APPENDIX A. EXPLANATION OF EXPERIMENTAL DATA
A-2
TABLE A-1. Accuracies at
Measurement Ranges
90% of all
range
measurements
rms error
0 to 10%
±
2%
±
1%
10 to 20%
±
3%
±
1.5%
20 to 30%
±
5%
±
2.2%
30 to 50%
±
6%
±
3%
*At least ninety percent of all experimental data
fall within these error bands at the noted range
divisions.
The above accuracy is a static accuracy derived
at slow changing conditions with experimental
data. In rapidly changing conditions (e.g., in the
beginning of a rain event) the rate of response
for each wood dowel differs. After sufficient
time to equilibrate, the dowels will come to the
same water content. This difference in rate of
response is inherent in the traditional weighing
fuel stick racks. The effects are lessened by
the additional sorting of the dowels performed at
the factory. Readings above 50% are caused
by surface water on the probe or other external
factors. Readings are mathematically limited to
70%.
The sensor error is the sum of three influences:
1.
Error due to the variability and non-
reproducibility of the response
characteristics of the wood: density,
sorption characteristics, resin content, etc.
2.
Error due to the aging of the wood
(cracking, discoloration, mass loss as resin
evaporates). This effect is not a factor for
new sticks.
3.
Offset error due to the electronic circuitry
interchangeability, this error is negligible
over 10% fuel moisture.
