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NI 5421 Calibration Procedure

100 ms/s arbitrary waveform generator
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CALIBRATION PROCEDURE
NI 5421/5441
100 MS/s Arbitrary Waveform Generator
This document contains the verification and adjustment procedures for the NI 5421/5441
arbitrary waveform generator. This calibration procedure is intended for metrology labs.
Refer to
ni.com/calibration

Contents

Contents .................................................................................................................................... 1
Software.................................................................................................................................... 2
Documentation.......................................................................................................................... 3
Self-Calibration Procedures...................................................................................................... 3
MAX................................................................................................................................. 4
FGEN Soft Front Panel..................................................................................................... 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 Oscillator Frequency Accuracy.......................................................... 9
Verifying the DC Gain and Offset Accuracy ........................................................... 11
Verifying the AC Voltage Amplitude Absolute Accuracy....................................... 21
Verifying Frequency Response (Flatness)................................................................ 25
Adjusting the NI 5421/5441 ............................................................................................. 32
Adjusting the Analog Output.................................................................................... 33
Adjusting the Oscillator Frequency .......................................................................... 47
Adjusting the Calibration ADC ................................................................................ 50
Closing the External Adjustment Session ................................................................ 54
Calibration Utilities .................................................................................................................. 55
MAX................................................................................................................................. 55
FGEN SFP ........................................................................................................................ 55
NI-FGEN .......................................................................................................................... 55
Worldwide Support and Services ............................................................................................. 56
for more information about calibration solutions.

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Summary of Contents for NI 5421

  • Page 1: Table Of Contents

    CALIBRATION PROCEDURE NI 5421/5441 100 MS/s Arbitrary Waveform Generator This document contains the verification and adjustment procedures for the NI 5421/5441 arbitrary waveform generator. This calibration procedure is intended for metrology labs. Refer to for more information about calibration solutions.

  • Page 2: Software

    Software Calibrating the NI 5421 requires you to install NI-FGEN version 2.0 or later on the calibration system. Calibrating the NI 5441 requires you to install NI-FGEN version 2.3 or later on the calibration system. You can download NI-FGEN from the National Instruments website at .

  • Page 3: Documentation

    Documentation»NI Signal Generators Help. Self-Calibration Procedures The NI 5421/5441 can perform self-calibration, which adjusts the gain and offset of the main and direct analog paths. Self-calibration uses only an onboard analog-to-digital converter (ADC) to measure the output voltage. You can implement self-calibration on the NI 5421/5441 by...

  • Page 4: Max

    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 passed as the first parameter to all subsequent NI-FGEN functions.

  • Page 5: Calibration Options

    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. NI 5421/5441 Calibration Procedure | © National Instruments | 5...
  • Page 6 Table 2. Equipment Required for Calibrating the NI 5421/5441 Instrument Recommended Instrument Applicable Specification Minimum Specifications ≤ Digital multimeter (DMM) NI PXI-4070 AC accuracy, DC gain and DCV accuracy: 0.05% offset, and frequency accuracy ≥ Ω Agilent/HP 34401A DC input impedance: ≤...

  • Page 7: Test Conditions

    Test Conditions Follow these guidelines to optimize the connections and the environment during calibration: • Keep connections to the NI 5421/5441 short. Long cables and wires act as antennas, picking up extra noise that can affect measurements. • Keep relative humidity below 80%.
  • Page 8 Refer to Table 2 for information about which instrument to use for verifying each specification. Refer to Figure 1 for 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.

  • Page 9: Verifying The Oscillator Frequency Accuracy

    Verifying the Oscillator Frequency Accuracy This test verifies the frequency accuracy of the oscillator on the NI 5421/5441. Verification involves generating a 10 MHz sine wave with the NI 5421/5441 and measuring the sine wave frequency with one of the instruments from Table 2.
  • Page 10 "0" • attributeID: NIFGEN_ATTR_DIGITAL_FILTER_ENABLED • value: VI_TRUE Call to set the digital filter interpolation factor niFgen_SetAttributeViReal64 (NI-FGEN Digital Filter Interpolation Factor property) using the following parameters: • vi: The session handle returned from niFgen_init • channelName: "0" • attributeID: NIFGEN_ATTR_DIGITAL_FILTER_INTERPOLATION_FACTOR •...

  • Page 11: Verifying The Dc Gain And Offset Accuracy

    Verifying the DC Gain and Offset Accuracy This test verifies the DC gain and offset accuracy of the NI 5421/5441 into a high-impedance load by generating a number of DC voltages and offsets, measuring the voltage with a DMM, and comparing the NI 5421/5441 to the error limits.

  • Page 12: Call Nifgen_Setattributevireal64

    8. Wire 1.0 to 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 10. 12 | ni.com | NI 5421/5441 Calibration Procedure...
  • Page 13 Ideal Positive Ideal Negative Full-Scale Full-Scale As-Found As-Left Iteration Gain (Volts) (Volts) Limits (Volts) Limits(Volts) 12.000000 12.000000 -12.000000 ±0.048500 ±0.019700 10.000000 10.000000 -10.000000 ±0.040500 ±0.016500 7.000000 7.000000 -7.000000 ±0.028500 ±0.011700 NI 5421/5441 Calibration Procedure | © National Instruments | 13...
  • Page 14 - 0.006500 ±0.000526 ±0.000510 Note: Error Positive Full-Scale Value = (Measured Positive Full-Scale Value) - (Ideal Positive Full-Scale Value) Error Negative Full-Scale Value = (Measured Negative Full-Scale Value) - (Ideal Negative Full-Scale Value) 14 | ni.com | NI 5421/5441 Calibration Procedure...

  • Page 15: The Following Parameters

    • vi: The session handle returned from niFgen_init 18. Measure the DC voltage from the NI 5421/5441. 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) - (Ideal Positive Full-Scale Value) Compare this error to the calibration limits listed in Table 4.
  • Page 16 26. If any of the errors are greater than the As-Found Limits, perform an external adjustment. Verifying the Main Analog Path Offset To verify the offset of the NI 5421/5441 main analog path, complete the following steps: Create an array of waveform samples for the mid-scale DC waveform (0 VDC). This array...
  • Page 17 Note: Error Positive Offset Value = (Measured Positive Offset Value) - (Ideal Positive Offset Value)  Error Negative Offset Value = (Measured Negative Offset Value) - (Ideal Negative Offset Value) NI 5421/5441 Calibration Procedure | © National Instruments | 17...

  • Page 18: Using The Following Parameters

    • vi: The session handle returned from niFgen_init 13. Measure the negative DC voltage from the NI 5421/5441. This value is the Measured Negative Offset Value. 14. Determine the error for negative offset using the following formula: Error Negative Offset = (Measured Negative Offset Value) - (Ideal Negative Offset Value) 18 | ni.com | NI 5421/5441 Calibration Procedure...
  • Page 19 16. If any of the errors are greater than the calibration limits, perform an external adjustment. Verifying the Direct Analog Path Gain Complete the following steps to verify the NI 5421/5441 direct analog path gain. The offset is not adjustable for the direct analog path.
  • Page 20 • vi: The session handle returned from niFgen_init Measure the positive DC voltage from the NI 5421/5441. This value is the Measured Positive Full-Scale Value. Call (niFgen Abort Generation VI) to abort the waveform...

  • Page 21: Verifying The Ac Voltage Amplitude Absolute Accuracy

    • vi: The session handle returned from niFgen_init 10. Measure the negative DC voltage from the NI 5421/5441. This value is the Measured Negative Full-Scale Value. 11. Call (niFgen Abort Generation VI) to abort the waveform...
  • Page 22 22 | ni.com | NI 5421/5441 Calibration Procedure...
  • Page 23 -0.001237 0.001768 0.055000 0.038809 -0.001096 0.001485 0.037500 0.026517 -0.003359 0.006010 0.026000 0.018385 -0.0008910 0.001075 0.018500 0.013081 -0.000838 0.000969 0.013000 0.009192 -0.000799 0.000891 0.009000 0.006364 -0.000771 0.000834 0.006500 0.004596 -0.000753 0.000799 NI 5421/5441 Calibration Procedure | © National Instruments | 23...
  • Page 24 Average readings: 4 • Digits: 6.5 These values assume you are using an NI 4070 DMM. For other DMMs, use Note the range closest to the values listed in step 9. The input impedance should be equal to or greater than the values indicated in Table 2,...

  • Page 25: Verifying Frequency Response (Flatness)

    Verifying Frequency Response (Flatness) This test verifies the frequency response (flatness) of the NI 5421/5441 using a power meter. The flatness verification has two subprocedures that verify the following: • Main analog path flatness: low-gain amplifier and high-gain amplifier •...
  • Page 26 Repeat steps 11 through 20 for each iteration in Table 8, changing the Number of Samples Number of Cycles for each iteration. Table 8. NI 5421/5441 Setup for Main Analog Path Flatness Verification Published Specification Number of Number of Low-Gain...
  • Page 27 Table 8. NI 5421/5441 Setup for Main Analog Path Flatness Verification (Continued) Published Specification Number of Number of Low-Gain High-Gain Iteration Frequency Samples Cycles Amplifier Amplifier 20 MHz 1,000 -1.0 dB to -1.2 dB to +0.5 dB +0.5 dB 43 MHz 1,000 -3.0 dB to...
  • Page 28 Verifying the Direct Analog Path Flatness Complete the following steps to verify the direct analog path flatness of the NI 5421/5441, complete the following steps: Connect the NI 5421/5441 CH 0 front panel connector to the power meter using the required adapter.
  • Page 29 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 passed as the first parameter to all subsequent NI-FGEN functions.
  • Page 30 Repeat steps 11 through 20 for each iteration in Table 9, changing the Number of Samples Number of Cycles for each iteration. Table 9. NI 5421/5441 Setup for Direct Analog Path Flatness Verification Number of Iteration Frequency Number of Samples...
  • Page 31 (50 kHz) power using the following equation:     ---------- - Flatness dB   20. Compare the Flatness (dB) values calculated in step 19 to the Published Specification listed in Table 9. NI 5421/5441 Calibration Procedure | © National Instruments | 31...

  • Page 32: Adjusting The Ni 5421/5441

    If the NI 5421/5441 is not within the calibration test limits for each verification procedure, perform the adjustment procedure to improve the accuracy of the NI 5421/5441.

  • Page 33: Adjusting The Analog Output

    Along with the standard NI-FGEN attributes, the external calibration session uses a set of calibration constants that are determined during the calibration procedure and stored in the device onboard memory when the session is closed. NI-FGEN uses these calibration constants during a standard NI-FGEN session to ensure that the device operates within its specifications.
  • Page 34 In each of these subprocedures, you put the device in several configurations and take several output measurements. You then pass these measurements to NI-FGEN, which determines the calibration constants for the device. Initializing Analog Output Calibration Call (niFgen Initialize Analog...
  • Page 35 NIFGEN_ATTR_ANALOG_PATH • value: NIFGEN_VAL_FIXED_LOW_GAIN_ANALOG_PATH Call to set the postamplifier attenuation (NI-FGEN niFgen_SetAttributeViReal64 Post-Amplifier Attenuation property) using the following parameters: • vi: The session handle returned from niFgen_InitExtCal • channelName: "0" NI 5421/5441 Calibration Procedure | © National Instruments | 35...
  • Page 36 PATH_FILTER_ON_9DB VI_TRUE NIFGEN_VAL_CAL_CONFIG_MAIN_ PATH_FILTER_ON_12DB Call to set the analog filter state (NI-FGEN niFgen_SetAttributeViBoolean Analog Filter Enabled property) using the following parameters: • vi: The session handle returned from niFgen_InitExtCal • channelName: "0" 36 | ni.com | NI 5421/5441 Calibration Procedure...
  • Page 37 NIFGEN_ATTR_PRE_AMPLIFIER_ATTENUATION • value: The Preamplifier Attenuation value for the current iteration from Table 10. Complete the following steps to take the voltage measurements at the NI 5421/5441 CH 0 front panel connector into a high-impedance load: Call to set the gain DAC value (NI-FGEN Gain...
  • Page 38 • attributeID: NIFGEN_ATTR_ANALOG_PATH • value: NIFGEN_VAL_FIXED_LOW_GAIN_ANALOG_PATH Call to set the postamplifier attenuation (NI-FGEN niFgen_SetAttributeViReal64 Post-Amplifier Attenuation property) using the following parameters: • vi: The session handle returned from niFgen_InitExtCal • channelName: "0" 38 | ni.com | NI 5421/5441 Calibration Procedure...
  • Page 39 NIFGEN_VAL_CAL_CONFIG_MAIN_ PATH_FILTER_ON_12DB Call to set the analog filter state (NI-FGEN niFgen_SetAttributeViBoolean Analog Filter Enabled property) using the following parameters: • vi: The session handle returned from niFgen_InitExtCal • channelName: "0" NI 5421/5441 Calibration Procedure | © National Instruments | 39...
  • Page 40 NIFGEN_ATTR_PRE_AMPLIFIER_ATTENUATION • value: The Preamplifier Attenuation value for the current iteration from Table 11 Complete the following steps to take the voltage measurements at the NI 5421/5441 CH 0 front panel connector into a high-impedance load: Call to set the gain DAC value (NI-FGEN Gain...
  • Page 41 (NI-FGEN niFgen_SetAttributeViReal64 Pre-Amplifier Attenuation property) using the following parameters: • vi: The session handle returned from niFgen_InitExtCal • channelName: "0" • attributeID: NIFGEN_ATTR_PRE_AMPLIFIER_ATTENUATION • value: NI 5421/5441 Calibration Procedure | © National Instruments | 41...
  • Page 42 Call to set the gain DAC value (NI-FGEN Gain DAC niFgen_SetAttributeViInt32 Value property) using the following parameters: • vi: The session handle returned from niFgen_InitExtCal • channelName: "0" • attributeID: NIFGEN_ATTR_GAIN_DAC_VALUE • value: 2000 Repeat steps 5 through 8 for each of the eight iterations listed in Table 12, changing the Analog Path, Postamplifier Attenuation, and Current Configuration values for each iteration.
  • Page 43 NIFGEN_ATTR_POST_AMPLIFIER_ATTENUATION • value: The Postamplifier Attenuation value for the current iteration from Table 12 Complete the following steps to take the voltage measurements at the NI 5421/5441 CH 0 front panel connector into a high-impedance load: Call to set the offset DAC value (NI-FGEN...
  • Page 44 The session handle returned from niFgen_InitExtCal • channelName: "0" • value: Call to set the gain DAC value (NI-FGEN Gain DAC niFgen_SetAttributeViInt32 Value property) using the following parameters: • vi: The session handle returned from niFgen_InitExtCal • channelName: "0"...
  • Page 45 • vi: The session handle returned from niFgen_InitExtCal 11. Complete the following steps to take the voltage measurements at the NI 5421/5441 CH 0 front panel connector into a high-impedance load: Call (niFgen Write Binary 16...
  • Page 46 Use the DMM to measure the voltage generated by the device. This measurement is , which is used in step 12. measurement 2 Call to set the gain DAC value (NI-FGEN Gain niFgen_SetAttributeViInt32 DAC Value property) using the following parameters: 46 | ni.com | NI 5421/5441 Calibration Procedure...

  • Page 47: Adjusting The Oscillator Frequency

    Adjusting the oscillator frequency involves generating a sine wave at a desired frequency and then iteratively measuring the frequency, passing the measured value to NI-FGEN so that the oscillator can be adjusted, and then remeasuring the resulting frequency. Repeat this process until the difference between the desired and measured frequency falls within the desired tolerance, which is 4.5 ppm.
  • Page 48 "0" • attributeID: NIFGEN_ATTR_DIGITAL_FILTER_ENABLED • value: VI_TRUE Call to set the digital filter interpolation factor niFgen_SetAttributeViReal64 (NI-FGEN Digital Filter Interpolation Factor property) using the following parameters: • vi: The session handle returned from niFgen_InitExtCal • channelName: "0" • attributeID: NIFGEN_ATTR_DIGITAL_FILTER_INTERPOLATION_FACTOR •...
  • Page 49 NI 5421/5441. Call (niFgen Abort Generation VI) to abort the niFgen_AbortGeneration waveform generation using the following parameter: • vi: The session handle returned from niFgen_InitExtCal NI 5421/5441 Calibration Procedure | © National Instruments | 49...

  • Page 50: Adjusting The Calibration Adc

    Adjusting the Calibration ADC The NI 5421/5441 has an onboard calibration 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.
  • Page 51 NIFGEN_ATTR_OUTPUT_ENABLED • value: VI_TRUE 11. Call (niFgen Commit VI) to commit the attribute values to the device niFgen_Commit using the following parameter: • vi: The session handle returned from niFgen_InitExtCal NI 5421/5441 Calibration Procedure | © National Instruments | 51...
  • Page 52 • attributeID: NIFGEN_ATTR_OUTPUT_ENABLED • value: VI_TRUE 20. Call (niFgen Commit VI) to commit the attribute values to the device niFgen_Commit using the following parameter: • vi: The session handle returned from niFgen_InitExtCal 52 | ni.com | NI 5421/5441 Calibration Procedure...
  • Page 53 21. Wait 500 ms for the output to settle. 22. Use the DMM to measure the NI 5421/5441 voltage output directly into the DMM into a high-impedance load. This measurement is , which is used external measurement 0 in step 32.

  • Page 54: Closing The External Adjustment Session

    If any errors occurred during the external adjustment procedure or if you want to abort the operation, use . This function discards NIFGEN_VAL_EXT_CAL_ABORT the new calibration constants and does not change any of the calibration data stored in the onboard EEPROM. 54 | ni.com | NI 5421/5441 Calibration Procedure...

  • Page 55: Calibration Utilities

    Calibration Utilities NI-FGEN supports several calibration utilities that allow you to retrieve information about adjustments 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 using MAX or the FGEN SFP;...

  • Page 56: Worldwide Support And Services

    National Instruments Patents Notice at ni.com/patents. You can find information about end-user license agreements (EULAs) and third-party legal notices in the readme file for your NI product. Refer to the Export Compliance Information at ni.com/legal/export-compliance for the NI global trade compliance policy and how to obtain relevant HTS codes, ECCNs, and...

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