National Instruments 9220 Manual

CALIBRATION PROCEDURE
NI 9220
This document contains the verification and adjustment procedures for the National
Instruments 9220. In this document, the NI 9220 with spring terminal and the NI 9220 with
DSUB are referred to inclusively as the NI 9220. For more information about calibration
solutions, visit ni.com/calibration.
Contents
Software Requirements............................................................................................................. 2
Documentation.......................................................................................................................... 2
Test Equipment......................................................................................................................... 3
Test Conditions......................................................................................................................... 3
Initial Setup............................................................................................................................... 3
Verification ............................................................................................................................... 4
Accuracy Verification....................................................................................................... 4
Adjustment................................................................................................................................ 5
Accuracy Adjustment ....................................................................................................... 5
EEPROM Update ..................................................................................................................... 6
Re-Verification ......................................................................................................................... 6
Accuracy Under Calibration Conditions .................................................................................. 7
Where to Go for Support .......................................................................................................... 7
ni.com/manuals
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2|ni.com |NI 9220 Calibration Procedure
Software Requirements
Calibrating the NI 9220 requires the installation of NI-DAQmx 9.6 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 9220, NI-DAQmx, and your
application software. All documents are available on ni.com and help files install with the
software.
NI cDAQ-9174/9178 Quick Start
NI-DAQmx installation and hardware setup
NI 9220 User Guide and Specifications
NI 9220 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 9220 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 9220 meets
published specifications.
• Keep connections to the NI 9220 as short as possible. Long cables and wires act as
antennae, picking up extra noise that can affect measurements.
• Verify that all connections to the NI 9220 are secure.
• Use shielded copper wire for all cable connections to the NI 9220. 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 9220 measurement
circuitry is at a stable operating temperature.
Initial Setup
Complete the following steps to set up the NI 9220.
1. Install NI-DAQmx.
2. Make sure the NI cDAQ-9178 power source is not connected.
3. Install the module in slot 8 of the NI cDAQ-9178 chassis. Leave slots 1 through 7 of the
NI cDAQ-9178 chassis empty.
4. Connect the NI cDAQ-9178 chassis to your host computer.
5. Connect the power source to the NI 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.
Table 1. Recommended Equipment
Equipment
Recommended
Model Requirements
Calibrator Fluke 5700A Use a high-precision voltage source with an
accuracy of ≤15 ppm and an output impedance
of ≤50 Ω.
Chassis NI cDAQ-9178 —
DSUB Connection
Accessory
NI 9923 —

4|ni.com |NI 9220 Calibration Procedure
Verification
The following performance verification procedure describes the sequence of operation and test
points required to check the NI 9220 and 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 9220.
1. Set the calibrator to Standby mode (STBY).
2. Connect the NI 9220 to the calibrator as shown in Figure 1.
Figure 1. Accuracy Verification Connections
Note If the calibrator outputs are truly floating, connect the negative output to a
quiet earth ground as well as COM to give the entire system a ground reference.
3. Set the calibrator voltage to a Test Point value indicated in Table 4.
4. Set the calibrator to Operate mode (OPR).
5. Acquire and average samples.
a. Create and configure an AI voltage channel according to Table 2.
1 Connections when using a calibrator with a guard connection.
2 Connections when using a calibrator with no guard connection.
Table 2. NI 9220 AI Voltage Channel Configuration
Input Range
Scaled Units Terminal ConfigurationMin Max
-10 10 Vo l t s Differential
NI 9220Calibrator
AIx–
AIx+
COM
HI
LO
Guard
NI 9220Calibrator
AIx–
AIx+
COM
HI
LO
12

NI 9220 Calibration Procedure |© National Instruments |5
b. Configure the AI voltage channel timing according to Table 3.
c. Start the task.
d. Read samples from the NI 9220.
e. Average the samples.
f. Clear the task.
6. Compare the average of the samples to the test limits in Table 4.
Note The test limits listed in Table 4 are derived using the values in Table 6.
7. Repeat steps 3 through 6 for each Test Point in Table 4.
8. Set the calibrator to Standby mode (STBY).
9. Disconnect the NI 9220 from the calibrator.
10. Repeat steps 1 through 9 for each channel on the NI 9220.
Adjustment
The following performance adjustment procedure describes the sequence of operation required
to adjust the NI 9220.
Accuracy Adjustment
Complete the following procedure to adjust the accuracy performance of the NI 9220.
1. Set the calibrator to Standby mode (STBY).
2. Connect the NI 9220 to the calibrator as shown in Figure 1.
3. Adjust the NI 9220.
a. Initialize a calibration session on the NI 9220. The default password is NI.
b. Input the external temperature in degrees Celsius.
Table 3. NI 9220 Timing Configuration
Samples Per Channel Acquisition Mode Rate (kS/s)
10,000 Finite 100
Table 4. NI 9220 Test Limits
Range (V) Test Point 1-Year Limits
Min Max Location Value (V) Lower Limit (V) Upper Limit (V)
-10.000 10.000 Max 9.500000 9.498485 9.501515
-10.000 10.000 Mid 0.000000 -0.00028 0.00028
-10.000 10.000 Min -9.500000 -9.501515 -9.498485

6|ni.com |NI 9220 Calibration Procedure
c. Call the NI 9220 get C Series adjustment points function to obtain an array of
recommended calibration voltages for the NI 9220.
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 9220 adjustment function according to Table 5.
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 9220 from the calibrator.
5. Repeat steps 1 through 4 for each channel on the NI 9220.
EEPROM Update
When an adjustment procedure is completed, the NI 9220 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.
Re-Verification
Repeat the Verification section to determine the As-Left status of the device.
Note If any test fails Re-Verification after performing an adjustment, verify that
you have met the Test Conditions before returning your device to NI. Refer to Where
to Go for Support section for assistance in returning the device to NI.
Table 5. Adjustment Configuration
Physical Channel Reference Value
cDAQMod8/aixThe reference value from the array of adjustment points

© 2012 National Instruments. All rights reserved.
372220A-01 Oct12
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Accuracy Under Calibration Conditions
The following calibration specifications are valid under the following conditions:
• Ambient temperature 23 ±5 °C
• NI 9220 installed in slot 8 of an NI cDAQ-9178 chassis
• Slots 1 through 7 of the NI cDAQ-9178 chassis are empty
Note The limits listed in Table 4 are derived using the values in Table 6.
Note For operational specifications, refer to the most recent NI 9220 User Guide
and Specifications online at ni.com/manuals.
Where to Go for Support
The National Instruments Web site 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.
National Instruments corporate headquarters is located at 11500 North Mopac Expressway,
Austin, Texas, 78759-3504. National Instruments also has offices located around the world to
help address your support needs. For telephone support in the United States, create your service
request at ni.com/support and follow the calling instructions or dial 512 795 8248. For
telephone support outside the United States, visit the Worldwide Offices section of ni.com/
niglobal to access the branch office Web sites, which provide up-to-date contact information,
support phone numbers, email addresses, and current events.
Table 6. NI 9220 Accuracy Under Calibration Conditions
Gain Error Offset Error
0.013% 0.28 mV