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NI 5421, Процедура калибровки

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NI 5421/5441 Calibration Procedure 

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  © National Instruments 

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  5

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 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 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.

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.

Содержание 5421

Страница 1: ...4 NI FGEN 4 Calibration Options 5 Calibration Requirements 5 Test Equipment 5 Test Conditions 7 System Setup 7 Calibration Procedures 7 Verifying NI 5421 5441 Specifications 7 Verifying the Oscillato...

Страница 2: ...iFgen h file To use these constants in C you must include niFgen h in your code when you write the calibration procedure Refer to the following table for file locations The calibration process is desc...

Страница 3: ...d 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...

Страница 4: ...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...

Страница 5: ...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 calibr...

Страница 6: ...nce 1 G ACV accuracy 0 16 AC input impedance 1 M Bandwidth 100 kHz Male banana to female BNC adapter Male BNC to female SMB cable 50 RG 223 Frequency counter Agilent HP 53131A or HP 53132A with timeba...

Страница 7: ...the NI 5421 5441 adjusting the calibration constants and re verifying performance after the adjustments In some cases the complete calibration procedure may not be required Refer to the Calibration O...

Страница 8: ...r the names and locations of the NI PXI 5421 5441 and the NI PCI 5421 front panel connectors The NI PXI 5421 5441 is pictured on the left The NI PCI 5421 is pictured on the right Figure 1 NI PXI 5421...

Страница 9: ...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 pa...

Страница 10: ...a total of 500 samples and 50 sine wave cycles Because you set the sample rate to 100 MS s and use 10 samples per cycle the resulting waveform is a 10 MHz sine wave Note The sample values of this wave...

Страница 11: ...r 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 subprocedures that ver...

Страница 12: ...ANALOG_PATH 6 Call niFgen_SetAttributeViReal64 to set the output impedance NI FGEN Output Impedance property using the following parameters vi The session handle returned from niFgen_init channelName...

Страница 13: ...niFgen Create Waveform DBL VI in step 13 13 Call niFgen_CreateWaveformF64 niFgen Create Waveform DBL VI using the following parameters vi The session handle returned from niFgen_init wfmSize The size...

Страница 14: ...05000 0 105000 0 105000 0 000920 0 000668 17 0 075000 0 075000 0 075000 0 000800 0 000620 18 0 055000 0 055000 0 055000 0 000720 0 000588 19 0 037500 0 037500 0 037500 0 000650 0 000560 20 0 026000 0...

Страница 15: ...421 5441 This value is the Measured Positive Full Scale Value 19 Determine the error for positive full scale using the following formula Error Positive Full Scale Measured Positive Full Scale Value Id...

Страница 16: ...the element input and specify a dimension size of 500 Wire the initialized array output of the Initialize Array function to the Waveform Data Array input of the niFgen Create Waveform DBL VI in step...

Страница 17: ...00 0 425000 0 004113 0 001988 11 0 600000 0 300000 0 300000 0 003050 0 001550 12 0 415000 0 207500 0 207500 0 002264 0 001226 13 0 300000 0 150000 0 150000 0 001775 0 001025 14 0 205000 0 102500 0 102...

Страница 18: ...e error for positive offset using the following formula Error Positive Offset Measured Positive Offset Value Ideal Positive Offset Value Compare this error to the calibration limits listed in Table 5...

Страница 19: ...nit channelName 0 attributeID NIFGEN_ATTR_ARB_OFFSET value 0 2 Call niFgen_SetAttributeViInt32 to set the analog path NI FGEN Analog Path property using the following parameters vi The session handle...

Страница 20: ...5441 This value is the Measured Positive Full Scale Value 7 Call niFgen_AbortGeneration niFgen Abort Generation VI to abort the waveform generation using the following parameter vi The session handle...

Страница 21: ...ter than the calibration limits listed in Table 6 perform an external adjustment 16 Call niFgen_close niFgen Close VI to close the instrument driver session to destroy the instrument driver session an...

Страница 22: ...T_ARB Arbitrary Waveform 7 Create an array of waveform samples The waveform array should contain a single cycle sine wave of 2 000 samples and an amplitude of 1 8 LabVIEW Only You must call the niFgen...

Страница 23: ...5 1 166726 0 012374 0 024042 9 1 250000 5 0 883883 0 009546 0 018385 10 0 850000 5 0 601041 0 006718 0 012728 11 0 600000 0 5 0 424264 0 004950 0 009192 12 0 415000 0 5 0 293449 0 003642 0 006576 13 0...

Страница 24: ...iteration 13 Call niFgen_InitiateGeneration niFgen Initiate Generation VI using the following parameter vi The session handle returned from niFgen_init 14 Wait 5 seconds for the output of the NI 5421...

Страница 25: ...ssion 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 p...

Страница 26: ...10 Call niFgen_ConfigureSampleRate niFgen Set Sample Rate VI using the following parameters vi The session handle returned from niFgen_init Sample Rate 100 MS s 100000000 Repeat steps 11 through 20 f...

Страница 27: ...ter to a waveform The variable passed by reference through this parameter acts as a handle to the waveform and can be used for setting the active waveform changing the data in the waveform building se...

Страница 28: ...eviation from the reference 50 kHz power using the following equation 20 Compare the Flatness dB calculated in step 19 to the Published Specification value for the current amplifier path listed in Tab...

Страница 29: ...Call niFgen_SetAttributeViReal64 to set the offset NI FGEN Offset property using the following parameters vi The session handle returned from niFgen_init channelName 0 attributeID NIFGEN_ATTR_ARB_OFF...

Страница 30: ...Data Array input of the niFgen Create Waveform DBL VI in step 13 13 Call niFgen_CreateWaveformF64 niFgen Create Waveform DBL VI using the following parameters vi The session handle returned from niFg...

Страница 31: ...all niFgen_SetAttributeViReal64 to set the digital filter interpolation factor NI FGEN Digital Filter Interpolation Factor property using the following parameters vi The session handle returned from n...

Страница 32: ...e you want to calibrate This name can be found under Devices and Interfaces in MAX password The password required to open an external calibration session If this password has not been changed since ma...

Страница 33: ...xt Cal VI as shown in the following figure Figure 2 NI 5421 5441 External Calibration Procedure Adjusting the Analog Output The analog output adjustment procedure has several subprocedures that adjust...

Страница 34: ...NI FGEN Analog Path property using the following parameters vi The session handle returned from niFgen_InitExtCal channelName 0 attributeID NIFGEN_ATTR_ANALOG_PATH value NIFGEN_VAL_FIXED_LOW_GAIN_ANA...

Страница 35: ...tributeID NIFGEN_ATTR_OUTPUT_IMPEDANCE value 50 10 Call niFgen_SetAttributeViBoolean to enable the analog output NI FGEN Output Enabled property using the following parameters vi The session handle re...

Страница 36: ...ollowing parameters vi The session handle returned from niFgen_InitExtCal channelName 0 Table 10 Attributes and Values for Main Analog Path Preamplifier Offset Iteration Analog Filter Enable Preamplif...

Страница 37: ...teID NIFGEN_ATTR_GAIN_DAC_VALUE value 2000 b Call niFgen_SetAttributeViInt32 to set the offset DAC value NI FGEN Offset DAC Value property using the following parameters vi The session handle returned...

Страница 38: ..._InitExtCal channelName 0 configuration The Current Configuration value for the current iteration from Table 10 gainDACValues An array containing two elements the two values 2000 1000 that you set as...

Страница 39: ...ty using the following parameters vi The session handle returned from niFgen_InitExtCal channelName 0 Table 11 Attributes and Values for Main Analog Path Preamplifier Gain Iteration Analog Filter Enab...

Страница 40: ...GEN_ATTR_GAIN_DAC_VALUE value 1500 b Call niFgen_WriteBinary16AnalogStaticValue niFgen Write Binary 16 Analog Static Value VI to set the main DAC value using the following parameters vi The session ha...

Страница 41: ...order that you measured them offsetDACValues An array containing one element the value 32000 that you set for the offset DAC measuredOutputs An array containing two elements the two output voltages m...

Страница 42: ...and Values for the Main Analog Path Postamplifier Gain and Offset Iteration Analog Path Post amplifier Attenuation Current Configuration 1 NIFGEN_VAL_FIXED_ LOW_GAIN_ANALOG_PATH 0 NIFGEN_VAL_CAL_ CONF...

Страница 43: ...ll niFgen_Commit niFgen Commit VI to commit the attribute values to the device using the following parameter vi The session handle returned from niFgen_InitExtCal c Wait 500 ms for the output to settl...

Страница 44: ...ll niFgen_SetAttributeViInt32 to set the gain DAC value NI FGEN Gain DAC Value property using the following parameters vi The session handle returned from niFgen_InitExtCal channelName 0 attributeID N...

Страница 45: ...BLED value VI_TRUE 9 Call niFgen_SetAttributeViInt32 to set the analog path value NI FGEN Analog Path property using the following parameters vi The session handle returned from niFgen_InitExtCal chan...

Страница 46: ...tput to settle i Use the DMM to measure the voltage generated by the device This measurement is measurement 1 which is used in step 12 j Call niFgen_WriteBinary16AnalogStaticValue niFgen Write Binary...

Страница 47: ...C in order measuredOutputs An array containing four elements the four output voltages measurement 0 measurement 1 measurement 2 measurement 3 that you measured in order Adjusting the Oscillator Freque...

Страница 48: ...using the following parameters vi The session handle returned from niFgen_InitExtCal channelName 0 attributeID NIFGEN_ATTR_ANALOG_FILTER_ENABLED value VI_TRUE 6 Call niFgen_SetAttributeViBoolean to se...

Страница 49: ...meter receives the value waveform handle that identifies the waveform created by this function 12 Call niFgen_SetAttributeViInt32 to choose the sine waveform NI FGEN Arbitrary Waveform Handle property...

Страница 50: ...ADC used during self calibration To adjust the calibration ADC characterize the gain and offset associated with this ADC so that a self calibration results in an accurately calibrated device 1 Call n...

Страница 51: ...ibuteID NIFGEN_ATTR_PRE_AMPLIFIER_ATTENUATION value 0 8 Call niFgen_SetAttributeViReal64 to set the postamplifier attenuation NI FGEN Post Amplifier Attenuation property using the following parameters...

Страница 52: ...t niFgen Commit VI to commit the attribute values to the device using the following parameter vi The session handle returned from niFgen_InitExtCal 17 Wait 500 ms for the output to settle 18 Call niFg...

Страница 53: ...0 ms for 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 handl...

Страница 54: ...rs vi The session handle returned from niFgen_InitExtCal channelName empty string attributeID NIFGEN_ATTR_CAL_ADC_INPUT value NIFGEN_VAL_GROUND 35 Call niFgen_Commit niFgen Commit VI to commit the att...

Страница 55: ...erature for both external and self calibration FGEN SFP To retrieve data using the FGEN SFP complete the following steps 1 Launch the FGEN SFP 2 Select the device from which you want to retrieve infor...

Страница 56: ...resource for technical support At ni com support you have access to everything from troubleshooting and application development self help resources to email and phone assistance from NI Application E...

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