
Displacement control mode.
Note If you only want to view the current shunt value without changing the
shunt reference value, the operator access level is adequate.
4. Select an access level of Calibration.