MTS Series 793 - Manual (Page 138)

MTS Series 793 Tuning and Calibration
Displacement Sensor Calibration
Calibration Procedures 138
1. Fully retract the actuator.
Standalone FlexTest SE Controllers: Using the front panel Dial, adjust the
Setpoint to fully retract the actuator. Select Status > Setpoint
Automated Controllers: Adjust the Manual Cmd slider control on the
Manual Command window to fully retract the actuator.
2. Remove hydraulic pressure.
3. Adjust phase for the maximum conditioner output.
Monitor the appropriate AC conditioner feedback signal. Adjust Phase to
achieve a maximum value.
Standalone FlexTest SE Controllers: Select Setup > Disp > Calibration
> Phase
Automated Controllers: Adjust the Phase control on the Calibration tab
to achieve a maximum value. Use the Station Signals panel to monitor the
appropriate AC conditioner feedback signal
Note When adjusting phase, the LVDT feedback may exceed 10 volts. You
may need to lower conditioner gain before continuing phase adjustment.
Task 5 Set the zero and offset
Establishing zero requires the actuator to be set at mid-displacement when you
calibrate the LVDT for equal amounts of actuator extension and retraction.
Suppose you have an actuator with ±10 cm displacement—which actually has a
20 cm displacement. Setting zero at mid-displacement produces a displacement
of ±10 cm (this is the most common approach). However, you can set zero
anywhere within the full scale of the sensor, such as with the actuator fully
extended or retracted to produce a displacement range of 0 mm - 20 mm.