Calibration Example - Fluke 7080 User Manual

7080/7081 Calibration Bath
User's Guide
11.4
60
The user should keep a record of these values in case they may need to be re-
stored in the future. The new values, R
ing the old values for R
and t , and the temperature errors err
H
⎡
−
err t err t
' =
H L L
R 0 ⎢
−
⎣ t t
H L
⎡
+
( 1 ALPHA t err
' =
ALPHA ⎢
⎣
For example R and ALPHA were previously set for 100.000 and 0.0038500
0
respectively and the data for t
new values R0' and ALPHA' would be computed as 99.885 and 0.0038302 re-
spectively. Program the new values R
the calibration by setting the temperature to t
again. If desired the calibration procedure may be repeated again to further im-
prove the accuracy.

Calibration Example

The bath is to be used between 25 and 75°C and it is desired to calibrate the
bath as accurately as possible for operation within this range. The current val-
ues for R0 and ALPHA are 100.000 and 0.0038500 respectively. The calibra-
tion points are chosen to be 30.00 and 80.00°C. The measured bath
' and ALPHA', are computed by enter-
0
and ALPHA, the calibration temperature set-points t
0
and err
L
⎤
+
H
ALPHA 1 ⎥ R 0
⎦
− +
) ( 1 ALPHA t err
H L
−
t t
H L
, t , err , and err
L H L
and ALPHA into the controller. Check
0
into the following equations.
H
⎤
)
+
L H
1 ⎥ ALPHA
⎦
were as given above, then the
H
and t and measuring the errors
L H
L