MTS Series 793 User Manual
Page 205
Extensometer Calibration
MTS Series 793 Tuning and Calibration
Calibration Procedures
205
Note
Before using Auto Zero, ensure that any offsets due to Auto Offset and
Manual Offset actions are eliminated.
5. Use Auto Zero to zero transducer output.
Standalone FlexTest SE Controllers: Select Setup > Strain > Offset/Zero
> <<Auto Zero>>
Automated Controllers: Click Auto Zero on the Calibration tab to set
transducer’s amplified output to 0.000 V DC.
Initial extensometer
calibration
If you have previously calibrated this extensometer, see
on page 207. If this is a first-time calibration, use the following
procedure:
1. Adjust the calibrator between zero and -100% of the extensometer’s full-
scale range three times. This exercises the extensometer to remove any
hysteresis.
2. Set the calibrator micrometer to a value that is 80% of the negative full scale
range.
3. Verify that your extensometer feedback signal is -80% of the full scale
range.
During the initial calibration of your system, it may require repeated
adjustment for the negative strain calibrator setting and feedback values to
match.
At this point, unless the conditioner is already in calibration, the negative
strain reading will not equal the value set on your calibrator micrometer.
You will adjust gain in the next step so that the actual strain and your
calibrator strain setting match.
4. Set an initial gain of 500.
5. Adjust Excitation so that the strain signal approaches the target value. As
the target value is approached, determine an appropriate integer or half-
integer value (e.g., 6.5 V). Then, make finer adjustments to the sensor
output using Post-amp Gain.
6. Set the calibrator micrometer to a value that is 80% of the positive full scale
range.
Note
Since you are using a Model 493.25 conditioner, with no Delta K
adjustment, you can only adjust Post-amp Gain at one point, either the
+80% point, or -80% point. The other point (+80% or -80%) simply
becomes a data point value for the linearization table.