Kaman KD-2300 - Manual (Page 34)

KD-2300 Instruction Manual Part IV: Calibration
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High Accuracy Band Calibration
DISPLACEMENT
offset
VDC
0
High Accuracy Band
Calibration
CALIBRATED
RANGE
This procedure is used to monitor changes in position that are less than
the specified linear measuring range of your sensor, or when you are
interested in increased accuracy over a smaller range and not concerned
about high accuracy outside of that range.
The high accuracy band procedure maximizes the linearity of output
within a calibrated span. The sensor installed in your system has a
specified linear measuring range that defines system performance
characteristics, such as linearity, resolution and long-term stability.
Maximum linearity is centered on the mid-point of the sensor’s
specified maximum linearity measuring range anywhere between 25-
75% of full-scale. For example, if you have a system with a 40 mil
specified range, its most linear region will be between 10 and 30 mils.
While decreasing the linear measuring range of your system, it will
improve system performance; conversely, increasing measuring range
will degrade performance. Depending upon your measurement
objectives, either can be used.
As you perform a high accuracy band calibration, keep in mind that the
smaller the calibrated span the more interactive the controls will
become. More interaction means more iterations before your system is
fully calibrated.
When the desired span is below 20% of specified linear measuring
range, the additional improvement in linearity is generally not worth the
trouble caused by control interaction.