National Instruments 6738 Manual

CALIBRATION PROCEDURE
NI 6738/6739
Analog Output Devices and Modules with NI-DAQmx
This document contains the verification and adjustment procedures for the National Instruments
PCIe-6738 and PXIe-6738/6739 analog output devices and modules. For more information
about calibration solutions, visit ni.com/calibration.
Contents
Software.................................................................................................................................... 1
Documentation.......................................................................................................................... 2
Password................................................................................................................................... 2
Test Equipment......................................................................................................................... 3
Test Conditions......................................................................................................................... 4
Calibration Procedure ............................................................................................................... 4
Initial Setup............................................................................................................................... 5
Self-Calibration ................................................................................................................5
Checking Device Temperature Changes .......................................................................... 6
Verification ............................................................................................................................... 7
Analog Output Verification .............................................................................................. 7
Counter Verification ......................................................................................................... 11
Adjustment................................................................................................................................ 12
EEPROM Update ..................................................................................................................... 14
Reverification ........................................................................................................................... 14
Test Limits ................................................................................................................................ 15
Worldwide Support and Services ............................................................................................. 16
Software
Calibrating NI 6738/6739 devices and modules requires the installation of NI-DAQmx on the
calibration system. You must use NI-DAQmx 17.6 or later. Refer to the NI-DAQmx Readme to
ensure support for the device you want to calibrate. You can download NI-DAQmx from
ni.com/downloads. NI-DAQmx supports many programming languages, including
LabVIEW, LabWindows™/CVI™, C/C++, C#, and Visual Basic .NET. When you install
NI-DAQmx, you need to only install support for the application software that you intend to use.

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Documentation
Consult the following documents for information about your NI 6738/6739, NI-DAQmx, and
your application software. All documents are available on ni.com, and help files install with
the software.
Password
The default password for password-protected operations is NI.
The DAQ Getting Started Guide for your device or module
These guides provide instructions for installing the NI 6738/6739 with
NI-DAQmx.
NI 6738/6739 User Manual
The user manual provides information about your NI 6738/6739 device.
Your 673x Device Specifications
The specifications document for your DAQ device provides detailed specifications,
including the device calibration interval.
NI-DAQmx Readme
Operating system and application software support in NI-DAQmx.
NI-DAQmx Help
Information about creating applications that use the NI-DAQmx driver.
LabVIEW Help
LabVIEW programming concepts and reference information about NI-DAQmx
VIs and functions.
NI-DAQmx C Reference Help
Reference information for NI-DAQmx C functions and NI-DAQmx C properties.
NI-DAQmx .NET Help Support for Visual Studio
Reference information for NI-DAQmx .NET methods and NI-DAQmx .NET
properties, key concepts, and a C enum to .NET enum mapping table.

NI 6738/6739 Calibration Procedure |© National Instruments |3
Test Equipment
Table 1 lists the equipment recommended for the performance verification and adjustment
procedures. If the recommended equipment is not available, select a substitute using the
requirements listed in Table 1.
Caution For compliance with Electromagnetic Compatibility (EMC)
requirements, this product must be operated with shielded cables and accessories.
If unshielded cables or accessories are used, the EMC specifications are no longer
guaranteed unless all unshielded cables and/or accessories are installed in a shielded
enclosure with properly designed and shielded input/output ports.
Table 1. Recommended Equipment
Equipment
Recommended
Models Where Used Requirements
DMM NI 4070*Analog Output
Verification
and
Adjustment
If this instrument is unavailable,
use a multiranging 6 1/2-digit
DMM with an accuracy of 40 ppm
or better.
Counter Agilent 53220A Counter
Verification
Whether using the recommended
instrument or another counter, you
must ensure that it is configured to
be at least 12.5 ppm (0.00125%)
accurate.
PXI Express
chassis
NI PXIe-1062Q —Use with NI PXIe-6738/6739
modules.
Shielded
DAQ cable
NI SHC68-68-A2 —Use with NI 6738/6739 modules.
NI SH68-C68-S —Use when connecting signals using
the NI 6738 Adapter or NI 6739
Adapter.
DAQ
accessory
NI SCB-68,
NI SCB-68A
—Shielded I/O connector block
with 68 screw terminals for
easy signal connection to the
NI 6738/6739.
NI CB-68LP,
NI CB-68LPR,
NI TBX-68
—Low-cost termination accessories
with 68 screw terminals for easy
connection of field I/O signals to
the NI 6738/6739.
*If you are using the NI 4070, ensure that it is set to the 10 V range.

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Test Conditions
Follow these guidelines to optimize the connections and the environment during calibration.
• Keep connections to the device as short as possible. Long cables and wires can act as
antennae, which could pick up extra noise that would affect measurements.
• Verify that all connections to the NI 6738/6739 are secure.
• Use shielded copper wire for all cable connections to the device. Use twisted-pair wire to
eliminate noise and thermal offsets.
• Maintain an ambient temperature of 23 °C ± 5 °C throughout the Analog Output
Verification procedure. The device temperature is greater than the ambient temperature.
Refer to the Calibration Procedure section for more information about calibration
temperatures and temperature drift.
• For valid test limits, maintain the device temperature within ±1 °C from the last
self-calibration and ±10 °C from the last external calibration.
• Keep relative humidity below 80%.
• Allow adequate warm-up time of at least 15 minutes to ensure that the measurement
circuitry is at a stable operating temperature.
Calibration Procedure
The calibration process has the following steps.
1. Initial Setup—Configure your device in NI-DAQmx, adjust the self-calibration constants
of the device, and verify that the current device temperature does not cause you to
incorrectly calibrate your device.
2. Verification—Verify the existing operation of the device. This step allows you to confirm
that the device was operating within its specified range prior to calibration.
3. Adjustment—Perform an external calibration that adjusts the device calibration constants
with respect to a known voltage source.
4. EEPROM Update—When an adjustment procedure is completed, the NI 6738/6739
internal calibration memory (EEPROM) is immediately updated. If you do not want to
perform an adjustment, you can update the calibration date without making any
adjustments.
5. Reverification—Perform another verification to ensure that the device is operating within
its specifications after adjustment.
These steps are described in detail in the following sections.

NI 6738/6739 Calibration Procedure |© National Instruments |5
Initial Setup
Refer to your device getting started guide for information about how to install the software and
hardware and how to configure the device in Measurement & Automation Explorer (MAX).
Note When a device is configured in MAX, it is assigned a device name. Each
function call uses this device name to determine which device to calibrate. This
document uses Dev_name to refer to the device name. In the following procedures,
use the device name as it appears in MAX.
Complete the following steps to set up the NI 6738/6739.
1. Install the application software (if applicable).
2. Install the NI-DAQmx driver software.
3. Power off the chassis that will contain the device and install the device.
4. Power on the chassis and launch MAX.
5. Select My System»Devices and Interfaces»your device.
6. Configure the device identifier and select Self-Test to ensure that the device is working
properly.
Self-Calibration
Complete the following steps to self-calibrate the device.
Note Disconnect all external signals before beginning self-calibration.
1. Wait for the device to warm-up for at least 15 minutes.
2. Launch MAX.
3. Select My System»Devices and Interfaces»your device.
4. Click Self-Calibrate.

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Checking Device Temperature Changes
Device temperature changes greater than those described in the Test Conditions section will
require action to ensure that your calibration is successful. Complete the following steps to check
for device temperature changes:
1. Self-calibrate your device as described in the Self-Calibration section.
2. Call DAQmxGetCalDevTemp with the following parameter:
•deviceName: Dev_name
3. Call DAQmxGetSelfCalLastTemp with the following parameter:
•deviceName: Dev_name
If the current device temperature differs by more than 1 °C from the last self-calibration
temperature, or you cannot maintain a device temperature within 1 °C of the last
self-calibration temperature throughout the verification process, the calibration limits for
the devices that support self-calibration are not valid.
In order to successfully calibrate your device in this case:
• Allow the device temperature to settle and self-calibrate your device again.
• Change the test limits to include the additional error due to temperature drift. Refer to
your device specifications document for more information.
4. Call DAQmxGetExtCalLastTemp with the following parameter:
•deviceName: Dev_name
If the current device temperature differs by more than 10 °C from the last external
calibration temperature, or you cannot maintain a device temperature within 10 °C of the
last external calibration temperature throughout the verification process, the calibration
limits are not valid.
In order to successfully calibrate your device in this case:
• Change the system so that the temperature is within ±10 °C of the temperature
recorded during the last external calibration.
• Change the test limits to include the additional error due to temperature drift. Refer to
your device specifications document for more information.
Note You also can read the current device temperature, the temperature during the
last self-calibration, and the temperature during the last external calibration in MAX.
Launch MAX, select My System»Devices and Interfaces»your device, and then
click the Calibration tab. Temperature information is displayed Self-Calibration and
External Calibration sections of the Settings tab.

NI 6738/6739 Calibration Procedure |© National Instruments |7
Verification
The following performance verification procedures describe the sequence of operation and
provide test points required to verify the NI 6738/6739. The verification procedures assume that
adequate traceable uncertainties are available for the calibration references.
The verification procedure is divided into the major functions of the device. Throughout the
verification process, use the tables in the Test Limits section to determine if your device needs
to be adjusted. These tables show all acceptable settings for the device.
Analog Output Verification
The NI 6738 has 32 analog outputs, AO <0..31>. The NI 6739 has 64 analog outputs, AO <0..63>.
Note Table 3, NI 6738/6739 Analog Output Values, is based upon the most recent
edition of the specifications document for your device. Refer to the most recent
specifications document online at ni.com/manuals.
Note The test limits used in this document assume a maximum temperature drift of
±10 °C from the last external calibration, and a maximum temperature drift of ±1 °C
from the last self-calibration. Refer to the Checking Device Temperature Changes
section for more information and instructions on reading your device temperature and
comparing it against the device temperature during the last external calibration.
Caution Do not perform analog output verification and counter verification
simultaneously, as the multiple signal connections will produce noise that can affect
measurements.
Complete the following steps to check analog output measurements.
1. Connect your DMM to AO 0 as shown in Table 2, Analog Output Connections.
Note If you are using the NI 4070, ensure that it is set to the 10 V range.
Table 2. Analog Output Connections
Analog
Output*
DMM
Positive Input Negative Input
AO 0 Connector 0, AO 0 (pin 10) Connector 0, AO GND 0/1 (pin 11)
AO 1 Connector 0, AO 1 (pin 44) Connector 0, AO GND 0/1 (pin 11)
AO 2 Connector 0, AO 2 (pin 45) Connector 0, AO GND 2/3 (pin 39)
AO 3 Connector 0, AO 3 (pin 12) Connector 0, AO GND 2/3 (pin 39)
AO 4 Connector 0, AO 4 (pin 13) Connector 0, AO GND 4/5 (pin 41)

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AO 5 Connector 0, AO 5 (pin 47) Connector 0, AO GND 4/5 (pin 41)
AO 6 Connector 0, AO 6 (pin 48) Connector 0, AO GND 6/7 (pin 49)
AO 7 Connector 0, AO 7 (pin 15) Connector 0, AO GND 6/7 (pin 49)
AO 8 Connector 0, AO 8 (pin 16) Connector 0, AO GND 8/9/10 (pin 50)
AO 9 Connector 0, AO 9 (pin 17) Connector 0, AO GND 8/9/10 (pin 50)
AO 10 Connector 0, AO 10 (pin 51) Connector 0, AO GND 8/9/10 (pin 50)
AO 11 Connector 0, AO 11 (pin 52) Connector 0, AO GND 11 (pin 18)
AO 12 Connector 0, AO 12 (pin 53) Connector 0, AO GND 12/13 (pin 20)
AO 13 Connector 0, AO 13 (pin 54) Connector 0, AO GND 12/13 (pin 20)
AO 14 Connector 0, AO 14 (pin 21) Connector 0, AO GND 14/15 (pin 55)
AO 15 Connector 0, AO 15 (pin 22) Connector 0, AO GND 14/15 (pin 55)
AO 16 Connector 0, AO 16 (pin 23) Connector 0, AO GND 16/17 (pin 24)
AO 17 Connector 0, AO 17 (pin 57) Connector 0, AO GND 16/17(pin 24)
AO 18 Connector 0, AO 18 (pin 58) Connector 0, AO GND 18/19 (pin 59)
AO 19 Connector 0, AO 19 (pin 25) Connector 0, AO GND 18/19 (pin 59)
AO 20 Connector 0, AO 20 (pin 26) Connector 0, AO GND 20/21 (pin 27)
AO 21 Connector 0, AO 21 (pin 60) Connector 0, AO GND 20/21 (pin 27)
AO 22 Connector 0, AO 22 (pin 61) Connector 0, AO GND 22/23 (pin 62)
AO 23 Connector 0, AO 23 (pin 28) Connector 0, AO GND 22/23 (pin 62)
AO 24 Connector 0, AO 24 (pin 29) Connector 0, AO GND 24/25 (pin 30)
AO 25 Connector 0, AO 25 (pin 63) Connector 0, AO GND 24/25 (pin 30)
AO 26 Connector 0, AO 26 (pin 64) Connector 0, AO GND 26/27 (pin 65)
AO 27 Connector 0, AO 27 (pin 31) Connector 0, AO GND 26/27 (pin 65)
AO 28 Connector 0, AO 28 (pin 32) Connector 0, AO GND 28/29 (pin 33)
AO 29 Connector 0, AO 29 (pin 66) Connector 0, AO GND 28/29 (pin 33)
AO 30 Connector 0, AO 30 (pin 67) Connector 0, AO GND 30/31 (pin 68)
Table 2. Analog Output Connections (Continued)
Analog
Output*
DMM
Positive Input Negative Input

NI 6738/6739 Calibration Procedure |© National Instruments |9
AO 31 Connector 0, AO 31 (pin 34) Connector 0, AO GND 30/31 (pin 68)
AO 32 Connector 1, AO 32 (pin 10) Connector 1, AO GND 32/33 (pin 11)
AO 33 Connector 1, AO 33 (pin 44) Connector 1, AO GND 32/33 (pin 11)
AO 34 Connector 1, AO 34 (pin 45) Connector 1, AO GND 34/35 (pin 46)
AO 35 Connector 1, AO 35 (pin 12) Connector 1, AO GND 34/35 (pin 46)
AO 36 Connector 1, AO 36 (pin 13) Connector 1, AO GND 36/37 (pin 14)
AO 37 Connector 1, AO 37 (pin 47) Connector 1, AO GND 36/37 (pin 14)
AO 38 Connector 1, AO 38 (pin 48) Connector 1, AO GND 38/39 (pin 49)
AO 39 Connector 1, AO 39 (pin 15) Connector 1, AO GND 38/39 (pin 49)
AO 40 Connector 1, AO 40 (pin 16) Connector 1, AO GND 40/41/42 (pin 50)
AO 41 Connector 1, AO 41 (pin 17) Connector 1, AO GND 40/41/42 (pin 50)
AO 42 Connector 1, AO 42 (pin 51) Connector 1, AO GND 40/41/42 (pin 50)
AO 43 Connector 1, AO 43 (pin 52) Connector 1, AO GND 43 (pin 18)
AO 44 Connector 1, AO 44 (pin 53) Connector 1, AO GND 44/45 (pin 20)
AO 45 Connector 1, AO 45 (pin 54) Connector 1, AO GND 44/45 (pin 20)
AO 46 Connector 1, AO 46 (pin 21) Connector 1, AO GND 46/47 (pin 55)
AO 47 Connector 1, AO 47 (pin 22) Connector 1, AO GND 46/47 (pin 55)
AO 48 Connector 1, AO 48 (pin 23) Connector 1, AO GND 48/49 (pin 24)
AO 49 Connector 1, AO 49 (pin 57) Connector 1, AO GND 48/49 (pin 24)
AO 50 Connector 1, AO 50 (pin 58) Connector 1, AO GND 50/51 (pin 59)
AO 51 Connector 1, AO 51 (pin 25) Connector 1, AO GND 50/51 (pin 59)
AO 52 Connector 1, AO 52 (pin 26) Connector 1, AO GND 52/53 (pin 27)
AO 53 Connector 1, AO 53 (pin 60) Connector 1, AO GND 52/53 (pin 27)
AO 54 Connector 1, AO 54 (pin 61) Connector 1, AO GND 54/55 (pin 62)
AO 55 Connector 1, AO 55 (pin 28) Connector 1, AO GND 54/55 (pin 62)
AO 56 Connector 1, AO 56 (pin 29) Connector 1, AO GND 56/57 (pin 30)
Table 2. Analog Output Connections (Continued)
Analog
Output*
DMM
Positive Input Negative Input

10 |ni.com |NI 6738/6739 Calibration Procedure
2. Measure the internal device temperature and perform self-calibration if necessary. Refer to
the Checking Device Temperature Changes section for more information.
3. Call DAQmxCreateTask with the following parameters:
•taskName:
MyAOVoltageTask
•taskHandle: &taskHandle
4. Call DAQmxCreateAOVoltageChan with the following parameters.
•taskHandle: taskHandle
•physicalChannel: Dev_name/ao0
•nameToAssignToChannel: AOVoltageChannel
•minVal: -10.0
•maxVal: 10.0
•units: DAQmx_Val_Volts
•customScaleName: NULL
5. Call DAQmxStartTask with the following parameter:
•taskHandle: taskHandle
6. Call DAQmxWriteAnalogF64 with the following parameters, using a Test Point from
Table 3, NI 6738/6739 Analog Output Values.
•taskHandle: taskHandle
•numSampsPerChan: 1
•autoStart: 1
•timeout: 10.0
•dataLayout: DAQmx_Val_GroupByChannel
•writeArray: &data
AO 57 Connector 1, AO 57 (pin 63) Connector 1, AO GND 56/57 (pin 30)
AO 58 Connector 1, AO 58 (pin 64) Connector 1, AO GND 58/59 (pin 65)
AO 59 Connector 1, AO 59 (pin 31) Connector 1, AO GND 58/59 (pin 65)
AO 60 Connector 1, AO 60 (pin 32) Connector 1, AO GND 60/61 (pin 33)
AO 61 Connector 1, AO 61 (pin 66) Connector 1, AO GND 60/61 (pin 33)
AO 62 Connector 1, AO 62 (pin 67) Connector 1, AO GND 62/63 (pin 68)
AO 63 Connector 1, AO 63 (pin 34) Connector 1, AO GND 62/63 (pin 68)
*Connector 1/AO <32..63> are on the PXIe-6739 only.
Table 2. Analog Output Connections (Continued)
Analog
Output*
DMM
Positive Input Negative Input