NI 5421/5441 Calibration Procedure
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© National Instruments
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7
Test Conditions
Follow these guidelines to optimize the connections and the environment during calibration:
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Keep connections to the NI 5421/5441 short. Long cables and wires act as antennas,
picking up extra noise that can affect measurements.
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Keep relative humidity below 80%.
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Maintain a temperature between 18 °C and 28 °C.
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Observe the 15 minute warm-up time.
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Allow the DMM to warm up for its recommended warm up interval.
System Setup
Before you begin the calibration procedure, connect the Reference Clock output from your
counter to the CLK IN connector on your DUT (device under test).
Calibration Procedures
The complete calibration procedure consists of self-calibrating, verifying the performance of the
NI 5421/5441, adjusting the calibration constants, and re-verifying performance after the
adjustments. In some cases, the complete calibration procedure may not be required. Refer to the
section for more information.
The external calibration procedure automatically stores the calibration date to allow traceability.
Verifying NI 5421/5441 Specifications
Note
Always self-calibrate the NI 5421/5441 before beginning a verification
procedure.
This section provides instructions for verifying the NI 5421/5441 specifications. This section
also includes instructions for updating the calibration cycle.
You can verify the following specifications for the NI 5421/5441:
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Oscillator frequency accuracy
•
DC gain and offset accuracy
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AC accuracy
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Flatness
Note
If any of these tests fail immediately after you perform an external
adjustment, verify that you have met the required test conditions before you return
the NI 5421/5441 to NI for repair.
