As Left Stability; Guard Bands - Fluke 9190A Operator's Manual

9190A
Operators Manual

As Left Stability

Take stability data at the temperatures listed in Table 4-9. Compare the results to the
specification. The data can be taken after the accuracy data is taken in As Left Accuracy
for each of the temperatures listed in Table 4-9.
SETPOINT °C
140 °C
0 °C
−95 °C

Guard Bands

Guard bands are used to make sure the UUT is calibrated to a level better than the actual
specification. This compensates for any drift that can occur over the calibration interval.
If drift does occur, the unit would still be in specification. The guard bands can be applied
differently to the As Found specification and the As Left specification. Typically the As
Left guard band is tighter than the As Found guard band. Guard band limits are
determined by the user and are decided by criteria such as:
• Calibration interval
• Environmental conditions
• Unit performance
4-14
Table 4-9. As Left Stability Specifications
2σ Spec (±°C)
0.015 °C
0.015 °C
0.015 °C
Soak time min Duration min
45
45
45
30
30
30