Fluke 5720A Calibration Requirements, When to Adjust the Calibrator’s Uncertainty Specifications

Calibration and Verification 3

Calibrating the 5700A/5720A Series II to External Standards

3-7. Calibration Requirements

Both the calibrator and the recommended external standards have the ability to internally control (or compensate for) ambient temperature variations. Therefore it is unnecessary to keep the calibrator in tightly controlled temperatures during calibration. During the calibration procedure, the calibrator prompts you to enter the ambient temperature, and includes this information in specification readouts and output shift reports.

3-8. When to Adjust the Calibrator’s Uncertainty Specifications

Table 3-1 lists each external standard’s uncertainty limit, and the 5700A/5720A Series II uncertainty specifications that must adjusted accordingly if that limit is exceeded.

As long as the external standards have the uncertainties listed in Table 3-1, you do not need to adjust the calibrator’s absolute uncertainty specifications in Chapter 1. However, if your standard’s uncertainty exceeds the value in the table you must adjust some of the calibrator’s absolute uncertainty specifications by the algebraic difference between your standard’s uncertainty and the uncertainty limit listed in the Table 3-1. For example, if the dc voltage standard has an uncertainty of ±2.5 ppm, then the 5700A and the 5720A absolute uncertainty specifications listed in Table 3-1 for the traceable quantity of voltage must all be increased by ±1 ppm.

Table 3-1. Standards for Calibrating 5700A/5720A Series II

Fluke

Standard

732B

742A-1

742A-10k

Traceable

Quantity

Voltage

Resistance

Resistance

Nominal	Uncertainty
Value	Limit
10V	±1.5 ppm
1Ω	±10 ppm
10 kΩ	±4 ppm

5700A/5720A Series II

Specifications susceptible to

Uncertainty Limit

dc volts, ac volts,

dc current, ac current

1Ω, 1.9Ω

ac current, dc current 10Ω to 100 MΩ

3-7