National Instruments NI 5421 Manual

CALIBRATION PROCEDURE
NI 5421/5441
Contents
Conventions ............................................................................................ 2
Introduction............................................................................................. 3
Software and Documentation Requirements........................................... 3
Software ........................................................................................... 3
Documentation................................................................................. 5
Self-Calibration Procedures .................................................................... 5
MAX ................................................................................................ 5
FGEN Soft Front Panel.................................................................... 6
NI-FGEN ......................................................................................... 6
External Calibration Options .................................................................. 7
Complete Calibration....................................................................... 8
Optional Calibration ........................................................................ 9
External Calibration Requirements......................................................... 11
Test Equipment ................................................................................ 11
Test Conditions ................................................................................ 11
External Calibration Procedures ............................................................. 12
Writing Your Calibration Procedure................................................ 12
Calibration Procedures in LabVIEW........................................ 12
Calibration Procedures in LabWindows/CVI........................... 12
Calibration Procedures in C...................................................... 12
Verifying NI 5421/5441 Specifications........................................... 13
Verifying the Oscillator Frequency Accuracy.......................... 15
Verifying the DC Gain and Offset Accuracy ........................... 18
Verifying the Main Analog Path Gain............................... 18
Verifying the Main Analog Path Offset ............................ 23
Verifying the Gain of the Direct Path ............................... 26
Adjusting the NI 5421/5441 ............................................................ 29
Initializing the External Calibration Session ............................ 32

NI 5421/5441 Calibration Procedure 2 ni.com
Adjusting the Analog Output ....................................................32
Initializing Analog Output Calibration .............................. 32
Adjusting the Main Path Pre-Amplifier Offset .................. 34
Adjusting the Main Path Pre-Amplifier Gain .................... 38
Adjusting the Main Path Post-Amplifier
Gain and Offset............................................................... 42
Adjusting the Direct Path Gain .........................................45
Adjusting the Oscillator Frequency...........................................49
Adjusting the Calibration ADC.................................................52
Closing the External Adjustment Session .................................57
Calibration Utilities .................................................................................58
MAX.................................................................................................58
FGEN SFP........................................................................................58
NI-FGEN ..........................................................................................59
Where to Go for Support .........................................................................60
Conventions
The following conventions are used in this manual:
»The »symbol leads you through nested menu items and dialog box options
to a final action. The sequence File»Page Setup»Options directs you to
pull down the File menu, select the Page Setup item, and select Options
from the last dialog box.
This icon denotes a note, which alerts you to important information.
This icon denotes a caution, which advises you of precautions to take to
avoid injury, data loss, or a system crash. When this symbol is marked on
a product, refer to the Safety and Radio-Frequency Interference Read Me
First for information about precautions to take.
bold Bold text denotes items that you must select or click in the software, such
as menu items and dialog box options. Bold text also denotes parameter
names.
italic Italic text denotes variables, emphasis, a cross reference, or an introduction
to a key concept. This font also denotes text that is a placeholder for a word
or value that you must supply.
monospace Text in this font denotes text or characters that you should enter from the
keyboard, sections of code, programming examples, and syntax examples.
This font is also used for the proper names of disk drives, paths, directories,
programs, subprograms, subroutines, device names, functions, operations,
variables, filenames, and extensions.

©National Instruments Corporation 3 NI 5421/5441 Calibration Procedure
Introduction
This document contains instructions for calibrating the NI 5421/5441
arbitrary waveform generator. This calibration procedure is intended for
metrology labs. It describes specific programming steps for writing an
external calibration procedure for the NI 5421/5441.
Refer to ni.com/calibration for additioan information about
calibration solutions from National Instruments.
Software and Documentation Requirements
This section describes the software and documentation required for both
self-calibration and external calibration.
Software
Calibrating the NI 5421 requires installing NI-FGEN version 2.0 or later on
the calibration system. Calibrating the NI 5441 requires installing
NI-FGEN version 2.3 or later on the calibration system. You can download
NI-FGEN from the Instrument Driver Network at ni.com/idnet.
NI-FGEN supports programming the Self-Calibration Procedures and the
External Calibration Procedures in the LabVIEW, LabWindows™/CVI™,
and C application development environments (ADEs). When you install
NI-FGEN, you only need to install support for the ADE that you intend to
use.
For LabWindows/CVI, the NI-FGEN function panel (niFgen.fp)
provides help about the functions available. LabVIEW support is in the
niFgen.llb file, and all calibration functions appear in the function
palette.

NI 5421/5441 Calibration Procedure 4 ni.com
Calibration functions are C function calls or LabVIEW VIs in NI-FGEN.
In this document, the C function call is shown first, followed by the
corresponding LabVIEW VI, or NI-FGEN LabVIEW property node,
in parentheses. The C function calls are valid for any compiler capable of
calling a 32-bit DLL. Many of the functions use constants defined in the
niFgen.h file. To use these constants in C, you must include niFgen.h
in your code when you write the calibration procedure. Refer to Table 1
for file locations.
The calibration process is described in the Self-Calibration Procedures and
the External Calibration Procedures sections, including step-by-step
instructions on calling the appropriate calibration functions.
Table 1. Calibration File Locations
File Name and Location Description
IVI\Bin\niFgen_32.dll The NI-FGEN library, which provides the
functionality for calibrating the
NI 5421/5441.
IVI\Lib\msc\niFgen.lib
IVI\Lib\bc\niFgen.lib
Allows you to create applications that call
functions in the niFgen_32.dll:
• For Microsoft Visual C/C++, link to
msc\niFgen.lib.
• For LabWindows/CVI, link to the library
appropriate to your current compatibility
mode (msc for Microsoft Visual C/C++).
IVI\Include\niFgen.h A header file for the accessible functions in
the niFgen_32.dll. You must include this
file in any C code that you write to call these
functions.
<LabVIEW>\instr.lib\niFgen\niFgen.llb
(LabVIEW)
Contains VIs that correspond to the functions
in the niFgen_32.dll.
IVI\Drivers\niFgen\niFgen.fpl
(CVI)
Contains the function panels for the functions
in the niFgen_32.dll.

©National Instruments Corporation 5 NI 5421/5441 Calibration Procedure
Documentation
For information about NI-FGEN and the NI 5421/5441, you may find the
following documents helpful:
•NI Signal Generators Getting Started Guide
•NI Signal Generators Help
•NI 5421/5441 Specifications
•NI-FGEN Instrument Driver Quick Reference Guide
The NI Signal Generators Getting Started Guide provides instructions for
installing and configuring NI signal generators.
The NI Signal Generators Help includes detailed information about
the NI 5421/5441 and the NI-FGEN functions. You can access this help file
by selecting Start»Programs»National Instruments»NI-FGEN»
Documentation»NI Signal Generators Help. For the latest versions
of NI documentation, refer to ni.com/manuals.
Self-Calibration Procedures
The NI 5421/5441 is capable of performing self-calibration, which adjusts
the gain and offset of the main and direct analog paths. Self-calibration uses
only an onboard ADC to measure the output voltage. You can implement
self-calibration on the NI 5421/5441 by following procedures similar to the
Verifying the DC Gain and Offset Accuracy and the Adjusting the Analog
Output procedures. However, output impedance, oscillator frequency, and
the calibration ADC cannot be adjusted during self-calibration.
You can initiate self-calibration interactively from Measurement &
Automation Explorer (MAX) or from the FGEN Soft Front Panel (SFP).
Alternatively, you can initiate self-calibration programmatically using
NI-FGEN.
MAX
To initiate self-calibration from MAX, complete the following steps:
1. Launch MAX.
2. Select My System»Devices and Interfaces»NI-DAQmx Devices.

NI 5421/5441 Calibration Procedure 6 ni.com
3. Select the device that you want to calibrate.
4. Initiate self-calibration in one of the following ways:
•ClickSelf-Calibrate in the upper right corner.
• Right-click the device name under Devices and Interfaces,
and select Self-Calibrate from the drop-down menu.
FGEN Soft Front Panel
To initiate self-calibration from the FGEN SFP, complete the following
steps:
1. Select the device that you want to calibrate using the Device
Configuration dialog box (Edit»Device Configuration).
2. Open the Calibration dialog box (Utility»Calibration).
3. Click Perform self-calibration.
NI-FGEN
To self-calibrate the NI 5421/5441 programmatically using NI-FGEN,
complete the following steps:
1. Call niFgen_init (niFgen Initialize VI) to open an NI-FGEN session
using the following parameters:
•resourceName: The name of the device that you want to calibrate.
You can find this name under Devices and Interfaces in MAX.
•IDQuery: VI_TRUE
•resetDevice: VI_TRUE
•vi: A pointer to a ViSession. The variable passed by reference
through this parameter receives the value that identifies the
session created by this function. This value acts as the session
handle and is passed as the first parameter to all subsequent
NI-FGEN functions.
2. Call niFgen_SelfCal (niFgen Self Cal VI) using the following
parameter:
•vi: The session handle returned from niFgen_init
3. Call niFgen_close (niFgen Close VI) to close the NI-FGEN session
using the following parameter:
•vi: The session handle returned from niFgen_init

©National Instruments Corporation 7 NI 5421/5441 Calibration Procedure
External Calibration Options
External calibration involves both verification and adjustment. Verification
is the process of testing the device to ensure that the output accuracy is
within certain specifications. You can use verification to ensure that the
adjustment process was successful or to determine if the adjustment
process needs to be performed.
Adjustment is the process of measuring and compensating for device
performance to improve the output accuracy. Performing an adjustment
updates the calibration date, resetting the calibration interval. The device is
guaranteed to meet or exceed its published specifications for the duration
of the calibration interval.
This document provides two sets of test limits for most verification stages,
the calibration test limits and the published specifications. The calibration
test limits are more restrictive than the published specifications. If all of
the output errors determined during verification fall within the calibration
test limits, the device is guaranteed to meet or exceed its published
specifications for a full calibration interval (two years). For this reason,
you must verify against the calibration test limits when performing
verification after adjustment.
If all of the output errors determined during verification fall within the
published specifications, but not within the calibration test limits, the
device meets its published specifications. However, the device may not
remain within these specifications for another two years. The device will
meet published specifications for the rest of the current calibration interval.
In this case, you can perform an adjustment if you want to improve
the output accuracy or reset the calibration interval. If some output
errors determined during verification do not fall within the published
specifications, you must perform an adjustment to restore the device
operation to its published specifications.
The Complete Calibration section describes the recommended
calibration procedure. The Optional Calibration section describes
alternative procedures that allow you to skip adjustment if the device
already meets its calibration test limits or published specifications.

NI 5421/5441 Calibration Procedure 8 ni.com
Complete Calibration
Performing a complete calibration is the recommended way to guarantee
that the NI 5421/5441 meets or exceeds its published specifications for a
two-year calibration interval. At the end of the complete calibration
procedure, you verify that the output error falls within the calibration test
limits. Figure 1 shows the programming flow for complete calibration.
Figure 1. Complete Calibration Programming Flow
Adjust
(Cal Dates and
Temperatures
Updated)
Verify
Document
Post-Adjustment
Results
Meets
Calibration
Test Limits?
Review
Verification/
Adjustment
Procedure or
Return Device
Verify
Self-Calibrate
Calibration/
Verification
Complete
Ye s N o
Document
Pre-Adjustment
Results

©National Instruments Corporation 9 NI 5421/5441 Calibration Procedure
Optional Calibration
You can choose to skip the adjustment steps of the calibration procedure
if the output error is within the calibration test limits or the published
specifications during the first verification. If all of the output errors
determined during the first verification fall within the calibration test
limits, the device is guaranteed to meet or exceed its published
specifications for a full calibration interval. In this case, you can update
the calibration date, effectively resetting the calibration interval, without
actually performing an adjustment. Refer to the Adjusting the NI 5421/5441
section for more information.
If all of the output errors determined during the first verification fall within
the published specifications, but not within the calibration test limits,
adjustment is also optional. However, you cannot update the calibration
date because the device will not necessarily operate within the published
specifications for an additional two years.
Note Regardless of the results of the first verification, if you choose to perform an
adjustment you must verify that the output error falls within the calibration test limits
at the end of the calibration procedure.
Figure 2 shows the programming flow for the optional calibration.

NI 5421/5441 Calibration Procedure 10 ni.com
Figure 2. Optional Calibration Programming Flow
Self-Calibrate
Verify
Document
Pre-Adjustment
Results
Meets
Calibration
Test Limits?
Meets
Published
Specifications?
Update Calibration
Dates and
Temperatures
Without Adjusting
Results
Within
Published Specs
(Adjustment
Optional)
Adjust
Anyway?
Adjust
(Cal Dates and
Temperatures
Updated)
Verify Document
Post-Adjustment
Results
Meets
Calibration
Test Limits?
Calibration/
Verification
Complete
Review
Verification/
Adjustment
Procedure or
Return Device
Ye s N o
Ye s N o
Ye s No
Ye sNo

©National Instruments Corporation 11 NI 5421/5441 Calibration Procedure
External Calibration Requirements
This section describes the test equipment and test conditions required for
calibration.
Test Equipment
External calibration requires different equipment for each applicable
specification. Refer to Table 2 for a list of equipment.
Test Conditions
Follow these guidelines to optimize the connections and the environment
during calibration:
• Keep connections to the NI 5421/5441 short.
• Keep relative humidity below 80%.
• Maintain a temperature between 18 °C and 28 °C.
• Observe the 15-minute warm-up time.
Table 2. Equipment Required for Calibrating the NI 5421/5441
Instrument
Applicable
Specification
Minimum
Specifications
Recommended
Instrument
Digital multimeter
(DMM)
DC gain and offset DC accuracy ≤±50 ppm
Resolution ≤1 µV
NI PXI-4070
Agilent/HP 34401A
Keithley 2000
Male banana to
female BNC adapter
— —
Male BNC to
female SMB cable
50 Ω, RG-223 —
Spectrum analyzer or
frequency meter
Frequency accuracy Ability to measure
10 MHz or higher
sine waves
Frequency accuracy
to ±500 ppb
NI PXI-5660
Agilent/HP 8560E
Agilent/HP 53131A
or HP 53132A
with timebase option
001, 010, or 012
Male BNC to
female SMB cable
50 Ω, RG-223 —

NI 5421/5441 Calibration Procedure 12 ni.com
External Calibration Procedures
The complete external calibration procedure consists of self-calibrating,
verifying the performance of the NI 5421/5441, adjusting the calibration
constants, and verifying again after the adjustments. In some cases, the
complete calibration procedure may not be required. Refer to the External
Calibration Options section for more information.
The external calibration procedure automatically stores the calibration date
to allow traceability.
Writing Your Calibration Procedure
Before you begin to write your calibration program, review the
programming flows in Figures 1 and 2.
Calibration Procedures in LabVIEW
To write calibration procedures in LabVIEW, you must use the
VIs included in the niFgen.llb file. After installation, these VIs
appear within the NI-FGEN Calibration palette under Functions»
Instrument I/O»Instrument Drivers»NI-FGEN»Calibration.
Calibration Procedures in LabWindows/CVI
To write calibration procedures in LabWindows/CVI, you must use the
functions included in the niFgen.fp file. After installation, you can locate
the calibration functions under the Calibration class node.
Calibration Procedures in C
To write calibration procedures in C, you must include the niFgen.h
file in the code that calls the calibration functions, and you must link
the niFgen.lib file into the build of your executable.

©National Instruments Corporation 13 NI 5421/5441 Calibration Procedure
Verifying NI 5421/5441 Specifications
Note Always self-calibrate the NI 5421/5441 before beginning a verification procedure.
This section provides instructions for verifying the NI 5421/5441
specifications. This section also includes instructions for updating the
calibration cycle.
Verification determines whether the device is performing within its
specifications prior to external adjustment. Verification and external
adjustment together comprise a complete calibration. To verify that the
NI 5421/5441 still meets its specifications, you must use NI-FGEN to
control the NI 5421/5441.
The steps in the verification procedures describe the code that you use to
generate the appropriate signals, as well as the NI-FGEN function calls
that you make to verify specifications.
You can verify the following specifications for the NI 5421/5441:
• Oscillator frequency accuracy
• DC gain and offset accuracy
The verification procedure for each of these specifications includes setting
up, programming, and cleaning up.
Note If any of these tests fail immediately after you perform an external adjustment, verify
that you have met the required test conditions before you return the NI 5421/5441 to NI for
repair.
Refer to Table 2 for information about which instrument to use for
verifying each specification. Refer to Figure 3 for the names and locations
of the NI PXI-5421/5441 and the NI PCI-5421 front panel connectors.

NI 5421/5441 Calibration Procedure 14 ni.com
Figure 3. NI PXI-5421/5441 and NI PCI-5421 Front Panel Connectors
PFI 0
PFI 1
ACCESS ACTIVE
CLK
IN
CH 0
DIGITAL DATA & CONTROL
CH
0
PFl
0
DIGITAL DATA & CONTROL
NI PCI-5421
CLK
IN
PFl
1

©National Instruments Corporation 15 NI 5421/5441 Calibration Procedure
Verifying the Oscillator Frequency Accuracy
This test verifies the frequency accuracy of the oscillator on the
NI 5421/5441. The verification involves generating a 10 MHz sine wave
with the NI 5421/5441 and measuring the sine wave frequency with one of
the instruments from Table 2.
To verify the frequency accuracy of the oscillator on the NI 5421/5441,
complete the following steps:
1. Connect the NI 5421/5441 CH 0 front panel connector to the
instrument measuring the frequency accuracy with a male BNC to
female SMB cable.
2. Call niFgen_init (niFgen Initialize VI) using the following
parameters:
•resourceName: The name of the device that you want to verify.
You can find this name under Devices and Interfaces in MAX.
•IDQuery: VI_TRUE
•resetDevice: VI_TRUE
•vi: A pointer to a ViSession. The variable passed by reference
through this parameter receives the value that identifies the
session created by this function. This value acts as the session
handle and is passed as the first parameter to all subsequent
NI-FGEN functions.
3. Call niFgen_SetAttributeViReal64 to set the sample rate
(niFgen property node: Arbitrary Waveform Output»Sample Rate)
using the following parameters:
•vi: The session handle returned from niFgen_init
•channelName: "0"
•attributeID: NIFGEN_ATTR_ARB_SAMPLE_RATE
•value: 100000000
4. Call niFgen_SetAttributeViReal64 to set the gain (niFgen
property node: Arbitrary Waveform Output»Arbitrary Waveform
Gain) using the following parameters:
•vi: The session handle returned from niFgen_init
•channelName: "0"
•attributeID: NIFGEN_ATTR_ARB_GAIN
•value: 1
Note You can adjust the gain value based on which measuring device you use.

NI 5421/5441 Calibration Procedure 16 ni.com
5. Call niFgen_SetAttributeViReal64 to set the offset (niFgen
property node: Arbitrary Waveform Output»Arbitrary Waveform
Offset) using the following parameters:
•vi: The session handle returned from niFgen_init
•channelName: "0"
•attributeID: NIFGEN_ATTR_ARB_OFFSET
•value: 0
Note You can adjust the offset value based on which measuring device you use.
6. Call niFgen_SetAttributeViBoolean to set the analog filter state
(niFgen property node: Output Attributes»Analog Filter Enabled)
using the following parameters:
•vi: The session handle returned from niFgen_init
•channelName: "0"
•attributeID: NIFGEN_ATTR_ANALOG_FILTER_ENABLED
•value: VI_TRUE
7. Call niFgen_SetAttributeViBoolean to set the digital filter state
(niFgen property node: Output Attributes»Digital Filter Enabled)
using the following parameters:
•vi: The session handle returned from niFgen_init
•channelName: "0"
•attributeID: NIFGEN_ATTR_DIGITAL_FILTER_ENABLED
•value: VI_TRUE
8. Call niFgen_SetAttributeViReal64 to set the digital filter
interpolation factor (niFgen property node: Output Attributes»
Digital Filter Interpolation Factor) using the following parameters:
•vi: The session handle returned from niFgen_init
•channelName: "0"
•attributeID:
NIFGEN_ATTR_DIGITAL_FILTER_INTERPOLATION_FACTOR
•value: 4
9. Generate an array of waveform samples. Each waveform should have
10 samples per cycle with a total of 500 samples and 50 sine wave
cycles. Because you set the sample rate to 100 MS/s and because you
are using 10 samples per cycle, the resulting waveform is a 10 MHz
sine wave.
Note The sample values of this waveform must fall between –1.0 and 1.0.

©National Instruments Corporation 17 NI 5421/5441 Calibration Procedure
10. Call niFgen_CreateArbWaveform (niFgen Create Arbitrary
Waveform VI) using the following parameters:
•vi: The session handle returned from niFgen_init
•wfmSize: The size in samples (500) of the waveform you created
in step 9
•wfmData: The array of waveform samples that you created in
step 9
•wfmHandle: The variable passed by reference through this
parameter receives the value (waveform handle) that identifies
the waveform created by this function.
11. Call niFgen_InitiateGeneration (niFgen Initiate Generation VI)
to initiate the waveform generation using the following parameter:
•vi: The session handle returned from niFgen_init
12. Measure the frequency out of the NI 5421/5441.
A frequency error of 45 Hz for a 10 MHz signal corresponds to an
error of 4.5 ppm. This limit accounts for the initial accuracy and the
frequency deviation caused by temperature and aging. Refer to Table 3
for frequency ranges.
13. Call niFgen_AbortGeneration (niFgen Abort Generation VI) to
abort the waveform generation using the following parameter:
•vi: The session handle returned from niFgen_init
14. Call niFgen_close (niFgen Close VI) to close the instrument
driver session, to destroy the instrument driver session and all of
its properties, and to release any memory resources NI-FGEN uses.
Use the following parameter:
•vi: The session handle returned from niFgen_init
Table 3. Frequency Ranges
Calibration Test Limit Published Specifications ±25 ppm
Low High Low High
9,999,955 Hz 10,000,045 Hz 9,999,750 Hz 10,000,250 Hz

NI 5421/5441 Calibration Procedure 18 ni.com
Verifying the DC Gain and Offset Accuracy
This test verifies the DC gain and offset accuracy of the NI 5421/5441 into
a high-impedance load by generating a number of DC voltages and offsets,
measuring the voltage with a DMM, and comparing the NI 5421/5441 to
the error limits.
The DC gain and offset accuracy verification procedure has three
sub-procedures that verify the following:
• Main analog path gain
• Main analog path offset
• Direct path gain
Verifying the Main Analog Path Gain
To verify the gain of the NI 5421/5441 main analog path, complete the
following steps:
1. Connect the NI 5421/5441 CH 0 front panel connector to the DMM for
measuring DC gain and offset accuracy.
2. Call niFgen_init (niFgen Initialize VI) using the following
parameters:
•resourceName: The name of the device that you want to verify.
You can find this name under Devices and Interfaces in MAX.
•IDQuery: VI_TRUE
•resetDevice: VI_TRUE
•vi: A pointer to a ViSession. The variable passed by reference
through this parameter receives the value that identifies the
session created by this function. This value acts as the session
handle and is passed as the first parameter to all subsequent
NI-FGEN functions.
3. Call niFgen_SetAttributeViBoolean to set the analog filter state
(niFgen property node: Output Attributes»Analog Filter Enabled)
using the following parameters:
•vi: The session handle returned from niFgen_init
•channelName: "0"
•attributeID: NIFGEN_ATTR_ANALOG_FILTER_ENABLED
•value: VI_FALSE

©National Instruments Corporation 19 NI 5421/5441 Calibration Procedure
4. Call niFgen_SetAttributeViReal64 to set the load impedance
(niFgen property node: Output Attributes»Load Impedance)
using the following parameters:
•vi: The session handle returned from niFgen_init
•channelName: "0"
•attributeID: NIFGEN_ATTR_LOAD_IMPEDANCE
•value: 10000000000
5. Call niFgen_SetAttributeViInt32 to set the analog path (niFgen
property node: Output Attributes»Analog Path) using the following
parameters:
•vi: The session handle returned from niFgen_init
•channelName: "0"
•attributeID: NIFGEN_ATTR_ANALOG_PATH
•value: NIFGEN_VAL_MAIN_ANALOG_PATH
6. Call niFgen_SetAttributeViReal64 to set the output impedance
(niFgen property node: Basic Operation»Output Impedance) using
the following parameters:
•vi: The session handle returned from niFgen_init
•channelName: "0"
•attributeID: NIFGEN_ATTR_OUTPUT_IMPEDANCE
•value: 50
7. Call niFgen_SetAttributeViBoolean to enable the analog output
(niFgen property node: Basic Operation»Output Enabled) using
the following parameters:
•vi: The session handle returned from niFgen_init
•channelName: "0"
•attributeID: NIFGEN_ATTR_OUTPUT_ENABLED
•value: VI_TRUE
8. Create an array of waveform samples for the positive full-scale DC
waveform. This array should contain 500 samples with each sample
having the value 1.0 (representation: double).

NI 5421/5441 Calibration Procedure 20 ni.com
9. Call niFgen_CreateArbWaveform (niFgen Create Arbitrary
Waveform VI) using the following parameters:
•vi: The session handle returned from niFgen_init
•wfmSize: The size in samples (500) of the waveform you created
in step 8
•wfmData: The array of waveform samples that you created in
step 8
•wfmHandle: The variable passed by reference through this
parameter receives the value (waveform handle) that identifies the
waveform created by this function (positive full-scale handle).
10. Create an array of waveform samples for the negative full-scale DC
waveform. This array should contain 500 samples with each sample
having the value –1.0 (representation: double).
11. Call niFgen_CreateArbWaveform (niFgen Create Arbitrary
Waveform VI) using the following parameters:
•vi: The session handle returned from niFgen_init
•wfmSize: The size in samples (500) of the waveform that you
created in step 10
•wfmData: The array of waveform samples that you created in
step 10
•wfmHandle: The variable passed by reference through this
parameter receives the value (waveform handle) that identifies the
waveform created by this function (negative full-scale handle).
12. Call niFgen_SetAttributeViReal64 to set the offset (niFgen
property node: Arbitrary Waveform Output»Arbitrary Waveform
Offset) using the following parameters:
•vi: The session handle returned from niFgen_init
•channelName: "0"
•attributeID: NIFGEN_ATTR_ARB_OFFSET
•value: 0
Repeat steps 13 through 23 for each of the 24 iterations listed in Table 4,
changing the Gain value for each iteration.