National Instruments NI PXI-5922 User manual

CALIBRATION PROCEDURE
NI PXI/PCI-5922
Flexible-resolution Oscilloscope
This document contains instructions for writing an external calibration procedure for the
NI PXI/PCI-5922 (NI 5922) flexible-resolution oscilloscope. This calibration procedure is
intended for metrology labs. For more information about calibration solutions,
visit ni.com/calibration.
Contents
Introduction .............................................................................................................................. 2
Self-Calibration ................................................................................................................2
External Calibration.......................................................................................................... 2
Calibration Intervals ......................................................................................................... 2
Software and Documentation ........................................................................................... 2
Documentation.......................................................................................................................... 4
Self-Calibration Procedures...................................................................................................... 4
MAX................................................................................................................................. 5
Scope SFP......................................................................................................................... 5
NI-SCOPE ........................................................................................................................5
External Calibration Options ....................................................................................................6
Complete Calibration........................................................................................................ 7
Optional Calibration ......................................................................................................... 7
External Calibration Requirements .......................................................................................... 9
Test Equipment................................................................................................................. 9
Test Conditions.................................................................................................................9
External Calibration Procedures............................................................................................... 10
Verifying NI 5922 Specifications..................................................................................... 10
Vertical Offset Accuracy .......................................................................................... 10
Noise......................................................................................................................... 11
Input Bias Current .................................................................................................... 13
Vertical Gain Accuracy ............................................................................................ 15
Timing Accuracy ...................................................................................................... 17
Adjusting the NI 5922 ...................................................................................................... 18
Calibration Utilities .................................................................................................................. 20
MAX................................................................................................................................. 20
NI-SCOPE ........................................................................................................................20
Where to Go for Support .......................................................................................................... 21

2|ni.com |NI 5922 Calibration Procedure
Introduction
The NI 5922 supports two types of calibration: self-calibration (or internal calibration) and
external calibration.
Self-Calibration
Self-calibration, also known as internal calibration, uses a software command and requires no
external connections. Self-calibration improves measurement accuracy by compensating for
variables such as temperature that may have changed since the last external calibration.
Self-calibration retains the traceability of the external calibration.
External Calibration
External calibration is generally performed with a high-precision oscilloscope calibrator at
either NI or a metrology lab. The external calibration procedure replaces all calibration constants
in the EEPROM and is equivalent to a factory calibration at NI. Because the external calibration
procedure changes all EEPROM constants, it invalidates the original calibration certificate. If an
external calibration is done with a traceable signal generator source, a new calibration certificate
can be issued.
Calibration Intervals
Self-calibration can be performed as necessary to compensate for environmental changes.
Caution Although you can use self-calibration repeatedly, self-calibrating the
NI 5922 more than a few times a day may cause excessive wear on the relays
over time.
The measurement accuracy requirements of your application determine how often you should
externally calibrate the NI 5922. NI recommends that you perform a complete external
calibration at least once every two years. You can shorten this interval based on the accuracy
demands of your application or the requirements of your processes. Refer to the External
Calibration Options section for more information.
Software and Documentation
Calibrating the NI 5922 requires installing NI-SCOPE version 2.8 or later on the calibration
system. You can download NI-SCOPE from ni.com/downloads. NI-SCOPE supports
programming the self-calibration procedures in a number of programming languages. However,
only LabVIEW and C are supported for the external calibration procedures.
NI-SCOPE 2.8 or later includes all the functions and attributes necessary for calibrating the
NI 5922. For LabWindows™/CVI™, the NI-SCOPE function panel, niScopeCalfp, provides
further help on the functions available in CVI. LabVIEW support is installed in
niScopeCal.llb, and all calibration functions appear in the function palette. Refer to Table 1
for file locations.

NI 5922 Calibration Procedure |© National Instruments |3
Calibration functions are C function calls or LabVIEW VIs in NI-SCOPE. In this document, the
C function call is shown first, followed by the corresponding LabVIEW VI 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 niScopeCal.h file. To use these constants in C, you
must include niScopeCal.h in your code when you write the calibration procedure.
For more information on the calibration functions and VIs, refer to the NI-SCOPE Function
Reference Help or the NI-SCOPE VI Reference Help. These references can be found in the
NI High-Speed Digitizers Help. To access this help file, go to Start»Programs»National
Instruments» NI-SCOPE»Documentation»NI High-Speed Digitizers Help.
Table 1. Calibration File Locations after Installing NI-SCOPE 2.8 or Later
File Name and Location Description
IVI\Bin\niscope_32.dll NI-SCOPE driver containing the entire
NI-SCOPE API, including calibration
functions
IVI\Lib\msc\niscope.lib NI-SCOPE library for Microsoft C
containing the entire NI-SCOPE API,
including calibration functions
LabVIEW
(version)\examples\instr\
niScope
Directory of LabVIEW NI-SCOPE example
VIs, including self-calibration; access the
calibration example from the LabVIEW
function palette
LabVIEW
(version)\instr.lib\niScope
Calibrate\niScopeCal.llb
LabVIEW VI library containing VIs for
calling the NI-SCOPE calibration API;
access calibration functions from the
NI-SCOPE calibration section of the
LabVIEW function palette
IVI\Drivers\niScope\
niScopeCal.fp
CVI function panel file that includes
external calibration function prototypes and
help on using NI-SCOPE in the CVI
environment
IVI\Include\niScopeCal.h Calibration header file, which you must
include in any C program accessing
calibration functions. This file automatically
includes niScope.h, which defines the rest
of the NI-SCOPE interface
IVI\Drivers\niScope\Examples Directory of NI-SCOPE examples for CVI,
C, Visual C++, and Visual Basic

4|ni.com |NI 5922 Calibration Procedure
Documentation
Consult the following documents for information about the NI 5922 and your application
software. All documents are available on ni.com,and help files install with the software.
Self-Calibration Procedures
The NI 5922 includes precise internal circuits and references used during self-calibration to
adjust for time and temperature drift. The oscilloscope gain, offset, and flatness are all corrected
in self-calibration. Measuring the accuracy of these internal calibration circuits with another
instrument during external calibration provides traceability for the verification procedure.
Absolute accuracy is ensured by compensating for any error measured in the internal references.
Note Self-calibrate the oscilloscope before you perform verification. NI-SCOPE
includes self-calibration example programs for LabVIEW, CVI, and
Microsoft Visual C.
You can initiate self-calibration using Measurement & Automation Explorer (MAX), using the
Scope Soft Front Panel (SFP), or programmatically using NI-SCOPE.
NI PXI/PCI-5922 Getting Started Guide
Contains: NI-SCOPE installation, hardware installation, and hardware
programing instructions
NI PXI/PCI-5922 Specifications
Contains: NI 5922 specifications and calibration intervals
NI-SCOPE Readme
Contains: Operating system and application software support in NI-SCOPE
NI High Speed Digitizers Help
Contains: Detailed information about NI PXI/PCI-5922
NI-SCOPE LabVIEW Reference Help
Contains: LabVIEW programming concepts and reference information about
NI-SCOPE VIs and functions
NI-SCOPE Function Reference Help
Contains: Reference information for NI-SCOPE C functions and NI-SCOPE
C properties

NI 5922 Calibration Procedure |© National Instruments |5
MAX
To initiate self-calibration from MAX, complete the following steps:
1. Disconnect or disable any AC inputs to the oscilloscope.
2. Launch MAX.
3. Select My System»Devices and Interfaces.
4. Select the device that you want to calibrate.
5. Initiate self-calibration using one of the following methods:
•ClickSelf-Calibrate in the upper right corner of MAX.
• Right-click the name of the device in the MAX configuration tree and select
Self-Calibrate from the drop-down menu.
Scope SFP
To initiate self-calibration from the Scope SFP, complete the following steps:
1. Disconnect or disable any AC inputs to the oscilloscope.
2. Launch the Scope SFP by selecting Start»Programs»National Instruments»
NI-SCOPE»Scope Soft Front Panel.
3. Select the device you want to calibrate using the Select Device dialog box or by selecting
Edit»Change Device.
4. Launch the Calibration dialog box by selecting Utility»Self Calibration.
5. Click OK to begin self-calibration.
NI-SCOPE
To self-calibrate the NI 5922 programmatically using NI-SCOPE, complete the following steps:
1. Disconnect or disable any AC inputs to the oscilloscope.
2. Call niScope_init (niScope Initialize VI) to obtain an instrument session handle. Set the
following parameters:
•resourceName: The device name assigned by MAX
•IDQuery: NISCOPE_VAL_VI_FALSE
•resetDevice: NISCOPE_VAL_VI_FALSE
•vi: The returned session handle that you use to identify the instrument in all
subsequent instrument driver function calls

6|ni.com |NI 5922 Calibration Procedure
3. Call niScope_CalSelfCalibrate (niScope Cal Self Calibrate VI) with the following
parameters:
•sessionHandle: The instrument handle that you obtain from niScope_init
(niScope Initialize VI)
•channelList: VI_NULL
•option: VI_NULL
Because the session is a standard session rather than an external calibration session, the new
calibration constants are immediately stored in the EEPROM. Therefore, you can include
this procedure in any application that uses the oscilloscope.
4. Call niScope_close (niScope Close VI) to close the session handle. Set the following
parameter:
•vi: The instrument handle you obtained from niScope_init
External Calibration Options
External calibration involves both adjustment and verification. Adjustment is the process of
measuring and compensating for device performance to improve the measurement accuracy.
Performing an adjustment updates the calibration date, effectively resetting the calibration
interval. The device is guaranteed to meet or exceed its published specifications for the duration
of the calibration interval. Verification is the process of testing the device to ensure that the
measurement accuracy is within certain specifications. Verification can be used to ensure that
the adjustment process was successful or to determine if the adjustment process must be
performed. During verification, you must compare the measurement error to limits given in
Tables 3 through 7.
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 measurement 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
measurement errors determined during verification fall within the published specifications, but
not within the calibration test limits, the device is meeting its published specifications. However,
the device will not necessarily remain within these specifications for an additional two years.
The device will meet published specifications for the remainder of the current calibration
interval. In this case, you can perform an adjustment if you want to further improve the
measurement accuracy or reset the calibration interval. If some measurement 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 5922 Calibration Procedure |© National Instruments |7
Complete Calibration
Performing a complete calibration is the recommended way to guarantee that the NI 5922 meets
or exceeds its published specifications for a two-year calibration interval. At the end of the
complete calibration procedure, you verify that the measurement error falls within the
calibration test limits. Figure 1 shows the programming flow for complete calibration.
Figure 1. Complete Calibration Programming Flow
Optional Calibration
You can choose to skip the adjustment steps of the calibration procedure if the measurement
error is within the calibration test limits or the published specifications during the first
verification. If all of the measurement 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 5922 section for more information.
If all of the measurement 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.
Adjust (Cal Datesand
TemperaturesUpdated)
Document
Post-Adjustment
Results
Document
Pre-Adjustment
Results
Calibration/
Verification
Complete
Ye sNo
Self-Calibrate
Verify
Verify
Meets
Calibration
Te st Limits?
Review Verification/
Adjustment Procedure
or Return Device

8|ni.com |NI 5922 Calibration Procedure
Note Regardless of the results of the first verification, if you perform an
adjustment, you must verify that the measurement error falls within the calibration
test limits at the end of the calibration procedure.
Figure 2 shows the programming flow for the optional calibration.
Figure 2. Optional Calibration Programming Flow
Self-Calibrate
Verify
Ye sNo
Meets
Published
Specifications?
Ye s
Results
Within
Published Specs
(Adjustment
Optional)
No
Adjust (Cal Datesand
TemperaturesUpdated)
No
Calibration/
Verification
Complete
Ye s
Document
Post-Adjustment
Results
Document
Pre-Adjustment
Results
Review Verification/
Adjustment Procedure
or Return Device
NoYe s
Meets
Calibration
Te st Limits?
Update Calibration
Datesand Temperatures
Without Adjusting
Adjust
Anyway?
Meets
Calibration
Te st Limits?
Verify

NI 5922 Calibration Procedure |© National Instruments |9
External Calibration Requirements
Test Equipment
Table 2 lists the equipment required for externally calibrating the NI 5922. If you do not have
the recommended instruments, use these specifications to select a substitute calibration standard.
Note The delay times indicated in this procedure apply specifically to the
Fluke 9500B calibrator. If you use a different calibrator, you may need to increase
these delay times. This increase varies between calibrator models.
Test Conditions
Follow these guidelines to optimize the connections and the environment during calibration:
• Always connect the scope calibrator to the input BNC of the oscilloscope, or use a short
50 ΩBNC coaxial cable if necessary. Long cables and wires act as antennas, picking up
extra noise that can affect measurements.
• Keep relative humidity between 10 and 90%, non-condensing.
• Maintain an ambient temperature of 23 ±5 °C.
• Allow a warm-up time of at least 15 minutes after NI-SCOPE loads. Unless manually
disabled, NI-SCOPE automatically loads with the operating system and enables the device.
The warm-up time ensures that the measurement circuitry of the NI 5922 is at a stable
operating temperature.
• Ensure that the PXI chassis fan speed is set to HI, that the fan filters are clean, and that the
empty slots contain filler panels.
• Plug the PXI chassis or PC and the calibrator into the same power strip to avoid ground
loops.
Table 2. Required Equipment for NI 5922 External Calibration
Required
Equipment
Recommended
Equipment
Parameter
Measured Specification
Signal Generator Fluke 9500B
oscilloscope
calibrator
9510 Test Head
(or Wavetek 9500
with
high-stability
reference option)
Timing 2 ppm frequency
accuracy
DC Source Fluke 5700 Vert i c al G a i n DC ±50 ppm into 1 M
BNC cable — — 50 Ω

10 |ni.com |NI 5922 Calibration Procedure
External Calibration Procedures
The complete external calibration procedure consists of self-calibrating, verifying the
performance of the oscilloscope, 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.
Verifying NI 5922 Specifications
Note After the 15-minute warm-up time, always self-calibrate the NI 5922 before
beginning a verification procedure.
This section describes the program you must write to verify either the calibration test limits or
the published specifications for the NI 5922. Refer to the External Calibration Options section
to determine which limits to use in these procedures.
All verification procedures described in this section begin with niScope_init (niScope
Initialize VI) with resetDevice set to NISCOPE_VAL_TRUE and end with niScope_close
(niScope Close VI).
If any of these tests fail immediately after you perform an external adjustment, verify that you
have met the required test conditions listed in the External Calibration Requirements section
before you return the oscilloscope to NI for repair.
Vertical Offset Accuracy
Complete the following steps to verify vertical offset accuracy of the NI 5922. You must verify
both channels and each iteration listed in Table 3.
1. Disconnect all cabling from the BNC inputs of the NI 5922. No input signal is needed
because the NI 5922 internal 50 Ωresistor connects the input to ground.
2. Call niScope_ConfigureChanCharacteristics (niScope Configure Chan
Characteristics VI) with the following parameters:
•channelList: "0"
•inputImpedance: NISCOPE_VAL_50_OHM
•maxInputFrequency: 0
3. Call niScope_ConfigureVertical (niScope Configure Vertical VI) with the
following parameters:
•channelList: "0"
•range: The Range value for the current iteration from Table 3
•offset: 0.0
•coupling: NISCOPE_VAL_DC
•probeAttenuation: 1.0
•enabled: NISCOPE_VAL_TRUE

NI 5922 Calibration Procedure |© National Instruments |11
4. Call niScope_ConfigureHorizontalTiming (niScope Configure Horizontal
Timing VI) with the following parameters:
•minSampleRate: 10,000,000
•minNumPts: 100,000
•refPosition: 50.0
•numRecords: 1
•enforceRealtime: NISCOPE_VAL_TRUE
5. Call niScope_InitiateAcquisition. (niScope Initiate Acquisition VI) with the
following parameter:
•vi: The instrument handle you obtained from niScope_init
6. Call niScope_FetchMeasurement (niScope Fetch Measurement VI) with the
following parameters:
•channelList: "0"
•timeout: 1.0
•scalarMeasFunction: NISCOPE_VAL_VOLTAGE_AVERAGE
Compare the resulting average voltage to the value listed in the Calibration Test Limits
column or the Published Specifications column in Table 3 that corresponds to the vertical
range used. If the result is within the selected test limit, the device has passed this portion
of the verification.
7. Repeat steps 1 through 6 for each iteration in Table 3.
8. Repeat steps 1 through 7 for channel 1, changing the value of the channelList parameter
from "0" to "1".
Noise
Complete the following steps to verify noise performance of the NI 5922. You must verify both
channels and each iteration listed in Table 4.
1. Disconnect all cabling from the BNC inputs of the NI 5922. No input signal is needed
because the NI 5922 internal 50 Ωresistor connects the input to ground.
2. Call niScope_ConfigureChanCharacteristics (niScope Configure Chan
Characteristics VI) with the following parameters:
•channelList: "0"
•inputImpedance: NISCOPE_VAL_50_OHM
•maxInputFrequency: 0
Table 3. NI 5922 Vertical Offset Calibration
Iteration Range (V)
Calibration Test
Limits (V)
Published
Specifications (V)
1 2 ±26 µV ±50 µV
2 10 ±48 µV ±100 µV

12 |ni.com |NI 5922 Calibration Procedure
3. Call niScope_ConfigureVertical (niScope Configure Vertical VI) with the
following parameters:
•channelList:"0"
•Range: The Range value for the current iteration from Table 4
•Offset: 0.0
•Coupling: NISCOPE_VAL_DC
•ProbeAttenuation: 1.0
•Enabled: NISCOPE_VAL_TRUE
4. Call niScope_ConfigureHorizontalTiming (niScope Configure Horizontal
Timing VI) with the following parameters:
•minSampleRate: The Sample Rate value for the current iteration
•minNumPts: 65536
•refPosition: 50.0
•numRecords: 1
•enforceRealtime: NISCOPE_VAL_TRUE
5. Call niScope_InitiateAcquisition (niScope Initiate Acquisition VI) with the
following parameter:
•vi: The instrument handle you obtained from niScope_init
6. Call niScope_FetchArrayMeasurement (niScope Fetch Array Measurement VI)
with the following parameters:
•channelList: "0"
•timeout: 5.0
•arrayMeasFunction:NISCOPE_VAL_FFT_AMP_SPECTRUM_VOLTS_RMS
•measWfmSize: -1
7. Calculate the noise value from the returned voltage array V[n] using the following formula:
where iis obtained from Table 4.
a. Add up the squares of each element in the returned array starting with element i and
ending with element 26,215. The first element in the array is element 0.
b. Take the square root of the resulting sum. The result is the RMS noise between 100 Hz
and 0.4 × Sample Rate.
Compare the result from this step to the value listed in the Published Specifications
column in Table 4.
8. Repeat steps 1 through 7 for each iteration in Table 4.
Noise RMS V n
2
ni=
26215

=

NI 5922 Calibration Procedure |© National Instruments |13
9. Repeat steps 1 through 8 for channel 1, changing the value of the channelList parameter
from "0" to "1".
Input Bias Current
Complete the following steps to verify input bias current of the NI 5922. You must verify both
channels.
1. Disconnect all cabling from the BNC inputs of the NI 5922.
2. Call niScope_ConfigureChanCharacteristics (niScope Configure Chan
Characteristics VI) with the following parameters:
•channelList: "0"
•inputImpedance: NISCOPE_VAL_50_OHM
•maxInputFrequency:0
3. Call niScope_ConfigureVertical (niScope Configure Vertical VI) with the
following parameters:
•channelList: "0"
•range: 2
•offset: 0.0
•coupling: NISCOPE_VAL_DC
•probeAttenuation: 1.0
•enabled: NISCOPE_VAL_TRUE
Table 4. NI 5922 Noise Performance
Iteration Range (V)
Sample
Rate (S/s) i
Calibration
Test Limits
Published
Specifications
1 2 50 k 132 0.95 μV 1 μV
2 2 100 k 66 1.12 μV1.2 μV
3 2 1M 74.05 μV4.2 μV
4 2 5M 28.5 μV8.7 μV
5 2 10 M 1 19.1 μV20 μV
6 2 15 M 1 77 μV80 μV
7 10 50 k 132 3.23 μV3.4 μV
8 10 100 k 66 4.11 μV4.3 μV
9 10 1M 712.7 μV13 μV
10 10 5M 229.5 μV31 μV
11 10 10 M 1 88 μV92 μV
12 10 15 M 1 384 μV 401 μV

14 |ni.com |NI 5922 Calibration Procedure
4. Call niScope_ConfigureHorizontalTiming (niScope Configure Horizontal
Timing VI) with the following parameters:
•minSampleRate: 1,000,000
•minNumPts: 100,000
•refPosition: 50.0
•numRecords: 1
•enforceRealtime: NISCOPE_VAL_TRUE
5. Call niScope_InitiateAcquisition. (niScope Initiate Acquisition VI) with the
following parameter:
•vi: The instrument handle you obtained from niScope_init
6. Call niScope_FetchMeasurement (niScope Fetch Measurement VI) with the
following parameters:
•channelList: "0"
•timeout: 1.0
•scalarMeasFunction: NISCOPE_VAL_DC_ESTIMATE
7. Call niScope_ConfigureChanCharacteristics (niScope Configure Chan
Characteristics VI) with the following parameters:
•channelList: "0"
•inputImpedance: NISCOPE_VAL_1_MEG_OHM
•maxInputFrequency: 0
8. Call niScope_InitiateAcquisition (niScope Initiate Acquisition VI) with the
following parameter:
•vi: The instrument handle you obtained from niScope_init
9. Call niScope_FetchMeasurement (niScope Fetch Measurement VI) with the
following parameters:
•channelList: "0"
•timeout: 1.0
•scalarMeasFunction: NISCOPE_VAL_DC_ESTIMATE
10. Calculate the bias current using the following formula:
where a= the voltage measured in step 6
b= the voltage measured in step 9
1,000,000 is the NI 5922 impedance in ohms
Compare the resulting bias current to the value listed in the Calibration Test Limits column
or the Published Specifications column in Table 5. If the result is less than the selected test
limit, the device has passed this portion of the verification.
Bias Current ab–
1,000,000
------------------------=

NI 5922 Calibration Procedure |© National Instruments |15
11. Repeat steps 1 through 10 for channel 1, changing the value of the channelList parameter
from "0" to "1".
Vertical Gain Accuracy
Complete the following steps to verify vertical gain accuracy of the NI 5922. You must verify
both channels and each iteration listed in Table 6.
1. Call niScope_ConfigureChanCharacteristics (niScope Configure Chan
Characteristics VI) with the following parameters:
•channelList: "0"
•inputImpedance: NISCOPE_VAL_1_MEG_OHM
•maxInputFrequency: 0
2. Call niScope_ConfigureVertical (niScope Configure Vertical VI) with the
following parameters:
•channelList: "0"
•range: The Range value for the current iteration from Table 6
•offset: 0.0
•coupling: NISCOPE_VAL_DC
•probeAttenuation: 1.0
•enabled: NISCOPE_VAL_TRUE
3. Call niScope_ConfigureHorizontalTiming (niScope Configure Horizontal
Timing VI) with the following parameters:
•minSampleRate: 10,000,000
•minNumPts: 100,000
•refPosition: 50.0
•numRecords: 1
•enforceRealtime: NISCOPE_VAL_TRUE
4. Call niScope_Commit (niScope Commit VI) with the following parameter:
•vi: The instrument handle you obtained from niScope_init
5. Connect the DC voltage calibrator source to the channel 0 input of the oscilloscope and
output the positive voltage from Table 6 that corresponds to the vertical range used.
6. Wait 2,500 ms for the calibrator to settle.
7. Call niScope_InitiateAcquisition (niScope Initiate Acquisition VI) with the
following parameter:
•vi: The instrument handle you obtained from niScope_init
Table 5. NI 5922 Input Bias Current
Calibration Test Limit Published Specification
±350 nA ±500 nA

16 |ni.com |NI 5922 Calibration Procedure
8. Call niScope_FetchMeasurement (niScope Fetch Measurement VI) with the
following parameters:
•channelList: "0"
•timeout: 1.0
•scalarMeasFunction: NISCOPE_VAL_VOLTAGE_AVERAGE
9. Generate the negative voltage listed in Table 6 with the calibrator.
10. Wait 2,500 ms for the output of the calibrator to settle.
11. Call niScope_InitiateAcquisition (niScope Initiate Acquisition VI) with the
following parameter:
•vi: The instrument handle you obtained from niScope_init
12. Call niScope_FetchMeasurement (niScope Fetch Measurement VI) with the
following parameters:
•channelList: "0"
•timeout: 1.0
•scalarMeasFunction: NISCOPE_VAL_VOLTAGE_AVERAGE
13. Calculate the error in the vertical gain as a percentage of input using the following formula:
where a= the measured positive voltage
b= the measured negative voltage
c= the applied positive voltage
d= the applied negative voltage
Compare the resulting percent error to the Calibration Test Limits or the Published
Specifications listed in Table 6. If the result is within the selected test limit, the device has
passed this portion of the verification.
14. Repeat steps 1 through 13 for each iteration listed in Table 6, changing the Range, Positive
Input, and Negative Input values accordingly.
15. Move the calibrator to the oscilloscope input channel 1 and repeat steps 1 through 14,
changing the value of the channelList parameter from "0" to "1".
Table 6. NI 5922 Vertical Gain Stimuli
Iteration
Range
(V)
Positive
Input (V)
Negative
Input (V)
Calibration
Test Limits
Published
Specifications
1 2 0.9 -0.9 ±0.0293% ±0.05%
2 10 4.5 -4.5 ±0.0293% ±0.05%
error ab–
cd–
------------


1–100=

NI 5922 Calibration Procedure |© National Instruments |17
Timing Accuracy
Complete the following steps to verify the timing accuracy for the NI 5922.
Note The same time source is used for both channel 0 and channel 1, so you only
need to verify the timing accuracy on one channel.
1. Call niScope_ConfigureChanCharacteristics (niScope Configure Chan
Characteristics VI) with the following parameters:
•channelList: "0"
•inputImpedance: NISCOPE_VAL_50_OHM
•maxInputFrequency: 0
2. Call niScope_ConfigureVertical (niScope Configure Vertical VI) with the
following parameters:
•channelList: "0"
•range: 10
•offset: 0.0
•coupling: NISCOPE_VAL_DC
•probeAttenuation: 1.0
•enabled: NISCOPE_VAL_TRUE
3. Call niScope_ConfigureHorizontalTiming (niScope Configure Horizontal
Timing VI) with the following parameters:
•minSampleRate: 15,000,000
•minNumPts: 1,000,000
•refPosition: 50.0
•numRecords: 1
•enforceRealtime: NISCOPE_VAL_TRUE
4. Call niScope_Commit (niScope Commit VI) with the following parameter:
•vi: The instrument handle you obtained from niScope_init
5. Connect the scope calibrator to the channel 0 input of the oscilloscope. Configure the
calibrator to output an exact 2 MHz sine wave with 1 V peak-to-peak amplitude and 50 Ω
load impedance.
6. Wait 1,000 ms for the impedance matching and frequency of the calibrator to settle.
7. Call niScope_InitiateAcquisition (niScope Initiate Acquisition VI) with the
following parameter:
•vi: The instrument handle you obtained from niScope_init
8. Call niScope_FetchMeasurement (niScope Fetch Measurement VI) with the
following parameters:
•channelList: "0"
•timeout: 1.0
•scalarMeasFunction: NISCOPE_VAL_FFT_FREQUENCY

18 |ni.com |NI 5922 Calibration Procedure
9. Calculate the error in timing as parts per million (ppm) using the following formula:
where a= the measured frequency
Compare the result to the Calibration Test Limits or the Published Specifications listed in
Table 7. If the result is within the selected test limit, the device has passed this portion of
the verification.
Adjusting the NI 5922
If the NI 5922 successfully passed each of the verification procedures within the calibration test
limits, then an adjustment is recommended but not required to guarantee its published
specifications for the next two years. If the oscilloscope was not within the calibration test limits
for each of the verification procedures, you can perform the adjustment procedure to improve
the accuracy of the oscilloscope. Refer to the External Calibration Options section to determine
which procedures to perform.
An adjustment is required only once every two years. Following the adjustment procedure
automatically updates the calibration date and temperature in the EEPROM of the oscilloscope.
Note If the oscilloscope passed the entire verification procedure within the
calibration test limits and you do not want to perform an adjustment, you can update
the calibration date and onboard calibration temperature without making any
adjustments by completing only steps 4 and 13 in this section.
Complete all of the following steps to externally adjust the NI 5922.
1. Connect the scope calibrator to the channel 0 input of the oscilloscope. Configure the
calibrator to output an exact 1 MHz sine wave with 1 V peak-to-peak amplitude and 1 MΩ
load impedance.
2. Connect the DC source calibrator to the channel 1 input of the oscilloscope. Configure the
DC source calibrator to output an exact 4 V DC signal into a 1 MΩload impedance
(channel 1).
3. Wait 3,000 ms for the calibrator to settle.
4. Call niScope_CalStart (niScope Cal Start VI) using the user password. The factory
default password for the NI 5922 is NI.
5. Call niScope_CalSelfCalibrate (niScope Cal Self Calibrate VI) with the following
parameters:
•channelList: VI_NULL
•option: VI_NULL
Table 7. NI 5922 Timing Accuracy
Calibration Test Limit Published Specification
±5.3 ppm ±50 ppm
error a2,000,000–
2
-------------------------------------=

NI 5922 Calibration Procedure |© National Instruments |19
6. Call niScope_CalAdjustVCXO (niScope Cal Adjust VCXO VI) with the following
parameter:
•stimulusFreq: 1,000,000
Note The 1 MHz stimulus is automatically taken from channel 0.
7. Call niScope_CalAdjustRange (niScope Cal Adjust Range VI) with the following
parameters:
•channelName: "1"
•range: 0
•stimulus: 4.0
8. Configure the DC source calibrator to output an exact -4 V DC signal into a 1 MΩload
impedance (channel 1).
9. Wait 3,000 ms for the calibrator to settle.
10. Call niScope_CalAdjustRange (niScope Cal Adjust Range VI) with the following
parameters:
•channelName: "1"
•range: 0
•stimulus: -4.0
11. Disconnect or disable all inputs to the oscilloscope.
12. Call niScope_CalSelfCalibrate (niScope Cal Self Calibrate VI) with the following
parameters:
•channelList: VI_NULL
•option: VI_NULL
13. Call niScope_CalEnd with the following parameters:
•sessionHandle: The instrument handle you obtained from niScope_CalStart
•action: NISCOPE_VAL_ACTION_STORE to save the results of the calibration
You have finished adjusting the NI 5922. It is not necessary to adjust each channel individually.
However, you should repeat the entire verification procedure to verify a successful adjustment.

20 |ni.com |NI 5922 Calibration Procedure
Calibration Utilities
NI-SCOPE supports several calibration utilities that allow you to retrieve information about
adjustments performed on the NI 5922, change the external calibration password, and store
small amounts of information in the onboard EEPROM. You can retrieve some data using MAX;
however, you can retrieve all the data programmatically using NI-SCOPE functions.
MAX
To retrieve data using MAX, complete the following steps:
1. Select the device from which you want to retrieve information from My System»Devices
and Interfaces.
2. Select the Calibration tab.
You should see information about the last date and temperature for both external and
self-calibration.
NI-SCOPE
NI-SCOPE provides a full complement of calibration utility functions and VIs. Refer to the NI
High-Speed Digitizers Help for the complete function reference and VI reference for the
following utility functions:
•niScope_CalChangePassword (niScope Cal Change Password VI)
•niScope_CalFetchCount (niScope Cal Fetch Count VI)
•niScope_CalFetchDate (niScope Cal Fetch Date VI)
•niScope_CalFetchMiscInfo (niScope Cal Fetch Misc Info VI)
•niScope_CalFetchTemperature (niScope Cal Fetch Temperature VI)
•niScope_CalStoreMiscInfo (niScope Cal Store Misc Info VI)