Kaman KD-2300 - Manual (Page 35)

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Part IV: Calibration KD-2300 Instruction Manual
1. Install the sensor in the calibration or application fixture, ensuring that
when the target is at its closest point to the sensor, there is a gap (see
the Sensor Specifications table in Part 3: EQUIPMENT , page 14 for
offsets). With curved targets, decreasing offset will improve linearity;
for flat targets, increasing offset slightly will improve linearity. In
either case, never allow the target to strike the sensor face.
2. Define the reduced measurement span you will use.
3. Position the target so that it is at the maximum displacement of your
defined span, plus offset. Adjust the Linearity Control (Coarse then
Fine) until the output reads the desired maximum voltage.
4. Position the target at the minimum displacement of your defined span
(plus offset) and adjust the Zero control to read the desired voltage at
that point. The desired voltage does not have to be zero.
5. Position the target at the mid-point between the end points of the desired
span. Adjust the Gain control until the output reads the desired voltage.
6. Reposition the target so that it is at the maximum displacement of the
span relative to the sensor. Note the difference between the actual
reading and the desired reading. Adjust the linearity control (Coarse,
then Fine) until the output reads the desired voltage level, then continue
past the desired reading by an amount equal to the first difference you
noted. This technique is called 100% oversetting and is used to reduce
the number of iterations needed to calibrate the system. For example, if
the output reads 1.350 volts and the desired reading is 1.000, adjust the
Linearity control until the output reads 0.650, or, 1.000-0.350. If the
output reads 0.800, adjust linearity until system output reads 1.200, or,
1.000+0.200.
7. Repeat Steps 3 through 6 as many times as necessary until you reach the
desired output voltage at each point. No further adjustment of the Zero,
Gain and Linearity controls will be needed when proper calibration is
attained.