National Instruments NI 5421 Скачать руководство пользователя страница 52 | Manualshive

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National Instruments NI 5421 Скачать руководство пользователя страница 52

NI 5421/5441 Calibration Procedure

52

ni.com

The measured frequency should converge on the desired frequency.
If the measured frequency does not converge on the desired frequency
within 16 iterations, a problem may exist with your measurement
device or the NI 5421/5441.

a.

Call

niFgen_AbortGeneration

(niFgen Abort Generation VI)

to abort the waveform generation using the following parameter:

•

vi

: The session handle returned from

niFgen_InitExtCal

b.

Call

niFgen_CalAdjustOscillatorFrequency

(niFgen Cal

Adjust Oscillator Frequency VI) using the following parameters:

•

vi

: The session handle returned from

niFgen_InitExtCal

•

desiredFrequencyInHz

: The desired frequency (

10000000

)

of the generated sinusoid in Hz

•

measuredFrequencyInHz

: The

measured frequency

of

the generated sinusoid in Hz

c.

Call

niFgen_InitiateGeneration

(niFgen Initiate

Generation VI) to initiate the waveform generation using
the following parameter:

•

vi

: The session handle returned from

niFgen_InitExtCal

d.

Measure the frequency of the generated waveform. This value is
the

measured frequency

.

16. Call

niFgen_AbortGeneration

(niFgen Abort Generation VI) to

abort the waveform generation using the following parameter:

•

vi

: The session handle returned from

niFgen_InitExtCal

Adjusting the Calibration ADC

The NI 5421/5441 has an onboard calibration ADC that is used during
self-calibration. Adjusting the calibration ADC involves characterizing the
gain and offset associated with this ADC so that performing self-calibration
results in an accurately calibrated device.

1.

Call

niFgen_InitializeCalADCCalibration

(niFgen Initialize

Cal ADC Calibration VI) using the following parameter:

•

vi

: The session handle returned from

niFgen_InitExtCal

2.

Call

niFgen_WriteBinary16AnalogStaticValue

(niFgen Write

Binary 16 Analog Static Value VI) to set the main DAC value using
the following parameters:

•

vi

: The session handle returned from

niFgen_InitExtCal

•

channelName

:

"0"

•

value

:

0

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Содержание NI 5421

Страница 1: ...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...

Страница 2: ...con 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...

Страница 3: ...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...

Страница 4: ...tions 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...

Страница 5: ...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...

Страница 6: ...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 y...

Страница 7: ...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 c...

Страница 8: ...alibration 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 Fl...

Страница 9: ...etting 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 v...

Страница 10: ...Published Specifications Update Calibration Dates and Temperatures Without Adjusting Results Within Published Specs Adjustment Optional Adjust Anyway Adjust Cal Dates and Temperatures Updated Verify D...

Страница 11: ...midity 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...

Страница 12: ...rogram 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 installat...

Страница 13: ...l 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 specificati...

Страница 14: ...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...

Страница 15: ...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...

Страница 16: ...t 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...

Страница 17: ...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 fre...

Страница 18: ...t 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 verif...

Страница 19: ...GEN_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 paramete...

Страница 20: ...sentation 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...

Страница 21: ...50000 0 850000 0 001860 0 003900 11 0 600000 0 600000 0 600000 0 001460 0 002900 12 0 415000 0 415000 0 415000 0 001164 0 002160 13 0 300000 0 300000 0 300000 0 000980 0 001700 14 0 205000 0 205000 0...

Страница 22: ...returned from niFgen_init 16 Measure the DC voltage out of the NI 5421 5441 This is the Measured Positive Full Scale Value 17 Determine the error for positive full scale using the following forumla E...

Страница 23: ...m 0 VDC This array should contain 500 samples with each sample having the value 0 0 representation double 2 Call niFgen_CreateArbWaveform niFgen Create Arbitrary Waveform VI using the following parame...

Страница 24: ...425000 0 001988 0 004113 11 0 600000 0 300000 0 300000 0 001550 0 003050 12 0 415000 0 207500 0 207500 0 001226 0 002264 13 0 300000 0 150000 0 150000 0 001025 0 001775 14 0 205000 0 102500 0 102500...

Страница 25: ...itiate Generation VI to initiate the waveform generation using the following parameter vi The session handle returned from niFgen_init 7 Measure the positive DC voltage out of the NI 5421 5441 This is...

Страница 26: ...f any of the errors are greater than the Calibration Test Limit perform an external adjustment Verifying the Gain of the Direct Path To verify the gain of the NI 5421 5441 Direct path complete the fol...

Страница 27: ...using the following parameter vi The session handle returned from niFgen_init 6 Measure the positive DC voltage out of the NI 5421 5441 This is the Measured Positive Full Scale Value Table 6 Values f...

Страница 28: ...of the NI 5421 5441 This is the Measured Negative Full Scale Value 11 Call niFgen_AbortGeneration niFgen Abort Generation VI to abort the waveform generation using the following parameter vi The sessi...

Страница 29: ...ternal calibration session using the following parameters resourceName The name of the device you want to calibrate This name can be found under Devices and Interfaces in MAX password The password req...

Страница 30: ...all the standard NI FGEN functions and attributes with the external calibration session Along with the standard NI FGEN attributes the external calibration session uses a set of calibration constants...

Страница 31: ...Ext Cal Session Initialize Analog Output Calibration Adjust Main Path Pre Amp Offset Adjust Main Path Pre Amp Gain Adjust Main Path Post Amp Gain and Offset Adjust Direct Path Gain Adjust Oscillator F...

Страница 32: ...to all subsequent NI FGEN functions Adjusting the Analog Output The analog output adjustment procedure has several sub procedures that adjust the following Main path pre amplifier offset Main path pr...

Страница 33: ...Fgen_SetAttributeViInt32 to set the offset DAC value niFgen property node Calibration Offset DAC Value using the following parameters vi The session handle returned from niFgen_InitExtCal channelName...

Страница 34: ...ANCE value 50 10 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 ni...

Страница 35: ...ble 7 changing the Analog Filter Enable Pre Amplifier Attenuation and Current Configuration values for each iteration Table 7 Attributes and Values for Main Path Pre Amplifier Offset Iteration Analog...

Страница 36: ...The Pre Amplifier Attenuation value for the current iteration from Table 7 7 Take the following voltage measurements at the NI 5421 5441 CH 0 front panel connector into a high impedance load a Call n...

Страница 37: ...vi The session handle returned from niFgen_InitExtCal h Wait 500 ms for the output to settle i Use the DMM to measure the voltage output by the device This measurement is measurement 1 which is used...

Страница 38: ...measuredOutputs An array containing three elements the three output voltages measurement 0 measurement 1 measurement 2 that you measured in the order that you measured them Adjusting the Main Path Pre...

Страница 39: ...eturned from niFgen_InitExtCal channelName 0 attributeID NIFGEN_ATTR_ANALOG_FILTER_ENABLED value The Analog Filter Enable value for the current iteration from Table 8 Table 8 Attributes and Values for...

Страница 40: ...rom niFgen_InitExtCal channelName 0 attributeID NIFGEN_ATTR_GAIN_DAC_VALUE value 1500 b Call niFgen_WriteBinary16AnalogStaticValue niFgen Write Binary 16 Analog Static Value VI to set the main DAC val...

Страница 41: ...d in step 7 7 Call niFgen_CalAdjustMainPathPreAmpGain niFgen Cal Adjust Main Path Pre Amp Gain VI using the following parameters vi The session handle returned from niFgen_InitExtCal channelName 0 con...

Страница 42: ...N_ATTR_ANALOG_FILTER_ENABLED value VI_FALSE 3 Call niFgen_SetAttributeViReal64 to set the pre amplifier attenuation niFgen property node Calibration Pre Amplifier Attenuation using the following param...

Страница 43: ...for the current iteration from Table 9 Table 9 Attributes and Values for the Main Path Post Amplifier Gain and Offset Iteration Analog Path Post Amp Attenuation Current Configuration 1 NIFGEN_VAL_FIXE...

Страница 44: ...ed from niFgen_InitExtCal c Wait 500 ms for the output to settle d Use the DMM to measure the voltage output by the device This measurement is measurement 0 which is used in step 8 e Call niFgen_SetAt...

Страница 45: ...ray containing two elements the two output voltages measurement 0 measurement 1 that you measured in order Adjusting the Direct Path Gain 1 Call niFgen_WriteBinary16AnalogStaticValue niFgen Write Bina...

Страница 46: ...Call niFgen_SetAttributeViReal64 to set the post amplifier attenuation niFgen property node Calibration Post Amplifier Attenuation using the following parameters vi The session handle returned from ni...

Страница 47: ...value using the following parameters vi The session handle returned from niFgen_InitExtCal channelName 0 value 32767 b Call niFgen_SetAttributeViInt32 to set the gain DAC value niFgen property node Ca...

Страница 48: ...InitExtCal channelName 0 attributeID NIFGEN_ATTR_GAIN_DAC_VALUE value 1500 l Call niFgen_Commit niFgen Commit VI to commit the attribute values to the device using the following parameter vi The sessi...

Страница 49: ...or can be adjusted and then re measuring the resulting frequency This process is repeated until the difference between the desired and measured frequency falls within the desired tolerance 4 5 ppm Thi...

Страница 50: ...ll 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_...

Страница 51: ...mples 500 of the waveform 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...

Страница 52: ...waveform generation using the following parameter vi The session handle returned from niFgen_InitExtCal d Measure the frequency of the generated waveform This value is the measured frequency 16 Call...

Страница 53: ...Fgen_SetAttributeViInt32 to set the offset DAC value niFgen property node Calibration Offset DAC Value using the following parameters vi The session handle returned from niFgen_InitExtCal channelName...

Страница 54: ...on Output Enabled using the following parameters vi The session handle returned from niFgen_InitExtCal channelName 0 attributeID NIFGEN_ATTR_OUTPUT_ENABLED value VI_TRUE 11 Call niFgen_Commit niFgen C...

Страница 55: ...d from niFgen_InitExtCal numberOfReadsToAverage 3 returnCalibratedValue VI_FALSE calADCValue A ViReal64 variable The variable passed by reference through this parameter receives the voltage measured b...

Страница 56: ...r the output to settle 27 Call niFgen_ReadCalADC niFgen Read CAL ADC VI to measure the analog output voltage with the onboard calibration ADC using the following parameters vi The session handle retur...

Страница 57: ...calibration ADC in the order that you measured them 33 Call niFgen_SetAttributeViBoolean to disable the analog output niFgen property node Basic Operation Output Enabled using the following parameter...

Страница 58: ...ments performed on the NI 5421 5441 restore an external calibration change the external calibration password and store small amounts of information in the onboard EEPROM You can retrieve some data usi...

Страница 59: ...the complete function reference The utility functions include niFgen_RestoreLastExtCalConstants niFgen_GetSelfCalSupported niFgen_GetSelfCalLastDateAndTime niFgen_GetExtCalLastDateAndTime niFgen_GetS...

Страница 60: ...round the world to help address your support needs For telephone support in the United States create your service request at ni com support and follow the calling instructions or dial 512 795 8248 For...

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