User manual

Section 14: Verification Series 3700 System Switch/Multimeter Reference Manual
14-4 3700S-901-01 Rev. C / July 2008
Verification limits
The verification limits stated in this section have been calculated using only the
Series 3700 one-year accuracy specifications, and they do not include test
equipment uncertainty. If a particular measurement falls outside the allowable
range, recalculate new limits based both on the Series 3700 specifications and
corresponding test equipment specifications.
Example reading limit calculation
The following is an example of how reading limits have been calculated. Assume
you are testing the 10V DC range using a 10V input value. Using the Series
3700 one-year accuracy specification for 10V DC of ± (25ppm of reading +
2ppm of range), the calculated limits are:
Reading limits = 10V ± [(10V × 25ppm) + (10V × 2ppm)]
Reading limits = 10V ± (0.00025 + 0.00002)
Reading limits = 10V ± 0.00027V
Reading limits = 9.99973V to 10.00027V
Calculating resistance reading limits
Resistance reading limits must be recalculated based on the actual calibration
resistance values supplied by the equipment manufacturer. Calculations are
performed in the same manner as shown in the preceding example, using the
actual calibration resistance values instead of the nominal values in the example
when performing your calculations.
For example, assume that you are testing the 10k range using an actual
10.03k calibration resistance value. Using Series 3700 one-year 10k range
accuracy of (60ppm of reading + 4ppm of range), the calculated reading limits
are:
Reading limits = 10.03k [(10.03k x 60ppm) + (10.03k x 6ppm)]
Reading limits = 10.03k [(0.000618) + (0.0000618)]
Reading limits = 10.03k ± 0.0006798
Reading limits = 10.0293202k to 10.0306798k