STAT TEST
Erratic readings or readings that seem to fluctuate may indicate a
problem with the gauge. If the readings are suspect, the
stat test
or
statistical stability test
may be performed by an operator to validate
the normal operation of the gauge.
A stat test consists of twenty 1-minute counts. From the twenty
counts, the standard deviation is calculated. This standard deviation
is compared to a theoretical standard deviation value. Ideally, this
ratio should be one. However, the 4640-B pre-scales (or divides) the
counts by 8, resulting in an ideal ratio of (0.35). The acceptable
limits for the ratios are from (0.25) to (0.45). The gauge is
considered unstable if the ratios are outside these limits for two out
of three stat tests.
6.
S
P
E
C
IA
L
F
U
N
C
T
IO
N
S
To execute a stat test, press
〈
SHIFT
〉
and
〈
SPECIAL
〉
.
Either press
〈
YES
〉
once then
〈
START/ENTER
〉
, or press
〈
3
〉
for
the display:
Place Gauge on
Spacer & both on
Block,Put Rod in
SAFE,Press ENTER
Place the gauge on the air gap spacer with the handle end resting
over the two posts (on the bottom of the fixture). Place the gauge
and spacer on the 1-inch magnesium reference block. Place the
source rod in the
SAFE
position. To start taking the twenty counts
press
〈
START/ENTER
〉
.
After the twenty counts have been completed, the gauge will display
the average counts and indicate if the test passed or failed. The
individual count data may be viewed or printed at this time. Figure
6–3 shows a sample printout of the stat test data.
Model 4640-B
6–5
Содержание 4640-B
Страница 6: ...NOTES vi...
Страница 12: ...NOTES xii...
Страница 17: ...1 GENERAL INFORMATION Figure 1 1 Model 4640 B Parts and Accessories Model 4640 B 1 5...
Страница 22: ...NOTES 1 10...
Страница 26: ...NOTES 2 4...
Страница 84: ...NOTES Appendix A 12...
Страница 108: ...NOTES Appendix C 18...
Страница 130: ...NOTES Appendix F 8...
