National Instruments PXIe-4468 Manual

PXIe-4468

September 2022
PXIe-4468
Calibration procedure

ni.com/services
PXIe-4468 Calibration Procedure

PXIe-4468 Calibration Procedure
2ni.com/services
This document contains the verification and adjustment procedures for the
PXIe-4468 with either BNC or mini-XLR connectors. Use the procedures in this
document to automate calibration or to conduct manual calibration. Review
and become familiar with the entire procedure before beginning the
calibration process.
Contents
Terms and Definitions...............................................................................................3
Calibration Overview.................................................................................................4
Calibration Condition Guidelines .........................................................................5
Calibration Resources...............................................................................................5
Required Software.................................................................................................5
Recommended Documentation...........................................................................6
Test Equipment .....................................................................................................6
Warm Up the DUT......................................................................................................8
Perform Self-Calibration.......................................................................................8
Perform Verification..................................................................................................9
AI Offset Accuracy Verification..............................................................................9
AI Gain Accuracy Verification ..............................................................................12
AI Gain Flatness Verification ...............................................................................14
IEPE Current Verification.....................................................................................17
AO Differential Offset Accuracy Verification.......................................................19
AO Differential Gain Accuracy Verification.........................................................22
AO Gain Flatness Verification..............................................................................26
AO Common-Mode Gain and Offset Verification ...............................................29
Timebase Frequency Accuracy Verification.......................................................31
Perform Adjustment................................................................................................34
AI/AO Gain and Offset Adjustment .....................................................................34
Timebase Adjustment .........................................................................................35
Perform Reverification............................................................................................36
Update the Onboard Calibration Information.......................................................37
Revision History.......................................................................................................37
NI Services ...............................................................................................................38

PXIe-4468 Calibration Procedure
© National Instruments Corporation 3
Terms and Definitions
DUT DUT is an acronym for Device Under Test and refers to the NI product
being calibrated. For this procedure, DUT refers to the PXIe-4468.
As-Found Limits These limits are derived from the published specifications for the DUT.
NI uses these limits to determine if the DUT is performing within the
recommended calibration interval specifications at the time of
calibration and before any adjustment is performed.
As-Left Limits These limits are derived from the published specifications for the DUT
minus guardband to ensure a high probability that the DUT will meet its
specifications over the next recommended calibration interval.
Functional Test Functional Tests determine whether the DUT is operating correctly.
Functional tests are not directly related to performance specifications.
Verification Verification evaluates the measured calibration results against the
defined As-Found Limits. The result of the evaluation is expressed as a
Pass/Fail condition in the calibration certificate using an established
evaluation formula.
Adjustment Adjustment performs a set of operations on the DUT to optimize the
measurement performance and conform it to the assigned calibrated
values.
Reverification Reverification evaluates the measured calibration results against the
As-Left limits after adjustment. The As-Left limits may be tighter than
the As-Found limits.
Recommended
Calibration Interval
This interval indicates the recommended period between each round of
verification and adjustment of the DUT. There is a high probability that,
within this interval, the DUT will remain within the published warranted
performance specifications. Some measurement DUTs have warranted
specifications for different calibration intervals, for example: 24 hours,
90 days, 1 year, and 2 years. In this case, the specification depends on
the calibration cycle chosen by the user.

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Calibration Overview
Recommended Calibration Interval
2 years
Password
NI
Note
This is the default password for all password-protected operations.
This password is site-specific.
Task Estimated Test
Time
Operator
Connections Test Points
Setup 10 minutes — —
Warm Up 15 minutes — —
Verify, Adjust, and
Reverify
19 minutes 36 344
Verify Only 8 minutes 17 171
Adjust Only 3 minutes 2 2
Note
Estimated test times assume the user is conducting a manual
calibration. For most procedures, automating the calibration
significantly reduces test times.
Environmental Conditions Verification Adjustment
Ambient temperature 23 °C ± 5 °C 23 °C ± 5 °C
Internal DUT temperature range Tcal ±5 °C Tcal ±5 °C
Relative humidity Between 20% and 80%, noncondensing

PXIe-4468 Calibration Procedure
© National Instruments Corporation 5
Calibration Condition Guidelines
Keep cabling as short as possible. Long cables act as antennas, picking
up extra noise that can affect measurements.
Ensure that all connections to the DUT are secure.
Allow adequate warm up time for all components of the calibration
system.
Make all connections as shown in diagrams.
Use shielded copper wire for all cable connections to the DUT.
Use twisted-pair wires to eliminate noise and thermal offsets.
Ensure that the PXI/PXI Express chassis fan speed is set to HIGH, that the
fan filters are clean, and that the empty slots contain filler panels. For
more information, refer to the Maintain Forced-Air Cooling Note to Users
document available at ni.com/manuals.
If a DUT fails reverification after adjustment, ensure that the Test
Conditions have been met before returning the DUT to NI.
If the coupling changes from DC to AC (for example, on the first gain
verification point tested), commit the configuration using the DAQmx
Control Task VI and wait 5 seconds for the input to settle. Subsequent
gain verification points, which do not change the coupling, do not
require a delay.
Calibration Resources
Required Software
Note
Ensure that the most recent version of the required driver software is
installed before conducting the calibration.

PXIe-4468 Calibration Procedure
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Install the following software on the calibration system:
DAQmx
Recommended Documentation
Go to ni.com/docs to locate the following documentation for more
information when performing this calibration:
PXIe-4468 Getting Started Guide
PXIe-4468 Specifications
NI-DAQmx Readme
NI-DAQmx Help
LabVIEW Help
NI-DAQmx C Reference Help
NI-DAQmx .NET Help Support for Visual Studio
Test Equipment
This section details the equipment NI recommends for each test performed
as part of this calibration procedure.
NI Calibration Executive Users
Refer to the Calibration Executive Help to find an updated list of test
equipment for this calibration procedure.

PXIe-4468 Calibration Procedure
© National Instruments Corporation 7
Standard Recommended
Model Where Used Functional Requirement(s)
Calibrator Fluke 5730A AI Gain
AI Flatness
Frequency Range:
40 Hz to 100 kHz
Voltage Range: up to
6.3 Vrms
Digital Multimeter
(DMM)
Keysight (Agilent)
3458A
AO Differential Offset
AO Differential Offset
and Gain Adjustment
DC Voltage
Input Range: 100mV,
1 V, 10 V
AO Differential Gain
AO Differential
Flatness
AC Voltage
Input Range: 1 Vrms,
10 Vrms
Frequency Range:
20Hz to 100 kHz
Function Generator Keysight (Agilent)
33250A series
Timebase Frequency Frequency Range: up
to 90 kHz
PXI Express Chassis NI PXIe-1082
NI PXIe-1085
NI PXIe-1075
NI PXIe-1065
NI PXIe-1062Q
All Tests
System Controller NI PXIe-8135 All Tests A PXI Express
controller or MXI
Express Card
mXLR (F) to BNC (M)
Cable (quantity 1)
NI 140150-0R46 All Tests (mXLR
Variant)
Length: ≤ 0.5m
BNC (M) to BNC (M)
Cable (quantity 1)
Pomona Electronics
5697
All Tests (BNC
Variant)
Length: ≤ 0.5m
BNC (F) to Banana
Adapter (quantity 1)
Pomona Electronics
1269
AI Gain
AI Flatness
AO Offset
AO Gain
AO Flatness
AO Offset and Gain
Adjustment

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Banana to Banana
Cable (quantity 1)
Pomona Electronics
B-4-2
AO Differential Gain
and Offset
Length: ≤ 0.5m
Banana to Alligator
Clip Cable (quantity 2)
Pomona Electronics
1166-12-0 (Black)
1166-12-2 (Red)
AO Differential Gain
and Offset
Length: ≤ 0.5m
Warm Up the DUT
Warm up time starts after the installed DUT is powered on in the chassis.
Warm up time resets after the DUT is removed from the chassis. This DUT
requires 15 minutes to warm up prior to conducting any tests.
Note
Observe adequate Warm up time for all components of the calibration
system.
Perform Self-Calibration
Self-calibration should be performed after the DUT has warmed up for the
recommended time period. This function measures the onboard reference
voltage of the DUT and adjusts the self-calibration constants to account for
any errors caused by short-term fluctuations in the environment.
Complete the following steps to conduct self-calibration using Measurement
& Automation Explorer (MAX).
Note
Disconnect all external signals before beginning self-calibration.
1. Launch MAX.
2. Select My System»Devices and Interfaces»NI PXIe-4468.
3. Start self-calibration using one of the following methods:
4. Click Self-Calibrate in the upper right corner of MAX.