User's Manual

NI 4070/4072 Calibration Procedure 6 ni.com

• Clean any oxidation from the banana plugs on the Fluke 5440 cables

before plugging them into the binding posts of the calibrator or the

banana plug connectors of the NI 4070/4072. Oxidation tarnishes the

copper banana plugs so that they appear dull rather than shiny and

leads to greater thermal EMF.

• Keep the blue banana plugs on the Fluke 5440 cables connected to the

V GUARD binding post of the calibrator at all times.

• Prevent the cables from moving or vibrating by taping or strapping

them to a nonvibrating surface. Movement or vibration causes

triboelectric effects that can result in measurement errors.

Calibration Procedures

The calibration process includes the following steps:

1. Initial Setup—Set up the test equipment.

2. Verification Procedures—Verify the existing operation of the device.

This step confirms whether the device is operating within its specified

range prior to calibration. Figure 4 shows the procedural flow for

verification.

3. Adjustment Procedures—Submit the device to NI for a factory

calibration to adjust the calibration constants. Figure 5 shows the

procedural flow for adjustment.

4. Reverification—Repeat the verification procedure to ensure that the

device is operating within its specifications after adjustment.

These steps are described in more detail in the following sections.

Note In some cases, the complete calibration procedure may not be required. Refer to

Appendix A: Calibration Options for more information.

Initial Setup

Note This section is necessary for pre-adjustment verifications only. If you are performing

a post-adjustment verification, skip the setup and go directly to the Verifying DC Voltage

section.

To set up the test equipment, complete the following steps:

1. Remove all connections from the four input banana plug connectors on

the NI 4070/4072.

2. Verify that the calibrator has been calibrated within the time limits

specified in the Required Test Equipment section, and that DC zeros

calibration has been performed within the last 30 days. Consult the