Service manual

Measurement
Uncertainty
For the performance verification tests in this manual, measurement
uncertainties are calculated based on the Agilent 3458A Digital Multimeter.
The measurement uncertainty shown in Table 2-1 is the accuracy of the
Agilent 3458A using 90-day specifications. The calculations follow.
Closed Channel
Resistance Test
Conditions:
• 4-wire ohms function, 10 Ω range
• 90-day specifications
• Worst-case reading = 2.0 Ω
M.U. = (15 ppm of Reading + 5 ppm of Range)
= (15x10
-6
* 2.0) + ( 5x10
-6
* 10) Ω
= 8.0x10
-5
Ω
DC Isolation Test Conditions:
• 2-wire ohms function, 1 G Ω range
• 90-day specifications
• Worst-case reading = 1.2 G Ω (highest resistance that can be measured
with the Agilent 3458A)
M.U. = (0.5% of Reading + 10ppm of Range)
= (0.005 * 1.2x10
9
) + ( 10x10
-6
* 1x10
9
) Ω
= 6.1x10
6
Ω
Test Accuracy
Ratio (TAR)
Test Accuracy Ratios are not defined for single-sided measurements, so all
measurements have "NA" (Not Applicable) in the TAR column.
32 Verification Tests Chapter 2