Service manual

Performance Test Record
Table 2-2, "Performance Test Record," is a form you may copy and use to
record performance verification test results for the multiplexers. Table 2-2
shows multiplexer test limits, DMM measurement uncertainty, and test
accuracy ratio (TAR) values.
Test Limits Test limits are defined for relay closed channel resistance and DC isolation
using the specifications in the individual module’s User’s Manual. The relay
contact resistance and DC isolation specifications are single-ended, meaning
that there is an upper limit OR a lower limit, but not both. In Table 2-2, the
Minimum or Maximum column is blank for a single-sided test.
Measurement
Uncertainty
For the performance verification tests in this manual, measurement
uncertainties are calculated based on the 3458A Digital Multimeter.
The measurement uncertainty shown in Table 2-2 is the accuracy of the
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)
= (15×10
−6
⋅ 2.0 + 5×10
−6
⋅ 10) (Ω)
= 8.0×10
−5
Ω__________
DC Isolation Test Conditions:
• 2-wire ohms function, 1 GΩ range
• 90-day specifications
• Worst-case reading = 1.2 GΩ (highest resistance that can
be measured with the 3458A)
M.U. = (0.5% of Reading + 10ppm of Range)
=
(0.005 ⋅ 1.2×10
9
+ 10×10
−6
⋅ 1×10
9
) (Ω)
= 6.0×10
6
Ω_________
Test Accuracy Ratio
(TAR)
Test Accuracy Ratios (TAR) are not defined for single-sided measurements,
so all closed-channel resistance and DC isolation measurements show NA
(Not Applicable) in the TAR column.
Chapter 2 Verification Tests 37