MTS Series 793 - Manual (Page 145)

Displacement Sensor Calibration
MTS Series 793 Tuning and Calibration Calibration Procedures 145
C. Verify that your LVDT displacement signal equals 80% of the full scale
range.
Automated Controllers:
A. Open the Manual Command window, and then click on the Enable
Manual Command.
B. Adjust the Manual Cmd slider on the Manual Command window for
80% of the full scale range.
C. Use the Station Signals panel to verify that your LVDT displacement
signal equals 80% of the full scale range.
During the initial calibration and tuning of your system, it may take a while
for the two values to match.
Note If the actuator response is sluggish and/or the signal value does not
match the command, you will need to adjust the tuning of this control
mode. Increase the proportional gain (P Gain on the Tuning menu) to
correct sluggish actuator movement. Increase the reset integration value
(I Gain) to help the feedback match the command.
At this point, unless the conditioner is already calibrated, the actuator’s
physical extension will not equal your commanded value. You will adjust
Delta K in the next step so that the actuator’s physical extension and your
commanded extension match.
Example: Suppose your actuator has a 100% extension of 10 cm. In this step
you would apply a 8 cm command, and even though the station signals
would read 8 cm of feedback, the actuator may extend only 4 cm. This
shows the conditioner/sensor pair are out of calibration.
6. Adjust Delta K to extend the actuator until it equals your extension
command.
Adjust Delta K until the dial indicator or other readout device shows that
the actuator’s physical extension equals your extension command.
7. If applicable, repeat steps 5 and 6 for all ranges.
Example: Suppose you have an actuator with a full-scale capacity of ±10 cm
and ranges of ±10 cm, ±5 cm, ±2 cm, and ±1 cm. In this case you would
repeat this process and calibrate extension at 80% of each range (8 cm, 4
cm, 1.6 cm, and 0.8 cm).
Note Some systems use full-range conditioners (e.g., Model 493.25 DUC
module). In this case, only one range is used (typically 100%).