Calculating Absolute Specification Limits - Fluke 9100 User Handbook Manual

Final Width = 215mm
9-4 Section 9: Verifying the Model 9100 Accuracy Specification
9.6

Calculating Absolute Specification Limits

For each chosen verification point it will be necessary to calculate absolute measurement
limits which can be used to judge whether or not the 9100 is performing within its
specification. As mentioned earlier, the accuracy specifications detailed in Section 7 of
this handbook are absolute accuracies which incorporate all the uncertainties involved in
calibrating the 9100 up to and including those of National Standards.
If verification results are to be at all meaningful, the measuring equipment which is used
to verify the 9100's accuracy must have separate traceability to the same National
Standards, and the uncertainties involved in this traceability must be taken into account
when determining the absolute verification limits required at the chosen verification
points.
To ensure that worst-case conditions are taken into account, these verification limits
should be calculated as follows (an example is given alongside each step to aid
understanding):-
1. By referring to the appropriate function table in Section
7 of this manual, locate the 9100 output band in which
the required verification point is located. Note the
accuracy of the 9100 in this band, which is given in the
form of a fraction of output value plus a floor (offset)
value.
2. Multiply the verification point value by the fraction of
Output figure in the specification.
3. Add the Floor figure in the specification to the result
obtained in step (2), taking into account any 'engineering
-6
unit' multiplier such as (x10 ), m (x10
in the Floor value. This will give you a combined
Fraction of Output + Floor uncertainty specification
for the 9100 at the verification point value.
4. Add the result obtained in step (3) to the verification
point value to obtain a 'high' output limit for the 9100
output.
5. Subtract the result obtained in step (3) from the
verification point value to obtain a 'low' output limit for
the 9100 output.
Example: For a verification
point value of 2V, the 9100
accuracy specification is:-
0.006% + 41.6 V
2 x 0.006 = 0.00012
100
0.00012 + 41.6x10
= 0.0001616
-3
) etc. specified
2 + 0.0001616
= 2.0001616
2 - 0.0001616
= 1.9998384
-6