Fluke 9190A - As Left Stability; Guard Bands

9190A
Operators Manual
4-14
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.
Table 4-9. As Left Stability Specifications
SETPOINT °C 2σ Spec (±°C) Soak time min Duration min
140 °C 0.015 °C 45 30
0 °C 0.015 °C 45 30
−95 °C 0.015 °C 45 30
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