Fluke 9118A User Manual page 76

9118A
Users Manual
Stability Test
The 7 steps that follow find the As Found and As Left
data for stability.
3. Push  to start the furnace.
4. Put the test thermocouple (TC1) at the center of
the furnace (zero reference).
5. Stabilization time starts after one hour when the
stability indicator shows the furnace temperature is
stable.
6. After the stabilization time, record the temperature
on the readout for TC1 at 1 minute intervals for
30 minutes.
7. Calculate 2σ (2 times the standard deviation) of
the 30 recorded measurements.
8. Compare the calculated 2σ with the value in the
stability column of Table 8.
66
Table 8. Stability Test Data
Setpoint Stabilization
(°C) Time (min)
300 60
700 60
1000 60
1200 60
If the test fails, do steps 6 through 8 again. If it fails a
second time, repair the instability.
9. Record the result.
Axial Uniformity
The steps that follow make up the axial uniformity test and
the formulae to calculate the SKEW and ZONE parameter
values. The new values are put into the Product to correct
for axial temperature gradients.
The axial uniformity test must be done before the
axial uniformity adjustment.
10. Move test thermocouple TC2 to one of the positions
shown in Table 9.
11. Let the thermocouple soak for a minimum of 5 minutes
at this position.
12. Record the temperature for TC1 and TC2 in Table 9.
Stability 2σ Limit
Samples
(±°C)
30 0.2
30 0.2
30 0.2
30 0.2
Note