CALIBRATION PROCEDURE
NI 9266
8-Channel C Series Current Output Module
This document contains the verification and adjustment procedures for the NI 9266. For more
information on calibration solutions, visit ni.com/calibration.
Software
Calibrating the NI 9266 requires the installation of NI-DAQmx 18.1 or later on the calibration
system.
You can download NI-DAQmx from ni.com/downloads. NI-DAQmx supports LabVIEW,
LabWindows™/CVI™, ANSI C, and .NET. When you install NI-DAQmx, you only need to
install support for the application software that you intend to use.
Documentation
Consult the following documents for information about the NI 9266, 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 9266 Getting Started Guide
NI 9266 connection information
NI 9266 Datasheet
NI 9266 circuitry and specifications
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
Test Equipment
NI recommends that you use equipment in the following table for calibrating the NI 9266. If
the recommended equipment is not available, select a substitute from the requirements
column.
Equipment Recommended
Model
DMM NI 4070 DMM Use a multi-ranging 6 1/2 digit DMM with a
DC current measurement accuracy of
Chassis cDAQ-9178 —
Bench-Top Power
Supply
— 9 V DC to 30 V DC output voltage with an
Requirements
400 ppm.
output rated for at least 5 W.
Test Conditions
The following setup and environmental conditions are required to ensure the NI 9266 meets
calibration specifications.
• Keep connections to the NI 9266 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 9266 are secure.
• Use shielded copper wire for all cable connections to the NI 9266. Use twisted-pairs wire
to eliminate noise and thermal offsets.
• Maintain an ambient temperature of 23 °C ± 5 °C. The NI 9266 temperature will be
greater than the ambient temperature.
• Keep relative humidity below 80%.
• Allow a warm-up time of at least 10 minutes to ensure that the NI 9266 measurement
circuitry is at a stable operating temperature.
2 | ni.com | NI 9266 Calibration Procedure
Initial Setup
NI 9266
DMM
HI
LO
Power Supply
+
–
COMx
AOx
Power Supply COM
Vsup
Complete the following steps to set up the NI 9266.
1. Install NI-DAQmx.
2. Make sure that the cDAQ-9178 power source is not connected to the chassis.
3. Insert the module in slot 8 of the cDAQ-9178 chassis. Leave slots 1 through 7 of the
cDAQ-9178 chassis empty.
4. Connect the cDAQ-9178 chassis to your host computer.
5. Connect the power source to the cDAQ-9178 chassis.
6. Launch Measurement & Automation Explorer (MAX).
7. Right-click the device name and select Self-Test to ensure that the module is working
properly.
Verification
The following performance verification procedure describes the sequence of operation and
provides test points required to verify the NI 9266. The verification procedure assumes 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 9266.
1. Set the DMM to Standby mode (STBY) and disable the output of the bench-top power
supply.
2. Connect the NI 9266 to the bench-top power supply and the DMM as shown in the
following figure.
Figure 1. Current Accuracy Connections
3. Enable the output of the bench-top power supply.
NI 9266 Calibration Procedure | © National Instruments | 3
4. Set the DMM to read DC current in the 20 mA range and select the following settings.
– ≥1 PLC
– Auto Zero
– ADC calibration enabled
5. Acquire a sample.
a. Create and configure an AO task according to the following table.
Table 1. NI 9266 Configuration for Current Accuracy Verification
Range
Scaled Units Custom ScaleMinimum Maximum
0 0.02 Amps None
b. Start the task.
c. Generate a current output test point by writing a single sample according to the
following table.
Table 2. NI 9266 Test Limits and Output Data Configuration for Current Accuracy
Verification
Test Point Value
(mA)
Lower Limit (mA) Upper Limit (mA)
1-Year Limits Samples Per
Channel
Timeout
1 0.97027 1.02973
19 18.95101 19.04899
The test limits in this table are derived from the values listed in Accuracy under Calibration
Conditions.
d. Wait the appropriate amount of time for the DMM measurement to settle.
e. Read the NI 9266 output current measurement from the DMM.
f. Clear the task.
6. Compare the DMM measurement to the test limits in the table above.
7. Repeat step 5 for each test point in the table above.
8. Disconnect the DMM and bench-top power supply from the NI 9266.
9. Repeat steps 1 through 7 for each channel on the NI 9266.
1 10.0
Adjustment
The following performance adjustment procedure describes the sequence of operation required
to adjust the NI 9266.
Accuracy Adjustment
Complete the following procedure to adjust the accuracy of the NI 9266.
1. Adjust the NI 9266.
a) Initialize a calibration session on the NI 9266. The default password is NI.
4 | ni.com | NI 9266 Calibration Procedure
b) Input the external temperature in degrees Celsius.
c) Call the NI 9266 get C Series adjustment points function to obtain an array of
recommended calibration currents for the NI 9266.
d) Connect the DMM and the bench-top power supply to the NI 9266 as shown in the
Current Accuracy Connections figure.
e) Set the DMM to read DC current in the 20 mA range.
f) Call and configure the NI 9266 setup calibration function with the DAC value
obtained from the array of recommended calibration currents.
g) Wait the appropriate amount of time for the DMM measurement to settle.
h) Read the NI 9266 output current measurement from the DMM.
i) Call and configure the NI 9266 adjustment function according to the following table.
Physical Channel Reference Value
cDAQMod8/aox The NI 9266 output current measured from the DMM.
j) Repeat steps f through i for each calibration current in the array.
k) Close the calibration session.
l) Disconnect the DMM from the NI 9266.
2. Repeat step 1 for each channel on the NI 9266.
EEPROM Update
When an adjustment procedure is completed, the NI 9266 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 Accuracy 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 values in the following table are based on calibrated scaling coefficients, which are stored
in the onboard EEPROM.
NI 9266 Calibration Procedure | © National Instruments | 5
The following accuracy table is valid for calibration under the following conditions:
• Ambient temperature 23 °C ± 5 °C
• NI 9266 installed in slot 8 of a cDAQ-9178 chassis
• Slots 1 through 7 of the cDAQ-9178 chassis are empty
Table 3. NI 9266 Accuracy under Calibration Conditions
Device Percent of Reading (Gain Error) Percentage of Range (Offset Error)
1
NI 9266 0.107% 0.138%
Note For operational specifications, refer to the most recent NI 9266 Datasheet
online at ni.com/manuals.
Worldwide Support and Services
The NI website is your complete resource for technical support. At ni.com/support, you have
access to everything from troubleshooting and application development self-help resources to
email and phone assistance from NI Application Engineers.
Visit ni.com/services for information about the services NI offers.
Visit ni.com/register to register your NI product. Product registration facilitates technical
support and ensures that you receive important information updates from NI.
NI corporate headquarters is located at 11500 North Mopac Expressway, Austin, Texas,
78759-3504. NI also has offices located around the world. For support in the United States,
create your service request at ni.com/support or dial 1 866 ASK MYNI (275 6964). For
support outside the United States, visit the Worldwide Offices section of ni.com/niglobal to
access the branch office websites, which provide up-to-date contact information.
1
Range equals 20.77.
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© 2019 National Instruments. All rights reserved.
377587A-01 May 3, 2019
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