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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
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Related Manuals for National Instruments NI PXI-5922
Summary of Contents for National Instruments NI PXI-5922
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Page 1: Table Of Contents
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 .......................... -
Page 2: Introduction
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. - Page 3 C program accessing calibration functions. This file automatically includes , which defines the rest niScope.h of the NI-SCOPE interface Directory of NI-SCOPE examples for CVI, IVI\Drivers\niScope\Examples C, Visual C++, and Visual Basic NI 5922 Calibration Procedure | © National Instruments | 3...
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Page 4: Documentation
Documentation Consult the following documents for information about the NI 5922 and your application software. All documents are available on and help files install with the software. ni.com, 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... -
Page 5: Max
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 NI 5922 Calibration Procedure | © National Instruments | 5... -
Page 6: External Calibration Options
Call (niScope Cal Self Calibrate VI) with the following niScope_CalSelfCalibrate 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. -
Page 7: Complete Calibration
However, you cannot update the calibration date because the device will not necessarily operate within the published specifications for an additional two years. NI 5922 Calibration Procedure | © National Instruments | 7... - Page 8 Regardless of the results of the first verification, if you perform an Note 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.
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Page 9: External Calibration Requirements
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. NI 5922 Calibration Procedure | © National Instruments | 9... -
Page 10: External Calibration Procedures
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. -
Page 11: Noise
NI 5922 internal 50 Ω resistor connects the input to ground. Call (niScope Configure Chan niScope_ConfigureChanCharacteristics Characteristics VI) with the following parameters: • channelList: "0" • inputImpedance: NISCOPE_VAL_50_OHM • maxInputFrequency: NI 5922 Calibration Procedure | © National Instruments | 11... - Page 12 Call (niScope Configure Vertical VI) with the niScope_ConfigureVertical following parameters: • channelList: "0" • Range: The Range value for the current iteration from Table 4 • Offset: • Coupling: NISCOPE_VAL_DC • ProbeAttenuation: • Enabled: NISCOPE_VAL_TRUE Call (niScope Configure Horizontal niScope_ConfigureHorizontalTiming Timing VI) with the following parameters: •...
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Page 13: Input Bias Current
• inputImpedance: NISCOPE_VAL_50_OHM • maxInputFrequency: Call (niScope Configure Vertical VI) with the niScope_ConfigureVertical following parameters: • channelList: "0" • range: • offset: • coupling: NISCOPE_VAL_DC • probeAttenuation: • enabled: NISCOPE_VAL_TRUE NI 5922 Calibration Procedure | © National Instruments | 13... - Page 14 Call (niScope Configure Horizontal niScope_ConfigureHorizontalTiming Timing VI) with the following parameters: • minSampleRate: 1,000,000 • minNumPts: 100,000 • refPosition: 50.0 • numRecords: • enforceRealtime: NISCOPE_VAL_TRUE Call . (niScope Initiate Acquisition VI) with the niScope_InitiateAcquisition following parameter: • vi: The instrument handle you obtained from niScope_init Call (niScope Fetch Measurement VI) with the...
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Page 15: Vertical Gain Accuracy
Table 6 that corresponds to the vertical range used. Wait 2,500 ms for the calibrator to settle. Call (niScope Initiate Acquisition VI) with the niScope_InitiateAcquisition following parameter: • vi: The instrument handle you obtained from niScope_init NI 5922 Calibration Procedure | © National Instruments | 15... - Page 16 Call (niScope Fetch Measurement VI) with the niScope_FetchMeasurement following parameters: • channelList: "0" • timeout: • scalarMeasFunction: NISCOPE_VAL_VOLTAGE_AVERAGE 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.
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Page 17: Timing Accuracy
• vi: The instrument handle you obtained from niScope_init Call (niScope Fetch Measurement VI) with the niScope_FetchMeasurement following parameters: • channelList: "0" • timeout: • scalarMeasFunction: NISCOPE_VAL_FFT_FREQUENCY NI 5922 Calibration Procedure | © National Instruments | 17... -
Page 18: Adjusting The Ni 5922
Calculate the error in timing as parts per million (ppm) using the following formula: a 2,000,000 – error ------------------------------------- where a = the measured frequency Compare the result to the Calibration Test Limits or the Published Specifications listed in Table 7. - Page 19 NISCOPE_VAL_ACTION_STORE 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. NI 5922 Calibration Procedure | © National Instruments | 19...
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Page 20: Calibration Utilities
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. -
Page 21: Where To Go For Support
NI product. Refer to the Export Compliance Information at ni.com/legal/export-compliance for the National Instruments global trade compliance policy and how to obtain relevant HTS codes, ECCNs, and other import/export data. NI MAKES NO EXPRESS OR IMPLIED WARRANTIES AS TO THE ACCURACY OF THE INFORMATION CONTAINED HEREIN AND SHALL NOT BE LIABLE FOR ANY ERRORS.
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