*TB 43-177
APPENDIX B
PROCEDURE FOR REDUCTION OF DATA FOR
SURVEILLANCE AND CALIBRATION OF STANDARD CELLS
(obs-D)-(tc). Corr-D for observations 9 through 16 =
B-1.
General.
Data produced as a result of
(obs-D) + (tc).
measurements for the APSL (Reference: Appendix A of
f.
P = Left-right component (residual EMF),
this technical bulletin) is reduced by computer at the
calculated from the summation of the observed
APSL. When surveillance measurements are made in
differences divided by the number of observations.
the in terms of the CRC Volt, manual reduction of data is
required. This appendix provides the method to be used
P = Σobs-D
for this manual data reduction and will provide the same
level of accuracy as the computer program if care is
16
g. ∆Vp = The EMF difference between computed
taken that no errors enter the manual computations.
However, in of the higher probability of errors involved in
values of the cell at left and the at right.
manual computations, the method should be
programmed into local computers, if available, to
∆Vp = EMFL - EMFR
eliminate as much as possible human-error component.
h. DEV. = The deviation of
the
observed
difference from the predicted difference.
B-2.
A single run containing 16 observations in a
measurement design and computed (calculated) as
DEV = (corr-D) - (∆Vp) - (P)
instructed herein provides information on:
i.
Sx = The observed standard
deviation of a
a. The EMF of each cell used in the design
single observation.
relative to the mean of the reference group.
b. The left-right component (the residual EMFs of
Sx = Σ(DEV)
2
the measuring system).
N-M
c. The deviation of each observation from the
predicted value.
Where N = number of observations, and
d. The standard deviation of a single observation.
number of cells. For two groups of 4 cells, N = 16 and M
= 8 resulting in N - M = 8.
B-3.
Definitions
of
terms
used
for
manual
calculations:
B-4.
The certified mean voltage (Vref) of the
reference standard cell group must be known use the
a. Vref = Mean voltage of reference group.
computed values of the individual of the working and
b. Vx = Mean voltage of working group.
reference groups will terms of the reference mean and
c. tc = Temperature EMF correction for reference
the observed differences. The nominal temperature and
and working enclosures.
measured temperature at time of test for both the
d. Obs-D = Observed difference.
reference and working enclosure is also required. The
e. Corr-D = Corrected differences, calculated
measurement equation for cells of the working group
from the observed difference value and temperature
appears as follows:
EMF correction. Corr -D for observations 1 through 8 =
B-1
