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NI 446X Calibration Procedure
Contents
This document contains information about calibrating National
Instruments PCI/PXI-4461 and PCI/PXI-4462 (NI 446X) devices.
This document does not discuss programming techniques or compiler
configuration. The National Instruments DAQmx driver includes help files
that have compiler-specific instructions and detailed function explanations.
You can install these help files when you install NI-DAQmx on the
calibration computer.
NI 446X devices should be externally calibrated at a regular interval as
defined by the measurement accuracy requirements of 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-calibration can be performed as
needed or when the temperature varies by 5 °C or more from the last
external calibration.
Conventions ............................................................................................ 2
Calibration Options ................................................................................. 3
Self-Calibration................................................................................ 3
External Calibration ......................................................................... 3
Software and Documentation Requirements........................................... 3
Software ........................................................................................... 3
Documentation................................................................................. 4
Password and User Information .............................................................. 5
Getting Calibration Information.............................................................. 6
Test Equipment ....................................................................................... 9
Test Conditions ....................................................................................... 9
Calibration Process ................................................................................. 10
Calibration Process Overview ......................................................... 10
Initial Setup...................................................................................... 10
Self-Calibration................................................................................ 11
NI 446X Verification Procedure ...................................................... 11
Verifying Analog Input Performance ....................................... 11
Verifying Analog Output Performance .................................... 19

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Summary of Contents for National Instruments 446 Series

  • Page 1: Table Of Contents

    Instruments PCI/PXI-4461 and PCI/PXI-4462 (NI 446X) devices. This document does not discuss programming techniques or compiler configuration. The National Instruments DAQmx driver includes help files that have compiler-specific instructions and detailed function explanations. You can install these help files when you install NI-DAQmx on the calibration computer.
  • Page 2: Conventions

    Verifying Timebase Frequency Accuracy.........28 NI 446X Adjustment Procedure............32 Adjusting the Analog Input ............32 Adjusting the Analog Output ............34 Adjusting the Timebase.............40 Where to Go for Support .................42 Conventions The following conventions appear in this document: » The » symbol leads you through nested menu items and dialog box options to a final action.
  • Page 3: Calibration Options

    Visual Basic 6.0, Microsoft .NET, and Borland C++. If you want to write the calibration procedure using LabVIEW, NI recommends that you use the Full or Professional Development System or the Developer Suite Professional Edition. These editions include © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 4: Documentation

    The limits you use to verify the accuracy of the devices are based on the specifications found in this document. Select Start»All Programs»National Instruments» NI-DAQ» Browse Device Documentation to launch the Device Documentation Browser. You then can select the Dynamic Signal Acquisition book to browse the list of DSA devices.
  • Page 5: Password And User Information

    You can write user-defined information into or read from the EEPROM using the following NI-DAQmx functions. NI-DAQmx Function Call Call with the following parameters: DAQmxSetCalUserDefinedInfo deviceName: dev1 data: anyUserData Call with the following parameters: DAQmxGetCalUserDefinedInfoMaxSize deviceName: dev1 data: uInt32PointerReturnValue © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 6: Getting Calibration Information

    NI-DAQmx Function Call (Continued) Call with the following parameters: DAQmxGetCalUserDefinedInfo deviceName: dev1 data: charPointerReturnValue bufferSize: anyNumberBelowMax LabVIEW Block Diagram Both password and user-defined information have a maximum of four ASCII-standard characters and are null-terminated strings. The user information is empty by default and can contain any information you find useful.
  • Page 7 Call with the following parameters: DAQmxGetExtCalRecommendedInterval deviceName: dev1 data: uInt32PointerReturnValue Call with the following parameters: DAQmxGetExtCalLastDateAndTime deviceName: dev1 year: uInt32PointerReturnValue month: uInt32PointerReturnValue day: uInt32PointerReturnValue hour: uInt32PointerReturnValue minute: uInt32PointerReturnValue © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 8 NI-DAQmx Function Call (Continued) Call with the following parameters: DAQmxGetExtCalLastTemp deviceName: dev1 data: float64PointerReturnValue Call with the following parameters: DAQmxGetCalDevTemp deviceName: dev1 data: float64PointerReturnValue LabVIEW Block Diagram NI 446X Calibration Procedure ni.com...
  • Page 9: Test Equipment

    Allow a warm-up time of at least 15 minutes to ensure that the measurement circuitry of the NI 446X is at a stable operating temperature. • Allow a warm-up time for all the instruments and equipment, according to the manufacturers’ instructions. © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 10: Calibration Process

    Calibration Process This section provides instructions for verifying and calibrating the NI 446X device. Calibration Process Overview The calibration process consists of the following steps: Initial Setup—Configure the device in NI-DAQmx. Self-Calibration—Measure the onboard reference voltage of the device and adjust the self-calibration constants. NI 446X Verification Procedure—Verify the accuracy of the device prior to calibration.
  • Page 11: Self-Calibration

    Verifying Analog Input Performance This section verifies the analog input (AI) performance of all NI 446X devices. Refer to the NI 446X Specifications for the number of channels, gain settings, and performance specifications. © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 12 Verifying AI DC Offset Complete the following steps to verify the AI DC offset: Connect a 50 Ω terminator to the analog input channel 0 of the device. The terminator grounds the input channel when it is in pseudodifferential configuration. If you use C function calls, create a task using the following function.
  • Page 13 NULL rate: 204800.0 activeEdge: DAQmx_Val_Rising sampleMode: DAQmx_Val_FiniteSamps sampsPerChanToAcquire: 102400 Start the task using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call with the following DAQmxStartTask parameters: taskHandle: myTaskHandle © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 14 Acquire data using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call with the DAQmxReadAnalogF64 following parameters: taskHandle: myTaskHandle numSampsPerChan: timeout: 10.0 fillMode: DAQmx_Val_GroupByChannel arraySizeInSamps: 102400 reserved: NULL readArray: float64ArrayReturnValue sampsPerChanRead: int32PointerReturnValue Stop the task using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call...
  • Page 15 LabVIEW. NI-DAQmx Function Call LabVIEW Block Diagram Call with the following parameter: DAQmxCreateTask LabVIEW does not require this step. taskHandle: mytaskHandleReturnValue You use the object in all subsequent NI-DAQmx myTaskHandle function calls. © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 16 Create an AI voltage channel through NI-DAQmx using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call with the DAQmxCreateAIVoltageChan following parameters: taskHandle: myTaskHandle physicalChannel: dev1/ai0 nameToAssignToChannel: "" terminalConfig: DAQmx_Val_PseudoDiff minVal: -10.0 maxVal: 10.0 units: DAQmx_Val_Volts CustomScaleName: NULL Modify the AI voltage channel property using the following functions. NI-DAQmx Function Call LabVIEW Block Diagram Call...
  • Page 17 NULL rate: 204800.0 activeEdge: DAQmx_Val_Rising sampleMode: DAQmx_Val_FiniteSamps sampsPerChanToAcquire: 102400 Start the task using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call with the following DAQmxStartTask parameters: taskHandle: myTaskHandle © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 18 Acquire data using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call with DAQmxReadAnalogF64 the following parameters: taskHandle: myTaskHandle numSampsPerChan: timeout: 10.0 fillMode: DAQmx_Val_GroupByChannel arraySizeInSamps: 102400 reserved: NULL readArray: float64ArrayReturnValue sampsPerChanRead: int32PointerReturnValue Stop the task using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call...
  • Page 19: Verifying Analog Output Performance

    If you use LabVIEW, skip this step. The task is created in step 4 in LabVIEW. NI-DAQmx Function Call LabVIEW Block Diagram Call with the following parameter: DAQmxCreateTask LabVIEW does not require this step. taskHandle: mytaskHandleReturnValue © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 20 You use the object in all subsequent NI-DAQmx myTaskHandle function calls. Create an AO Voltage channel through NI-DAQmx using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call with the DAQmxCreateAOVoltageChan following parameters: taskHandle: myTaskHandle physicalChannel: dev1/ao0 nameToAssignToChannel: "" minVal: -10.0 maxVal:...
  • Page 21 DAQmx_Val_PseudoDiff LabVIEW Block Diagram Modify the NI-DAQmx write property using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call DAQmxSetWriteRegenMode with the following parameters: taskHandle: myTaskHandle data: DAQmx_Val_AllowRegen © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 22 Configure the timing properties of the generation using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call with DAQmxCfgSampClkTiming the following parameters: taskHandle: myTaskHandle source: NULL rate: 204800.0 activeEdge: DAQmx_Val_Rising SampleMode: DAQmx_Val_ContSamps sampsPerChanToAcquire: 1024 Configure the onboard memory of the device using the following function and the array created in step 2.
  • Page 23 13. Repeat steps 3 through 12 for all remaining gain values used in step 5. Refer to Table 4 for all the device gain values. Table 4. AO Offset Limits Multimeter Reading Device Gain Min (mV) Max (mV) – 40 –1.0 –20 –1.0 –1.0 © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 24 14. Repeat steps 1 through 13 for analog output channel 1 of the device. Replace with in the function call parameters physicalChannel channel Verifying AO Gain Accuracy Complete the following steps to verify AO gain accuracy: Connect analog output channel 0 to the input of the multimeter. Create an array of double float of size 1024.
  • Page 25 DAQmx_Val_HighImpedance Call with the following parameters: DAQmxSetAOGain taskHandle: myTaskHandle channel: dev1/ao0 data: -40.0 Call with the following parameters: DAQmxSetAOTermCfg taskHandle: myTaskHandle channel: dev1/ao0 data: DAQmx_Val_PseudoDiff LabVIEW Block Diagram © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 26 Modify the NI-DAQmx write property using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call DAQmxSetWriteRegenMode with the following parameters: taskHandle: myTaskHandle data: DAQmx_Val_AllowRegen Configure the timing properties of the generation using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call DAQmxCfgSampClkTiming with the following parameters:...
  • Page 27 Output Amplitude Accuracy Amplitude Device Gain (VDC) Min (dB) Max (dB) Min (V) Max (V) – 40 0.09 – 0.04 0.04 0.089587 0.090415 –20 – 0.04 0.04 0.89587 0.90415 – 0.04 0.04 8.9587 9.0415 © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 28: Verifying Timebase Frequency Accuracy

    12. Stop the task using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call with the following DAQmxStopTask parameters: taskHandle: myTaskHandle 13. Clear the task using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call with the following DAQmxClearTask parameters: taskHandle:...
  • Page 29 Create an AI voltage channel through NI-DAQmx using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call with the DAQmxCreateAIVoltageChan following parameters: taskHandle: myTaskHandle physicalChannel: dev1/ai0 nameToAssignToChannel: "" terminalConfig: DAQmx_Val_PseudoDiff minVal: -10.0 maxVal: 10.0 units: DAQmx_Val_Volts CustomScaleName: NULL © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 30 Modify the AI voltage channel property using the following functions. NI-DAQmx Function Call LabVIEW Block Diagram Call with the DAQmxSetAIGain following parameters: taskHandle: myTaskHandle channel: dev1/ai0 data: Call with the DAQmxSetAICoupling following parameters: taskHandle: myTaskHandle channel: dev1/ai0 data: DAQmx_Val_DC Configure the timing properties of the acquisition using the following function.
  • Page 31 LabVIEW Block Diagram Call with the following DAQmxStopTask parameters: taskHandle: myTaskHandle 10. Clear the task using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call with the following DAQmxClearTask parameters: taskHandle: myTaskHandle © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 32: Ni 446X Adjustment Procedure

    11. If you use C function calls, perform an FFT on the array of data. If you use LabVIEW, use the Analog 1D Wfm 1chan Nsamp polymorphic VI to acquire data in step 8. Measure the exact frequency of the peak around 10 kHz using the Extract Single Tone Information VI with the following inputs: •...
  • Page 33 AI calibration constants in the device EEPROM. NI-DAQmx Function Call LabVIEW Block Diagram Call with the following DAQmxCloseExtCal parameters: calHandle: myCalHandle action: DAQmx_Val_Action_Commit DAQmx_Val_Action_Cancel © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 34: Adjusting The Analog Output

    Adjusting the Analog Output Complete the following steps to adjust the analog output: Connect the input of the multimeter to the analog output channel 0 of the device. Initialize the AO Calibration using the following function call. NI-DAQmx Function Call LabVIEW Block Diagram Call with the following...
  • Page 35 Modify the AO voltage channel property using the following function. NI-DAQmx Function Call Call with the following parameters: DAQmxSetAOIdleOutputBehavior taskHandle: myTaskHandle channel: dev1/ao0 data: DAQmx_Val_HighImpedance Call with the following parameters: DAQmxSetAOGain taskHandle: myTaskHandle channel: dev1/ao0 data: -40.0 © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 36 NI-DAQmx Function Call (Continued) Call with the following parameters: DAQmxSetAOTermCfg taskHandle: myTaskHandle channel: dev1/ao0 data: DAQmx_Val_PseudoDiff LabVIEW Block Diagram Modify the NI-DAQmx write property using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call DAQmxSetWriteRegenMode with the following parameters: taskHandle: myTaskHandle data:...
  • Page 37 4. NI-DAQmx Function Call LabVIEW Block Diagram Call with the DAQmxWriteAnalogF64 following parameters: taskHandle: myTaskHandle numSampsPerChan: 1024 autoStart: FALSE timeout: 10.0 dataLayout: DAQmx_Val_GroupByChannel writeArray: myDataArray reserved: NULL sampsPerChanWritten: int32PointerReturnValue © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 38 11. Start the task using the following function. NI-DAQmx Function Call LabVIEW Block Diagram Call with the following DAQmxStartTask parameters: taskHandle: myTaskHandle 12. Measure the DC voltage of the analog output channel using the multimeter in the appropriate range. Record this value as actualHighVoltage 13.
  • Page 39 9.00 (Requested High Voltage) –9.00 (Requested Low Voltage) 18. Repeat steps 1 and 4 through 17 for analog output channel 1 of the device. Replace with in the function call parameters physicalChannel channel © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 40: Adjusting The Timebase

    19. Finish the AO calibration with the following function call. Use the action if an error occurs during the AO calibration or if you do cancel not want to save the new AO calibration constants in the device EEPROM. Use the action if you want to save the new AO commit calibration constants in the device EEPROM.
  • Page 41 EEPROM. NI-DAQmx Function Call LabVIEW Block Diagram Call with the following DAQmxCloseExtCal parameters: calHandle: myCalHandle action: DAQmx_Val_Action_Commit DAQmx_Val_Action_Cancel © National Instruments Corporation NI 446X Calibration Procedure...
  • Page 42: Where To Go For Support

    Instruments trademarks. Other product and company names mentioned herein are trademarks or trade names of their respective companies. For patents covering National Instruments products, refer to the appropriate location: Help»Patents in your software, the patents.txt file on your CD, or ni.com/patents.

This manual is also suitable for:

Pci-4461Pxi-4461Pci-4462Pxi-4462

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