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NI 449x Calibration Procedure

This document contains information about calibrating the National Instruments 449x devices. 
For more information about calibration, visit 

ni.com/calibration

.

Contents

Software Requirements............................................................................................................. 1
Documentation Requirements .................................................................................................. 2
Calibration Interval................................................................................................................... 2
Test Equipment......................................................................................................................... 3
Test Conditions......................................................................................................................... 4
Calibration Procedures ............................................................................................................. 5

Initial Setup....................................................................................................................... 5
Self-Calibration ................................................................................................................ 5
Verification....................................................................................................................... 5

Analog Input Performance Verification ................................................................... 6

AI Offset Verification....................................................................................... 6
AI AC Coupled Gain Accuracy Verification ................................................... 8
AI Flatness Verification.................................................................................... 10
AI DC Coupled Gain Accuracy Verification ................................................... 12

Timebase Frequency Accuracy Verification (Optional) .......................................... 14

Adjustment........................................................................................................................ 15

Analog Input Adjustment for NI 4495/4496/4498 Devices ..................................... 15
Analog Input Adjustment for NI 4492/4497/4499 Devices ..................................... 17
Updating the Calibration Date and Time without Performing Adjustment.............. 20

Where to Go for Support .......................................................................................................... 21

Software Requirements

Calibrating the NI 4492/4497/4499 requires NI-DAQmx 9.2 or later. Calibrating the 
NI 4495/4496/4498 requires NI-DAQmx 8.8 or later. You can download the NI-DAQmx driver 
from 

ni.com/downloads

. NI-DAQmx supports Self-Calibration and

 

External Calibration in 

several programming language application development environments (ADEs). When you 
install NI-DAQmx, you only need to install support for the ADE that you intend to use.

ni.com/manuals

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Summary of Contents for 449 Series

Page 1: ...on 12 Timebase Frequency Accuracy Verification Optional 14 Adjustment 15 Analog Input Adjustment for NI 4495 4496 4498 Devices 15 Analog Input Adjustment for NI 4492 4497 4499 Devices 17 Updating the Calibration Date and Time without Performing Adjustment 20 Where to Go for Support 21 Software Requirements Calibrating the NI 4492 4497 4499 requires NI DAQmx 9 2 or later Calibrating the NI 4495 449...

Page 2: ...e at ni com manuals NI DAQmx Help includes information about creating applications that use NI DAQmx The DAQ Getting Started guides NI DAQmx C Reference Help and NI DAQmx Help are installed with NI DAQmx You can also download the latest versions from the NI website at ni com manuals Calibration Interval National Instruments recommends an external calibration interval of one year for the NI 449x Ad...

Page 3: ...uracy 0 05 20 Hz to 95 kHz Function Generator Agilent 33250A Timebase frequency Frequency Range up to 10 kHz Frequency Accuracy 2 ppm Voltage Range up to 9 Vpk Voltage Source NI PXI 6233 AI DC coupled gain Voltage Range 10 V Output isolated from EARTH ground Digital Multimeter NI PXI 4070 AI DC coupled gain Voltage Measurement Accuracy 200 ppm InfiniBand to BNC Cable NI 4495 4496 4497 4498 4499 qu...

Page 4: ... circuitry is at a stable operating temperature Allow a warm up time for all of the instruments and equipment according to the manufacturer instructions BNC Cable NI 4495 4496 4497 4498 4499 quantity 17 NI PXIe 4492 quantity 9 Pomona Electronics 5697 All Characteristic Impedance 50 Ω BNC T Connector NI 4495 4496 4497 4498 4499 quantity 15 NI PXIe 4492 quantity 7 Pomona Electronics 4896 Adjustment ...

Page 5: ... The NI 449x includes precise internal circuits and references used during self calibration to adjust for any errors caused by short term fluctuations in the environment Self calibration does not require external signal connections Note Allow a 15 minute warm up period before you begin self calibration Initiate self calibration from MAX To initiate self calibration complete the following steps 1 L...

Page 6: ...f verifying an NI 4492 4497 4499 and the coupling changes from DC to AC commit the configuration using the DAQmx Control Task VI and wait 5 seconds for the input to settle 4 Start the task 5 Acquire readings with the NI 449x 6 Stop and clear the task 7 Average all of the acquired samples Table 2 NI 449x AI Offset Verification Configuration Configuration Value Minimum value 10 0 Maximum value 10 0 ...

Page 7: ...ing mode 8 Repeat steps 2 through 7 for each gain setting that your device supports Refer to Table 6 for the gain settings supported by NI 449x devices When performing step 2 adjust the gain parameter appropriately Table 3 AI Offset Limits for NI 4496 4498 As Found Test Limit As Left Test Limit Min mV Max mV Min mV Max mV 2 2 0 5 0 5 Table 4 AI Offset Limits for NI 4495 As Found Test Limit As Left...

Page 8: ...a tone with the amplitude and frequency listed in the 0 dB gain row of Table 7 Wait 5 seconds for the inputs to settle If verifying an NI 4492 4497 4499 configure the calibrator to generate a tone with the amplitude and frequency listed in the 0 dB gain row of Table 8 Wait 5 seconds for the inputs to settle Table 7 AI AC Coupled Gain Accuracy Limits for NI 4496 4498 Device Gain Calibrator Output A...

Page 9: ...upled gain accuracy of channel AI 0 at the 0 dB gain setting at the 204 8 kS s sample rate 9 If verifying an NI 4496 4498 repeat steps 2 through 8 for each gain setting that your device supports Refer to Table 10 for the gain settings supported by NI 449x devices In step 2 change the output of the calibrator based on the gain setting that is being verified Table 7 lists the amplitude and frequency...

Page 10: ...eing verified AI Flatness Verification Complete the following steps to verify the AI flatness 1 Connect the output of the calibrator to channel AI 0 on the device 2 If verifying an NI 4495 4496 4498 configure the calibrator to generate a tone with the amplitude and frequency listed in the 0 dB gain row of Table 7 Wait 5 seconds for the inputs to settle If verifying an NI 4492 4497 4499 configure t...

Page 11: ...compare it to the appropriate limits in Table 14 The value of V1 kHz is the measured amplitude of the 1 kHz tone 10 Repeat steps 2 through 9 for each gain setting that your device supports Refer to Table 12 for the gain settings supported by NI 449x devices In step 2 change the output of the calibrator based on the gain setting that is being verified Set the amplitude to the value listed in Table ...

Page 12: ...mentation of the voltage source for its connector pinout information Connect the digital multimeter voltage function in parallel with the voltage source output 2 Configure the voltage source to generate a constant voltage with the amplitude listed in the 0 dB gain row of Table 15 Measure the actual voltage source value with the digital multimeter Note The actual source value must be 95 to 105 of t...

Page 13: ... to verify the DC coupled gain accuracy of channel AI 0 at the 0 dB gain setting at the 204 8 kS s sample rate Table 15 AI DC Coupled Gain Accuracy Limits Device Gain Voltage Source Output nominal As Found Test Limit As Left Test Limit Amplitude V Min V Max V Min V Max V 0 dB 8 5 8 457 8 543 8 478 8 522 10 dB 2 686 2 672 2 700 2 679 2 693 20 dB 0 85 0 8452 0 8548 0 8476 0 8524 30 dB 0 2686 0 2668 ...

Page 14: ...opriately 9 Repeat steps 1 through 8 for all input channels on the device Connect the output of the voltage source to the channel being verified during step 1 In step 3 replace ai0 in the physical channel parameter with the channel being verified Timebase Frequency Accuracy Verification Optional Note As the timebase frequency accuracy specification is listed as typical this procedure is provided w...

Page 15: ... and temperature in the EEPROM on the NI 449x device There are two different adjustment procedures One applies to the NI 4495 4496 4498 devices The other applies to the NI 4492 4497 4499 devices Analog Input Adjustment for NI 4495 4496 4498 Devices Complete the following steps to calibrate the analog input of an NI 4495 4496 4498 device 1 Connect the output of the calibrator to all input channels ...

Page 16: ... the DAQmx Adjust DSA AI Calibration Polymorphic VI as shown below LabVIEW Block Diagram NI DAQmx Function Call Call DAQmxInitExtCal with the following parameters deviceName Dev_name password NI calHandle myCalHandle LabVIEW Block Diagram NI DAQmx Function Call In DAQmx 9 1 7 or earlier the VI will look like this In DAQmx 9 2 or later the VI will look like this as long as the Polymorphic VI select...

Page 17: ...the values found in Table 14 Analog Input Adjustment for NI 4492 4497 4499 Devices Complete the following steps to calibrate the analog input of an NI 4492 4497 4499 device 1 Connect the output of the calibrator to all input channels on the device using the BNC T connectors to split the signal in a tree formation to all the inputs 2 Initialize the AI calibration using the DAQmx Initialize External...

Page 18: ...ettings supported by NI 449x devices When performing step 3 adjust the output of the calibrator based on the amplitude and frequency in Table 19 When performing step 4 adjust the gain and reference voltage parameters appropriately 6 Connect the output of the isolated voltage source to all input channels on the device using the BNC T connectors to split the signal in a tree formation to all the inp...

Page 19: ...ng being calibrated where 0 for example represents 0 dB The coupling parameter is set to DC 9 Repeat steps 7 and 8 for each gain setting that your device supports Refer to Table 6 for the gain settings supported by NI 449x devices When performing step 7 adjust the output of the voltage source based on the amplitudes in Table 20 When performing step 8 adjust the gain and reference voltage parameter...

Page 20: ...15 and the values found in Table 14 Updating the Calibration Date and Time without Performing Adjustment You can update the calibration date and time without performing the adjustment procedure Complete the following steps to update the calibration date and time 1 Open a calibration session using the DAQmx Initialize External Calibration VI with the following parameters deviceName Dev_name passwor...

Page 21: ...access to everything from troubleshooting and application development self help resources to email and phone assistance from NI Application Engineers A Declaration of Conformity DoC is our claim of compliance with the Council of the European Communities using the manufacturer s declaration of conformity This system affords the user protection for electromagnetic compatibility EMC and product safet...

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