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PXIe-4147 Self-Calibration

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    Last Modified: May 12, 2020

    The PXIe-4147 includes a self-calibration feature that you can use to significantly reduce many error sources, such as voltage source and measure offset error, voltage source and measure gain error, and current source and measure offset error.

    When you run self-calibration, the output terminal is disconnected. Low-amplitude, low-energy glitches may appear at the output, but in most circumstances, these glitches are not noticeable. Self-calibration on the PXIe-4147 is typically under 30 seconds.

    Self-Calibrating All Channels in a Single Session

    When calling niDCPower Cal Self Calibrate (niDCPower_CalSelfCalibrate), specify all channels of your PXIe-4147 with the channel name input. You cannot self-calibrate a subset of PXIe-4147 channels.

    When to Self-Calibrate

    For optimum accuracy, use self-calibration in the following situations:

    • After first installing the PXIe-4147 in a chassis
    • After any module that is in the same chassis as the PXIe-4147 is installed, uninstalled, or moved
    • When the PXIe-4147 is in an environment where the ambient temperature changes or the PXIe-4147 temperature has drifted more than ±5 °C from the temperature at the last self-calibration
    • Once 24 hours elapse after a previous self-calibration

    The PXIe-4147 incorporates a temperature sensor that is used to determine when the temperature changes ±5 °C from the previous calibration. When the most recent self-calibration time and temperature are queried using niDCPower Get Self Cal Last Date And Time (niDCPower_GetSelfCalLastDateAndTime) or niDCPower Get Self Cal Last Temp (niDCPower_GetSelfCalLastTemp), the value returned is from the most recent self-calibration, regardless of the Self Calibration Persistence property (NIDCPOWER_ATTR_SELF_CALIBRATION_PERSISTENCE attribute). When the one-year calibration interval expires, an external calibration is required.

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    Note

    Self-calibration is often used as the first step in debugging measurement errors.


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