refer to the
Maintain Forced-Air Cooling Note to Users
document available at
.
•
Allow a warm-up time of at least 30 minutes after the chassis is powered on and
NI-DCPower is loaded and recognizes the NI 4141. The warm-up time ensures that the
NI 4141 and test instrumentation are at a stable operating temperature.
•
Use shielded copper wire for all cable connections to the module. 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.
•
Recalculate the test limits if they differ from the newest device specifications. Test limits
in this document are based on the July 2013 edition of the
NI PXIe-4141 Specifications
.
•
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 module.
–
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 module 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 levels and limits for each specified test point.
•
Disconnect any input signals and perform ACAL ALL function on Keysight 3458A every
24 hours or when the multimeter's temperature changes by ±1 °C from when it was last
externally calibrated or from the last autocal. Use the TEMP? command for the current
internal temperature and compare it to the calibration temperature from executing the
command CAL? 59 for DCV and CAL? 60 for OHMS.
•
Configure Keysight 3458A to 7 ½ digits of resolution and 10 NPLC.
Temperature conditions specific to verification procedures:
•
Maintain an ambient temperature of 23 °C ±5 °C. Maintain an internal device
temperature range of T
cal
±1 °C.
2
2
T
cal
is the internal device temperature recorded by the NI 4141 at the completion of the last self-
calibration. Call the niDCPower Get Self Cal Last Temp VI to query T
cal
from the NI 4141.
4
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NI PXIe-4141 Calibration Procedure
