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NI 4070/4072 Calibration Procedure
6
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•
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.
—Set up the test equipment.
2.
—Verify the existing operation of the device.
This step confirms whether the device is operating within its specified
range prior to calibration. Figure 5 shows the procedural flow for
verification.
3.
—Perform an external adjustment of the device
that adjusts the calibration constants with respect to standards of
known values. Figure 6 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
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 section, and that DC zeros calibration has been
performed within the last 30 days. Consult the Fluke 5700A/5720A
user documentation for instructions on calibrating these devices.