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NI 446X Calibration Procedure

18

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8.

Acquire data using the following function.

9.

Stop the task using the following function.

10. Clear the task using the following function.

11. Average all the values in the array returned from the acquisition. This 

average is used to calculate the gain accuracy for AI 0 at –20 dB device 
gain setting. Compare this value to the limits (V) in Table 3.

NI-DAQmx Function Call

LabVIEW Block Diagram

Call 

DAQmxReadAnalogF64

 with 

the following parameters:

taskHandle

: 

myTaskHandle

numSampsPerChan

: 

-1

timeout

: 

10.0

fillMode

: 

DAQmx_Val_GroupByChannel

arraySizeInSamps

: 

102400

reserved

: 

NULL

readArray

: 

float64ArrayReturnValue

sampsPerChanRead

: 

int32PointerReturnValue

NI-DAQmx Function Call

LabVIEW Block Diagram

Call 

DAQmxStopTask

 with the following 

parameters:

taskHandle

: 

myTaskHandle

NI-DAQmx Function Call

LabVIEW Block Diagram

Call 

DAQmxClearTask

 with the following 

parameters:

taskHandle

: 

myTaskHandle

Summary of Contents for 446 Series

Page 1: ...your application NI recommends that you perform a complete calibration at least once every year Based on your measurement accuracy needs you can shorten this interval to 90 days or six months Self cal...

Page 2: ...word or value that you must supply monospace Monospace text denotes text or characters that you should enter from the keyboard sections of code programming examples and syntax examples This font is al...

Page 3: ...stants it invalidates the original calibration certificate If an external calibration is done with traceable instruments a new calibration certificate can be issued Software and Documentation Requirem...

Page 4: ...rt All Programs National Instruments NI DAQmx Base Documentation C Function Reference Manual DAQ Getting Started Guide for NI DAQ 8 1 or later This guide describes how to install your NI DAQmx for Win...

Page 5: ...different ways Refer to the standard of that language for information about how to write the character into a string You can write user defined information into or read from the EEPROM using the follo...

Page 6: ...ion stored in the EEPROM Whether the device supports self calibration Date and time of the last self calibration Temperature during the last self calibration Recommended interval for external calibrat...

Page 7: ...uInt32PointerReturnValue hour uInt32PointerReturnValue minute uInt32PointerReturnValue Call DAQmxGetSelfCalLastTemp with the following parameters deviceName dev1 data float64PointerReturnValue Call D...

Page 8: ...etExtCalLastTemp with the following parameters deviceName dev1 data float64PointerReturnValue Call DAQmxGetCalDevTemp with the following parameters deviceName dev1 data float64PointerReturnValue LabVI...

Page 9: ...e optimum relative humidity Maintain the temperature between 18 and 28 C or refer to the device specifications for the optimum temperature range Allow a warm up time of at least 15 minutes to ensure t...

Page 10: ...rocedures are explained in the following sections Note You must compare the verification limits provided in this procedure with the most recent specifications Refer to the latest NI 446X device specif...

Page 11: ...e necessary NI 446X Verification Procedure Verification determines how well the NI 446X device is meeting specifications By completing this procedure you can see how the device has drifted over time w...

Page 12: ...p 3 in LabVIEW You use the object myTaskHandle in all subsequent NI DAQmx function calls 3 Create an AI voltage channel through NI DAQmx using the following function NI DAQmx Function Call LabVIEW Blo...

Page 13: ...lowing parameters taskHandle myTaskHandle channel dev1 ai0 data 20 0 Call DAQmxSetAICoupling with the following parameters taskHandle myTaskHandle channel dev1 ai0 data DAQmx_Val_DC NI DAQmx Function...

Page 14: ...lowing parameters taskHandle myTaskHandle numSampsPerChan 1 timeout 10 0 fillMode DAQmx_Val_GroupByChannel arraySizeInSamps 102400 reserved NULL readArray float64ArrayReturnValue sampsPerChanRead int3...

Page 15: ...nnel and channel Verifying AI Gain Accuracy Complete the following steps to verify AI gain accuracy 1 Connect the output of the calibrator to the analog input channel 0 of the device 2 Output 9 0 VDC...

Page 16: ...with the following parameters taskHandle myTaskHandle physicalChannel dev1 ai0 nameToAssignToChannel terminalConfig DAQmx_Val_PseudoDiff minVal 10 0 maxVal 10 0 units DAQmx_Val_Volts CustomScaleName N...

Page 17: ...llowing function NI DAQmx Function Call LabVIEW Block Diagram Call DAQmxCfgSampClkTiming with the following parameters taskHandle myTaskHandle source NULL rate 204800 0 activeEdge DAQmx_Val_Rising sam...

Page 18: ...e limits V in Table 3 NI DAQmx Function Call LabVIEW Block Diagram Call DAQmxReadAnalogF64 with the following parameters taskHandle myTaskHandle numSampsPerChan 1 timeout 10 0 fillMode DAQmx_Val_Group...

Page 19: ...owing steps to verify AO DC offset 1 Connect the analog output channel 0 of the device to the input of the multimeter 2 Create an array of double float of size 1024 Initialize all the values in the ar...

Page 20: ...all LabVIEW Block Diagram Call DAQmxCreateAOVoltageChan with the following parameters taskHandle myTaskHandle physicalChannel dev1 ao0 nameToAssignToChannel minVal 10 0 maxVal 10 0 units DAQmx_Val_Vol...

Page 21: ...on Call DAQmxSetAOTermCfg with the following parameters taskHandle myTaskHandle channel dev1 ao0 data DAQmx_Val_PseudoDiff LabVIEW Block Diagram NI DAQmx Function Call LabVIEW Block Diagram Call DAQmx...

Page 22: ...AQmxCfgSampClkTiming with the following parameters taskHandle myTaskHandle source NULL rate 204800 0 activeEdge DAQmx_Val_Rising SampleMode DAQmx_Val_ContSamps sampsPerChanToAcquire 1024 NI DAQmx Func...

Page 23: ...Repeat steps 3 through 12 for all remaining gain values used in step 5 Refer to Table 4 for all the device gain values NI DAQmx Function Call LabVIEW Block Diagram Call DAQmxStartTask with the followi...

Page 24: ...vice AO 0 4 If you use C function calls create a task using the following function If you use LabVIEW skip this step The task is created in step 5 in LabVIEW You use the object myTaskHandle in all sub...

Page 25: ...mxSetAOIdleOutputBehavior with the following parameters taskHandle myTaskHandle channel dev1 ao0 data DAQmx_Val_HighImpedance Call DAQmxSetAOGain with the following parameters taskHandle myTaskHandle...

Page 26: ...DAQmx Function Call LabVIEW Block Diagram Call DAQmxSetWriteRegenMode with the following parameters taskHandle myTaskHandle data DAQmx_Val_AllowRegen NI DAQmx Function Call LabVIEW Block Diagram Call...

Page 27: ...l LabVIEW Block Diagram Call DAQmxWriteAnalogF64 with the following parameters taskHandle myTaskHandle numSampsPerChan 1024 autoStart FALSE timeout 10 0 dataLayout DAQmx_Val_GroupByChannel writeArray...

Page 28: ...46X devices All analog inputs use a single circuit on each device The NI 4461 analog output channels also use the same timebase frequency circuit Therefore you need to verify only the analog input fre...

Page 29: ...oltage channel through NI DAQmx using the following function NI DAQmx Function Call LabVIEW Block Diagram Call DAQmxCreateTask with the following parameter taskHandle mytaskHandleReturnValue LabVIEW d...

Page 30: ...ters taskHandle myTaskHandle channel dev1 ai0 data 0 0 Call DAQmxSetAICoupling with the following parameters taskHandle myTaskHandle channel dev1 ai0 data DAQmx_Val_DC NI DAQmx Function Call LabVIEW B...

Page 31: ...nction Call LabVIEW Block Diagram Call DAQmxReadAnalogF64 with the following parameters taskHandle myTaskHandle numSampsPerChan 1 timeout 100 0 fillMode DAQmx_Val_GroupByChannel arraySizeInSamps 25600...

Page 32: ...constants are stored in the external calibration area of the device EEPROM which ensures that you do not accidentally access or modify any calibration constants adjusted by the metrology laboratory wh...

Page 33: ...calibration or if you do not want to save the new AI calibration constants in the device EEPROM Use the action commit if you want to save the new AI calibration constants in the device EEPROM NI DAQmx...

Page 34: ...Device Output Voltage Requested High Voltage listed in Table 7 for 40 dB device gain Use this array to output a DC voltage using the device analog output channel 0 5 If you use C function calls create...

Page 35: ...m Call DAQmxCreateAOVoltageChan with the following parameters taskHandle myTaskHandle physicalChannel dev1 ao0 nameToAssignToChannel minVal 10 0 maxVal 10 0 units DAQmx_Val_Volts customScaleName NULL...

Page 36: ...etAOTermCfg with the following parameters taskHandle myTaskHandle channel dev1 ao0 data DAQmx_Val_PseudoDiff LabVIEW Block Diagram NI DAQmx Function Call LabVIEW Block Diagram Call DAQmxSetWriteRegenM...

Page 37: ...ck Diagram Call DAQmxCfgSampClkTiming with the following parameters taskHandle myTaskHandle source NULL rate 204800 0 activeEdge DAQmx_Val_Rising SampleMode DAQmx_Val_ContSamps sampsPerChanToAcquire 1...

Page 38: ...ion 15 Repeat steps 4 to 14 using the Requested Low Voltage for 40 dB device gain from Table 7 Record the multimeter DC voltage measurement as actualLowVoltage NI DAQmx Function Call LabVIEW Block Dia...

Page 39: ...vice Replace ao0 with ao1 in the function call parameters physicalChannel and channel NI DAQmx Function Call LabVIEW Block Diagram Call DAQmxAdjustDSAAOCal with the following parameters calHandle myCa...

Page 40: ...nerator to the analog input 0 of the device 2 Output a sine wave using the function generator The sine wave should have an amplitude of 9 Vp p no offset and a frequency of 1 000 000 Hz 3 Initialize th...

Page 41: ...ebase calibration or if you do not want to save the new timebase calibration constants in the device EEPROM Use the action commit if you want to save the new timebase calibration constants in the devi...

Page 42: ...oduct 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 Aust...

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