National Instruments 9211 Manual

CALIBRATION PROCEDURE
NI 9211
This document contains the verification and adjustment procedures for the National Instruments
9211. For more information about calibration solutions, visit ni.com/calibration.
Contents
Software.................................................................................................................................... 1
Documentation.......................................................................................................................... 2
Test Equipment......................................................................................................................... 2
Test Conditions......................................................................................................................... 3
Initial Setup............................................................................................................................... 3
Verification ............................................................................................................................... 3
Accuracy Verification....................................................................................................... 4
Adjustment................................................................................................................................ 5
Accuracy Adjustment ....................................................................................................... 5
EEPROM Update ..................................................................................................................... 6
Re-Verification ......................................................................................................................... 6
Accuracy Under Calibration Conditions .................................................................................. 6
Where to Go for Support .......................................................................................................... 7
Software
Calibrating the NI 9211 requires the installation of NI-DAQmx 9.2 or later on the calibration
system. You can download NI-DAQmx from ni.com/downloads. NI-DAQmx supports
LabVIEW, LabWindows™/CVI™, C++, and .NET. When you install NI-DAQmx, you only need
to install support for the application software that you intend to use.

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Documentation
Consult the following documents for information about the NI 9211, NI-DAQmx, and your
application software. All documents are available on ni.com and help files install with the
software.
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.
NI cDAQ-9174/9178 Quick Start
NI-DAQmx installation and hardware setup
NI 9211 Operating Instructions and Specifications
NI 9211 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
Table 1. Recommended Equipment
Equipment Recommended Model Requirements
Calibrator Fluke 5520A locked in
the 3.3 V range
A high-precision voltage source with ≤7μV of
uncertainty at 75 mV and ≤2μV of uncertainty
at 0 V and an output impedance <5 Ω.
Chassis NI cDAQ-9178 —
Connection
Accessory
NI 9932 —

NI 9211 Calibration Procedure |© National Instruments Corporation |3
Test Conditions
The following setup and environmental conditions are required to ensure the NI 9211 meets
published specifications.
• Keep connections to the NI 9211 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 9211 are secure.
• Use shielded copper wire for all cable connections to the NI 9211. 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 9211 measurement
circuitry is at a stable operating temperature.
Initial Setup
Complete the following steps to set up the NI 9211.
1. Install NI-DAQmx.
2. Make sure the NI cDAQ-9178 power source is not connected.
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 module 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 Measurement & Automation Explorer (MAX).
8. 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 test
points required to verify the NI 9211 and assumes that adequate traceable uncertainties are
available for the calibration references.

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Accuracy Verification
Complete the following procedure to determine the As-Found status of the NI 9211.
1. Set the calibrator to Standby mode (STBY).
2. Connect the NI 9211 to the calibrator as shown in Figure 1.
Figure 1. Accuracy Verification Connections
3. Set the calibrator output 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.
b. Configure the AI voltage channel timing according to Table 3.
c. Start the task.
d. Read samples from the NI 9211.
e. Average the samples for each channel.
f. Clear the task.
Table 2. NI 9211 AI Voltage Channel Configuration
Input Terminal
Configuration
Minimum
Value (V)
Maximum
Value (V)
Physical
Channels Units Autozero
Differential -0.08 0.08 cDAQMod8/ai0:3 Volts Every
Sample
Table 3. NI 9211 Timing Configuration
Samples Per Channel Sample Mode Rate (S/s)
100 Finite 7
Calibrator
NI 9211
TC3–
COM
TC3+
TC2–
TC2+
TC1–
TC1+
TC0–
TC0+
LO
HI
Guard

NI 9211 Calibration Procedure |© National Instruments Corporation |5
6. Compare the average sample for each channel to the test limits in Table 4.
Note The test limits listed in Table 4 are derived using the values in Table 6.
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 NI 9211.
Adjustment
The following performance adjustment procedure describes the sequence of operation required
to adjust the NI 9211.
Accuracy Adjustment
Complete the following procedure to adjust the accuracy performance of the NI 9211.
1. Set the calibrator to Standby mode (STBY).
2. Connect the NI 9211 to the calibrator as shown in Figure 1.
3. Set the calibrator output to 0.07 V.
4. Set the calibrator to Operate mode (OPR).
5. Adjust the NI 9211.
a. Open a calibration session on the NI 9211.
b. Input the external temperature in degrees Celsius.
c. Call and configure the NI 9211 adjustment function according to Table 5.
d. Close the calibration session.
6. Set the calibrator to Standby mode (STBY).
7. Disconnect the calibrator from the NI 9211.
Table 4. NI 9211 Test Limits
Test Point 1-Year Limits
Location Value (V) Lower Limit (V) Upper Limit (V)
Max 0.075000 0.074959 0.075041
Mid 0-0.000013 0.000013
Min -0.075000 -0.075041 -0.074959
Table 5. Adjustment Configuration
Physical Channels Reference Value
cDAQMod8/ai0:3 0.07

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EEPROM Update
When an adjustment procedure is completed, the NI 9211 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 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.
The following accuracy table is valid for calibration under the following conditions:
• Ambient temperature 23 °C ±5 °C
• NI 9211 installed in slot 8 of an NI cDAQ-9178 chassis
• Slots 1 through 7 of the NI cDAQ-9178 chassis are empty
Note For operational specifications, refer to the most recent NI 9211 Operating
Instructions/User Guide and Specifications online at ni.com/manuals.
Table 6. NI 9211 Accuracy Under Calibration Conditions
Gain Error Offset Error
370 ppm 13 μV

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372137B-01 Mar13
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