Kaman digiVIT - Manual (Page 18)

www.kamansensors.com PART NO: 860525-001
Last Revised 9/16/2013
- 18 -
The calibration is now complete. If the output reads 100.00% (or close to it) the calibration is
good. If 'Cal Error' is displayed, the digiVIT did not acquire enough analog to digital converter
counts between readings and the calibration sequence must be repeated.
6.5 21-Point Piecewise Calibration
Note: Any previous temperature compensation calibration will be voided when a 21 Pt.
calibration is performed.
The 21 point calibration requires more displacement positions but is the most flexible and will
calibrate to almost any curve as long as it is monotonic and there is enough output between
sensor data points. If the fixturing is accurate it almost always yields excellent results. This
calibration assumes nothing about the sensor output as it is a piecewise table lookup approach.
It will result in typical non-linearity on the order of 0.1%. Most of the procedure is the same as
the 6 point calibration except with more data points. This procedure assumes the range is
divided into 20 equal intervals. For example: a 0.5mm range is divided into 0.5/20 = 0.025mm
intervals.
1) Set the sensor flush with the target and move the micrometer to the MIN (offset) position.
Zero the micrometer.
2) Position the sensor at the desired MAX (full scale range + offset) position.
3) Select 'Cal Setup -> Lineariz Output -> 21 Pt. Pcws Cal.'. The unit will prompt to 'Goto MAX
Prs Entr'. With the sensor at full scale press the <enter> button. The unit will prompt 'Scanning
Pls Wait' -- this can take approximately 20 seconds. The unit is optimizing the setup for the
particular sensor, range, and target. Wait for this to finish.
4) The digiVIT will prompt 'Goto MIN Prs Entr'. Go to the MIN position and press <enter>.
5) The digiVIT will prompt 'Goto 5% Prs Entr'. Go to the 5% (0.025mm in our example) position
and press <enter>.
7) Repeat step 5 for 10-95% positions.
5) The digiVIT will prompt 'Goto 100% Prs Entr'. Position the micrometer to the MAX position
and press <enter>.
The calibration is now complete. If the output reads 100.00% (or close to it) the calibration is
good. If 'Cal Error' displayed, the digiVIT did not acquire enough analog to digital converter
counts between readings and the calibration sequence must be repeated.