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CALIBRATION PROCEDURE

NI 5922

This document describes specific programming steps for writing 
a calibration utility for the National Instruments PXI-5922 
flexible-resolution digitizer. This calibration procedure is intended 
for metrology labs.

Contents

Introduction ............................................................................................. 2

Self-Calibration................................................................................ 2
External Calibration ......................................................................... 2
Calibration Intervals ........................................................................ 2
Software and Documentation........................................................... 2

Self-Calibration Procedures .................................................................... 4

MAX ................................................................................................ 5
Scope SFP ........................................................................................ 5
NI-SCOPE ....................................................................................... 5

External Calibration Options .................................................................. 6

Complete Calibration ....................................................................... 7
Optional Calibration ........................................................................ 8

External Calibration Requirements ......................................................... 10

Test Equipment ................................................................................ 10
Test Conditions ................................................................................ 10

External Calibration Procedures ............................................................. 11

Verifying NI 5922 Specifications .................................................... 11

Vertical Offset Accuracy .......................................................... 12
Noise ......................................................................................... 13
Input Bias Current .................................................................... 15
Vertical Gain Accuracy ............................................................ 17
Timing Accuracy ...................................................................... 19
Flatness ..................................................................................... 20
Trigger Sensitivity .................................................................... 24

Adjusting the NI 5922...................................................................... 25

Summary of Contents for NI 5922

Page 1: ...on 2 Calibration Intervals 2 Software and Documentation 2 Self Calibration Procedures 4 MAX 5 Scope SFP 5 NI SCOPE 5 External Calibration Options 6 Complete Calibration 7 Optional Calibration 8 Extern...

Page 2: ...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...

Page 3: ...nding 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 consta...

Page 4: ...ing for any error measured in the internal references Note Self calibrate the digitizer before you perform verification NI SCOPE includes self calibration example programs for LabVIEW CVI and Microsof...

Page 5: ...om the Scope SFP complete the following steps 1 Disconnect or disable any AC inputs to the digitizer 2 Launch the Scope SFP by selecting Start Programs National Instruments NI SCOPE Scope Soft Front P...

Page 6: ...on 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 giv...

Page 7: ...orming 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 calibrat...

Page 8: ...ion 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 deter...

Page 9: ...mits Yes No Meets Published Specifications Yes Results Within Published Specs Adjustment Optional Update Calibration Dates and Temperatures Without Adjusting No Adjust Cal Dates and Temperatures Updat...

Page 10: ...brator to the input BNC of the digitizer or use a short 50 BNC coaxial cable if necessary Long cables and wires act as antennae picking up extra noise that can affect measurements Keep relative humidi...

Page 11: ...ion 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 traceabil...

Page 12: ...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 probeAttenua...

Page 13: ...the BNC inputs of the NI 5922 No input signal is needed because the NI 5922 internal 50 resistor connects the input to ground 2 Call niScope_ConfigureChanCharacteristics niScope Configure Chan Charac...

Page 14: ...ned 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...

Page 15: ...cal 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 4 Call niScope_ConfigureHorizonta...

Page 16: ...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_FetchMeasure...

Page 17: ...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_Con...

Page 18: ...etchMeasurement 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 per...

Page 19: ...ical 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_ConfigureHorizon...

Page 20: ...nction NISCOPE_VAL_FFT_FREQUENCY 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 o...

Page 21: ...ltime NISCOPE_VAL_TRUE 4 Call niScope_ConfigureTriggerEdge niScope Configure Trigger Edge VI with the following parameters triggerSource 0 level 0 1 slope NISCOPE_VAL_POSITIVE triggerCoupling NISCOPE_...

Page 22: ...ements within array X2 so that index 0 of the array contains the element with the largest value Denote the result as X3 A circular rotation takes the first element of the array makes it the last eleme...

Page 23: ...listed in the Calibration Test Limits column or the Published Specifications column in Table 8 If the result is less than the selected test limit the device has passed this portion of the verification...

Page 24: ...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 1...

Page 25: ...ized data from the input channel ADC when performing an analog trigger on CH 0 or CH 1 Verifying the trigger sensitivity for the input channels is not necessary Adjusting the NI 5922 If the NI 5922 su...

Page 26: ...SelfCalibrate niScope Cal Self Calibrate VI with the following parameters channelList VI_NULL option VI_NULL 6 Call niScope_CalAdjustVCXO niScope Cal Adjust VCXO VI with the following parameter stimul...

Page 27: ...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...

Page 28: ...ct supports calibration you can obtain the calibration certificate for your product at ni com calibration National Instruments corporate headquarters is located at 11500 North Mopac Expressway Austin...

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