F
R
R
=
−
2
1
delta
AF
BE
DE
CF
=
−
−
T
1-3
- Measured temperature using thermometer.
R
1-3
- Value of R from display of 2200 (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 250.0
°
C
T
3
and
R
3
are the measured temperature and resistance at 450.0
°
C
9.2.2
Compute R
0
& ALPHA:
a
T
delta
T
T
1
1
1
1
100
1
100
=
+
⎡
⎣⎢
⎤
⎦⎥
−
⎡
⎣⎢
⎤
⎦⎥
a
T
delta
T
T
3
3
3
3
100
1
100
=
+
⎡
⎣⎢
⎤
⎦⎥
−
⎡
⎣⎢
⎤
⎦⎥
rzero
R a
R a
a
a
=
−
−
3
1
1
3
1
3
alpha
R
R
R a
R a
=
−
−
1
3
3
1
1
3
delta
is the new value of DELTA computed above
5. Program the new values for DELTA (delta), R
0
(rzero) and ALPHA (alpha)
into the calibrator with the following steps.
1. Press SET and EXIT keys at the same time and then press SET until
R
0
is displayed.
2. Press SET then use the UP or DOWN keys until the correct numerical
setting is displayed. Press SET to accept the new value.
3. Repeat step 2 for ALPHA and DELTA.
2200 Temperature Controller
User’s Guide
42
