Fluke 9140 - Compute R & ALPHA

C
TTTT
=
⎡
⎣
⎢
⎤
⎦
⎥
−
⎡
⎣
⎢
⎤
⎦
⎥
−
⎡
⎣
⎢
⎤
⎦
⎥
−
⎡
⎣
⎢
⎤
⎦
3322
100
1
100 100
1
100
⎥
D
TTTT
=
⎡
⎣
⎢
⎤
⎦
⎥
−
⎡
⎣
⎢
⎤
⎦
⎥
−
⎡
⎣
⎢
⎤
⎦
⎥
−
⎡
⎣
⎢
⎤
⎦
2211
100
1
100 100
1
100
⎥
ERR=−
32
FRR=−
21
delta
AF BE
DE CF
=
−
−
T
1-3
- Measured temperature using thermometer.
R
1-3
- Value of set-point resistance from display of 9140. (Press SET and
DOWN at the same time.)
where
T
1
and R
1
are the measured temperature and resistance at 50.0 °C
T
2
and R
2
are the measured temperature and resistance at 200.0 °C
T
3
and R
3
are the measured temperature and resistance at 350.0 °C
10.2.2 Compute R
0
& ALPHA:
a T delta
TT
11
11
100
1
100
=+
⎡
⎣
⎢
⎤
⎦
⎥
−
⎡
⎣
⎢
⎤
⎦
⎥
a T delta
TT
33
33
100
1
100
=+
⎡
⎣
⎢
⎤
⎦
⎥
−
⎡
⎣
⎢
⎤
⎦
⎥
rzero
Ra Ra
aa
=
−
−
31 13
13
alpha
RR
Ra Ra
=
−
−
13
31 13
delta is the new value of DELTA computed above
5. Program the new values for DELTA (delta), R
0
(rzero) & ALPHA (alpha)
into the dry-well using the following steps.
a. Press the SET and EXIT keys at the same time and then press SET until
R0 is displayed.
9140 Dry-well Calibrator
User’s Guide
44