National Instruments NI PXIe-4139 User Manual

• Allow a warm-up time of at least 30 minutes after the chassis is powered on and
NI-DCPower is loaded and recognizes the PXIe-4139. The warm-up time ensures that the
PXIe-4139 and test instrumentation are at a stable operating temperature.
• Use shielded copper wire for all cable connections to the device. Use twisted-pair wire to
eliminate noise and thermal offsets.
• To ensure the system has had adequate time to settle, wait one second after requesting a
new current or voltage or after changing a load before taking a measurement.
• Keep relative humidity between 10% and 70%, noncondensing.
• When making measurements, configure the following aperture time-related settings:
– Set the niDCPower Aperture Time property or
NIDCPOWER_ATTR_APERTURE_TIME attribute to 2 power-line cycles (PLCs) on
the device.
– Set the niDCPower Aperture Time Units property or
NIDCPOWER_ATTR_APERTURE_TIME_UNITS to power line cycles.
– Set the niDCPower Configure Power Line Frequency property or the
NIDCPOWER_ATTR_POWER_LINE_FREQUENCY attribute to either 50 or 60
depending on the frequency of the AC power line in your location.
• Do not use the NI-DCPower Soft Front Panel (SFP) to request test points for any
adjustment functions because you cannot set aperture time using the SFP.
• Ensure that properties or attributes for the device that are not specified in calibration
procedures are set to their default values.
• When making measurements, configure any specified digital multimeters (DMMs) with
the best available ranges and measurement settings for each specified test point.
• For verification procedures, maintain an ambient temperature of 23 °C ±5 °C. Maintain
an internal device temperature range of T
cal
±1 °C.
1
• For adjustment procedures, maintain an ambient temperature of 23 °C ±1 °C. The
PXIe-4139 internal temperature is greater than the ambient temperature.
As-Found and As-Left Limits
The as-found limits are the published specifications for the device. NI uses these limits to
determine whether the device meets the device specifications when it is received for
calibration.
The as-left limits are equal to the published NI specifications for the device, less guard bands
for measurement uncertainty, temperature drift, and drift over time. NI uses these limits to
determine whether the device will meet the device specifications over its calibration interval.
1
T
cal
is the internal device temperature recorded by the PXIe-4139 at the completion of the last self-
calibration. Call the niDCPower Get Self Cal Last Temp VI to query T
cal
from the PXIe-4139.
4 | ni.com | NI PXIe-4139 Calibration Procedure

National Instruments NI PXIe-4139 Specifications

General

Brand	National Instruments
Model	NI PXIe-4139
Category	Measuring Instruments
Language	English