National Instruments NI 9229 Manual

CALIBRATION PROCEDURE
NI 9229/9239
4-Channel, ±60 V/±10 V, 24-Bit Simultaneous, Channel-to-Channel
Isolated Analog Input Modules
This document contains the verification and adjustment procedures for the National
Instruments 9229/9239. For more information about calibration solutions, visit ni.com/
calibration.
Contents
Software.................................................................................................................................... 1
Documentation.......................................................................................................................... 2
Test Equipment......................................................................................................................... 3
Test Conditions......................................................................................................................... 3
Initial Setup............................................................................................................................... 3
Verification ............................................................................................................................... 4
Accuracy Verification....................................................................................................... 4
Gain Matching Verification.............................................................................................. 6
Phase Matching Verification ............................................................................................ 7
Adjustment................................................................................................................................ 9
Accuracy Adjustment ....................................................................................................... 9
EEPROM Update ..................................................................................................................... 10
Reverification ........................................................................................................................... 10
Accuracy Under Calibration Conditions .................................................................................. 10
Worldwide Support and Services ............................................................................................. 11
Software
Calibrating the NI 9229/9239 requires the installation of NI-DAQmx 9.5 or later on the
calibration system. You can download NI-DAQmx from ni.com/downloads. NI-DAQmx
supports LabVIEW, LabWindows™/CVI™, ANSI C, Microsoft Visual C++, Microsoft Visual
Basic .NET, and Microsoft Visual C#. When you install NI-DAQmx you only need to install
support for the application software that you intend to use.

2|ni.com |NI 9229/9239 Calibration Procedure
Documentation
Consult the following documents for information about the NI 9229/9239, NI-DAQmx, and
your application software. All documents are available on ni.com and help files install with the
software.
NI cDAQ-9174/9178 USB Chassis Quick Start
NI-DAQmx installation and hardware setup
NI 9229/9239 Operating Instructions and Specifications
NI 9229/9239 specific information, specifications, and calibration interval
NI-DAQmx Readme
Operating system and application software support in NI-DAQmx
LabVIEW Help
LabVIEW programming concepts and reference information about NI-DAQmx
VIs and functions
NI-DAQmx C Reference Help
Reference information for NI-DAQmx C functions and NI-DAQmx C properties
NI-DAQmx .NET Help Support for Visual Studio
Reference information for NI-DAQmx .NET methods and NI-DAQmx .NET
properties, key concepts, and a C enum to .NET enum mapping table

NI 9229/9239 Calibration Procedure |© National Instruments |3
Test Equipment
Table 1 lists the equipment recommended for the performance verification and adjustment
procedures. If the recommended equipment is not available, select a substitute using the
requirements listed in Table 1.
Test Conditions
The following setup and environmental conditions are required to ensure the NI 9229/9239
meets published specifications.
• Keep connections to the device as short as possible. Long cables and wires act as antennas,
picking up extra noise that can affect measurements.
• Verify that all connections to the NI 9229/9239 are secure.
•(NI 9229/9239 with screw-terminal) Use shielded copper wire for all cable connections
to the device.
• Use twisted-pairs wire to eliminate noise and thermal offsets.
• Maintain an ambient temperature of 23 °C ± 5 °C.
• Keep relative humidity below 80%.
• Allow a warm-up time of at least 10 minutes to ensure that the NI 9229/9239 measurement
circuitry is at a stable operating temperature.
Initial Setup
Complete the following steps to set up the NI 9229/9239.
1. Install the NI-DAQmx driver software.
2. Make sure the NI cDAQ-9178 power source is not connected.
Table 1. Recommended Equipment
Equipment
Recommended
Model
Parameter
Measured Requirements
Calibrator Fluke 5700A Accuracy,
Adjustment
Use a high-precision voltage source
with an accuracy ≤100 ppm and an
output impedance ≤50 Ω.
Function
Generator
NI 4461 Gain Matching,
Phase Matching
Use a function generator capable of
sourcing both 1 kHz and 20 kHz
±10 Vpk AC sinusoidal signals with
amplitude uncertainty of ±10%.
Chassis NI cDAQ-9178 All —

4|ni.com |NI 9229/9239 Calibration Procedure
3. Connect the NI cDAQ-9178 to the system safety ground.
a. Attach a ring lug to a 14 AWG (1.6 mm) wire.
b. Connect the ring lug to the ground terminal on the side of the NI cDAQ-9178 using
the ground screw.
c. Attach the other end of the wire to the system safety ground.
4. Install the NI 9229/9239 in slot 8 of the NI cDAQ-9178 chassis. Leave slots 1 through 7 of
the NI cDAQ-9178 chassis empty.
5. Connect the NI cDAQ-9178 chassis to your host computer.
6. Connect the power source to the NI cDAQ-9178 chassis.
7. Launch Measurements & Automation Explorer (MAX).
8. Right-click the device name and select Self-Test to ensure that the device is working
properly.
Verification
The following performance verification procedures describe the sequence of operation and
provide test points required to verify the NI 9229/9239. The verification procedures assume that
adequate traceable uncertainties are available for the calibration references.
Accuracy Verification
Complete the following procedure to determine the As-Found status of the NI 9229/9239.
1. Set the calibrator to Standby mode (STBY).
2. Connect the NI 9229/9239 to the calibrator as shown in Figure 1.
Figure 1. Accuracy Verification Connections
3. Set the calibrator voltage to a Test Point value indicated in Tables 4 or 5.
4. Set the calibrator to Operate mode (OPR).
NI 9229/9239 with
Screw-Terminal
Calibrator
HI
LO
AI1
–
+
AI0
–
+
AI2
–
+
AI3
–
+
NI 9229/9239
with BNC
Calibrator
HI
LO
AI1
AI0
AI2
AI3
+
–
+
–
+
–
+
–

NI 9229/9239 Calibration Procedure |© National Instruments |5
5. Acquire and average samples.
a. Create and configure an AI voltage task on the NI 9229/9239 according to Table 2.
b. Configure the AI voltage task timing according to Table 3.
c. Start the task.
d. Read samples from the NI 9229/9239.
e. Average the samples per channel.
f. Clear the task.
6. Compare the per channel average to the limits in Table 4 or Table 5.
Note The test limits listed in Table 4 and 5 are derived using the values in Table 14.
Table 2. NI 9229/9239 Configuration for Accuracy Verification
Module
Physical
Channels Min (V) Max (V)
Scaled
Units
Terminal
Configuration
9229 AI0:3 -60 60 Vo l t s Differential
9239 AI0:3 -10 10 Vo l t s Differential
Table 3. NI 9229/9239 Timing Configuration
Sample Mode Samples Per Channel Rate
Finite Samples 2000 8330
Table 4. NI 9229 Verification Test Limits for Accuracy
Range Test Point 1-Year Limits
Min (V) Max (V) Location Value (V) Lower Limit (V) Upper Limit (V)
-60 60 Max 57.00000 56.9695 57.0304
Mid 0.00 -0.00766 0.00766
Min -57.00000 -57.0304 -56.9695
Table 5. NI 9239 Verification Test Limits for Accuracy
Range Test Point 1-Year Limits
Min (V) Max (V) Location Value (V) Lower Limit (V) Upper Limit (V)
-10 10 Max 9.50000 9.4948 9.50515
Mid 0.00 -0.00135 0.00135
Min -9.50000 -9.50515 -9.4948

6|ni.com |NI 9229/9239 Calibration Procedure
7. Set the calibrator to Standby mode (STBY).
8. Repeat steps 3 through 7 for each test point in Table 4.
9. Disconnect the calibrator from the device.
Gain Matching Verification
Complete the following procedure to determine the As-Found status of the NI 9229/9239.
1. Connect the NI 9229/9239 to the function generator as shown in Figure 2.
Figure 2. Gain Matching Verification Connections
2. Configure function generator according to Table 6.
3. Acquire and average samples.
a. Create and configure an AI voltage task on the NI 9229/9239 according to Table 7.
Table 6. Function Generator Configuration for Gain Matching Verification
Signal Type Amplitude (Vpk)Frequency (kHz)
Sinewave 9 20
Table 7. NI 9229/9239 Configuration for Gain Matching Verification
Module
Physical
Channels Min (V) Max (V)
Scaled
Units
Terminal
Configuration
9229 AI0:3 -60 60 Vo l t s Differential
9239 AI0:3 -10 10 Vo l t s Differential
NI 9229/9239 with
Screw-Terminal
Function
Generator
HI
LO
AI1
–
+
AI0
–
+
AI2
–
+
AI3
–
+
NI 9229/9239
with BNC
Function
Generator
HI
LO
AI1
AI0
AI2
AI3
+
–
+
–
+
–
+
–

NI 9229/9239 Calibration Procedure |© National Instruments |7
b. Configure the AI voltage task timing according to Table 3.
c. Enable the function generator.
d. Start the task and wait for it to complete.
e. Calculate the amplitude for each reading and record the result as AmplitudeAcq.
f. Disable the function generator.
g. Clear the task.
4. Perform the following calculation using the AmplitudeAcq value.
5. Repeat step 4 for each channel.
6. Compare the channel-to-channel gain difference to the maximum limit of ±0.22 dB.
If the Gain Matching verification procedure determines that the NI 9229/9239 is outside of the
limits, refer to Worldwide Support and Services for assistance in returning the device to NI.
Phase Matching Verification
Complete the following procedure to determine the As-Found status of the NI 9229/9239.
1. Connect the NI 9229/9239 to the function generator as shown in Figure 3.
Figure 3. Phase Matching Verification Connections
Table 8. NI 9229/9239 Timing Configuration
Sample Mode Samples Per Channel Rate
Finite Samples 25000 50000
Amplitude dB() 20 10 log×AmplitudeAcq
9V
----------------------------------- 





=
NI 9229/9239 with
Screw-Terminal
Function
Generator
HI
LO
AI1
–
+
AI0
–
+
AI2
–
+
AI3
–
+
NI 9229/9239
with BNC
Function
Generator
HI
LO
AI1
AI0
AI2
AI3
+
–
+
–
+
–
+
–

8|ni.com |NI 9229/9239 Calibration Procedure
2. Configure function generator according to Table 9.
3. Set the function generator frequency to a value indicated in Table 12.
4. Acquire and average samples.
a. Create and configure an AI voltage task on the NI 9229/9239 according to Table 10.
b. Configure the AI voltage task timing according to Table 3.
c. Enable the function generator.
d. Start the task.
e. Read samples.
f. Disable the function generator.
g. Clear the task.
5. Calculate the phase for each channel on the NI 9229/9239. NI recommends using the
Extract Single Tone Information VI to calculate phase.
Table 9. Function Generator Configuration for Phase Matching Verification
Signal Type Amplitude (Vpk)
Sinewave 9
Table 10. NI 9229/9239 Configuration for Phase Matching Verification
Module
Physical
Channels Min (V) Max (V)
Scaled
Units
Terminal
Configuration
9229 AI0:3 -60 60 Vo l t s Differential
9239 AI0:3 -10 10 Vo l t s Differential
Table 11. NI 9229/9239 Timing Configuration
Sample Mode Samples Per Channel Rate
Finite Samples 25000 50000

NI 9229/9239 Calibration Procedure |© National Instruments |9
6. Compare the channel-to-channel phase difference to the limits in Table 12.
7. Repeat steps 2 through 6 for each test point in Table 12.
If the Phase Matching verification procedure determines that the NI 9229/9239 is outside of the
limits, refer to Worldwide Support and Services for assistance in returning the device to NI.
Adjustment
The following performance adjustment procedure describes the sequence of operation required
to adjust the NI 9229/9239.
Accuracy Adjustment
Complete the following procedure to adjust the accuracy performance of the NI 9229/9239.
1. Set the calibrator to Standby mode (STBY).
2. Connect the NI 9229/9239 to the calibrator as shown in Figure 1.
Note If the calibrator outputs are truly floating, the negative output must be
connected to a quiet earth ground as well as AI- to give the entire system a ground
reference.
3. Adjust the NI 9229/9239.
a. Initialize a calibration session on the NI 9229/9239. The default password is NI.
b. Input the external temperature in degrees Celsius.
c. Call the NI 9229/9239 get C Series adjustment points function to obtain an array of
recommended calibration voltages for the NI 9229/9239.
d. Set the calibrator to a reference value determined by the array of recommended
calibration voltages.
e. Set the calibrator to Operate mode (OPR).
f. Call and configure the NI 9229/9239 adjustment function according to Table 13.
Table 12. NI 9229/9239 Verification Test Limits for Phase Matching
Module
Generator Frequency
(kHz) Phase Matching Channel-to-Channel Limit
NI 9229 1±0.045°
20 ±0.900°
NI 9239 1±0.075°
20 ±1.500°

10 |ni.com |NI 9229/9239 Calibration Procedure
g. Set the calibrator to Standby mode (STBY).
h. Repeat steps d through g for each calibration voltage in the array.
i. Close the calibration session.
4. Disconnect the NI 9229/9239 from the calibrator.
EEPROM Update
When an adjustment procedure is completed, the NI 9229/9239 internal calibration memory
(EEPROM) is immediately updated.
If you do not want to perform an adjustment, you can update the calibration date and onboard
calibration temperature without making any adjustments by initializing an external calibration,
setting the C Series calibration temperature, and closing the external calibration.
Reverification
Repeat the Verification section to determine the As-Left status of the device.
Note If any test fails Reverification after performing an adjustment, verify that you
have met the Test Conditions before returning your device to NI. Refer to Worldwide
Support and Services for assistance in returning the device to NI.
Accuracy Under Calibration Conditions
The following calibration specifications are valid under the following conditions:
• Ambient temperature 23 ± 5 °C
• NI 9229/9239 installed in slot 8 of an NI cDAQ-9178 chassis
• Slots 1 through 7 of the NI cDAQ-9178 chassis are empty
Note The test limits listed in Table 4 are derived using the values in Table 14.
Table 13. Adjustment Configuration
Physical Channel Reference Value
cDAQMod8/aixThe reference value from the array of adjustment points
Table 14. NI 9229/9239 Accuracy Under Calibration Conditions
Module Gain Error Offset Error
NI 9229 ±0.04% ±7.66 mV
NI 9239 ±0.04% ±1.35 mV