NI 9207 Calibration Procedure

CALIBRATION PROCEDURE
NI 9207
16-channel, ±2- mA/±10 V, 24-bit Analog Input Module
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This document contains the verification and adjustment procedures for the National
Instruments 9207. 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
Voltage Accuracy Verification......................................................................................... 4
Current Accuracy Verification ......................................................................................... 5
Adjustments .............................................................................................................................. 7
Voltage Accuracy Adjustment.......................................................................................... 7
Current Accuracy Adjustment .......................................................................................... 8
EEPROM Update ..................................................................................................................... 8
Reverification ........................................................................................................................... 9
Accuracy Under Calibration Conditions .................................................................................. 9
Worldwide Support and Services ............................................................................................. 10
Software
Calibrating the NI 9207 requires the installation of NI-DAQmx 9.1 or later on the calibration
system. You can download NI-DAQmx from ni.com/downloads. NI-DAQmx supports
LabVIEW, LabWindows™/CVI™, C/C++, C#, and Visual Basic .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 9207, 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 9207 Operating Instructions and Specifications
NI 9207 specific information, specifications, and calibration interval
NI DAQmx Help
Information about creating applications that use the NI-DAQmx driver
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
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.
Table 1. Recommended Equipment
2
Equipment
Recommended
Model
Source
Fluke 5700A
cDAQ Chassis
NI cDAQ-9178
—
Connection
Accessory
NI 9923
—
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NI 9207 Calibration Procedure
Minimum Requirements
Use a source with an accuracy ≤100 ppm.
Test Conditions
The following setup and environmental conditions are required to ensure the NI 9207 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 device are secure.
•
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 ± 5 °C. The device 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 9207 measurement
circuitry is at a stable operating temperature.
Initial Setup
Complete the following steps to set up the NI 9207.
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.
Verification
The following performance verification procedures describe the sequence of operation and test
points required to verify the NI 9207 and assumes that adequate traceable uncertainties are
available for the calibration references.
NI 9207 Calibration Procedure
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Voltage Accuracy Verification
Complete the following procedure to determine the As-Found status of the NI 9207.
1.
Set the calibrator to Standby mode (STBY).
2.
Connect the NI 9207 to the calibrator as shown in Figure 1.
Figure 1. Voltage Accuracy Connections
1
2
HI
AIx+
HI
AIx+
LO
AIx–
LO
AIx–
COM
Guard
Calibrator
1
2
NI 9207
Calibrator
NI 9207
Connections when using a calibrator with a guard connection.
Connections when using a calibrator with no guard connection.
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 task on the NI 9207 according to Table 2.
Table 2. NI 9207 Configuration for Voltage Accuracy Verification
Input Range
Min
Max
Scaled Units
Terminal Configuration
-10
10
Volts
Differential
b.
Configure the AI voltage task according toTable 3.Set the ADC timing mode to
high-resolution.
Table 3. NI 9207 Voltage Timing Configuration
ADC Timing Mode
Sample Mode
Samples to Read
High-Resolution
N Samples
5
High-Speed
N Samples
75
c.
4
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Start the task.
d.
Average the readings.
e.
Clear the task.
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NI 9207 Calibration Procedure
6.
Compare the average to the limits in Table 4.
Table 4. NI 9207 Verification Test Limits for Voltage Accuracy
Range (V)
Test Point
1-Year Limits
Minimum
Maximum
Location
Value (V)
Lower Limit
(V)
Upper Limit
(V)
-10.00000
10.00000
Pos FS
10.00000
9.98792
10.01208
-10.00000
10.00000
Mid
0.00000
-0.00208
0.00208
-10.00000
10.00000
Neg FS
-10.00000
-10.01208
-9.98792
7.
Repeat step 5 and 6 with the ADC timing mode on the NI 9207 set to high-speed.
8.
Set the calibrator to Standby mode (STBY).
9.
Repeat steps 3 through 8 for each test point listed in Table 4.
10. Disconnect the calibrator from the device.
11. Repeat steps 1 through 10 for each voltage channel on the NI 9207.
Current Accuracy Verification
Complete the following procedure to determine the As-Found status of the NI 9207.
1.
Set the calibrator to Standby mode (STBY).
2.
Connect the NI 9207 to the calibrator as shown in Figure 2.
Figure 2. Current Accuracy Connections
1
HI
LO
2
HI
AIx
COM
AIx
COM
LO
Guard
Calibrator
NI 9207
Calibrator
NI 9207
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 current to a Test Point value indicated in Table 7.
4.
Set the calibrator to Operate mode (OPR).
NI 9207 Calibration Procedure
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5.
Acquire and average samples.
a.
Create and configure an AI voltage task on the NI 9207 according to Table 5.
Table 5. NI 9207 Configuration for Current Accuracy Verification
Input Range
Min
Max
Scaled Units
Terminal Configuration
-0.02
0.02
Amps
RSE
b.
Configure the AI current task according to Table 6. Set the ADC timing mode to
high-resolution.
Table 6. Current Timing Configuration
ADC Timing Mode
Sample Mode
Samples to Read
High-Resolution
N Samples
5
High-Speed
N Samples
75
c.
Start the task.
d.
Average the readings.
e.
Clear the task.
6.
Compare the average to the limits in Table 7.
7.
Repeat steps 5 and 6 with the ADC timing mode on the NI 9207 set to high-speed.
8.
Set the calibrator to Standby mode (STBY).
9.
Repeat steps 3 through 8 for each test point in Table 7.
10. Disconnect the calibrator from the device.
11. Repeat steps 1 through 10 for each current channel on the NI 9207.
Table 7. NI 9207 Test Limits for Current Accuracy Verification
Range (A)
6
Test Point
1-Year Limits
Minimum
Maximum
Location
Value (A)
Lower Limit (A)
Upper Limit (A)
-0.020000
0.020000
Pos FS
0.021000
0.020970
0.021030
-0.020000
0.020000
Mid
0.000000
-0.000002
0.000002
-0.020000
0.020000
Neg FS
-0.021000
-0.021030
-0.020970
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NI 9207 Calibration Procedure
Adjustments
The following performance adjustment procedures describe the sequence of operation required
to adjust the NI 9207.
Voltage Accuracy Adjustment
Complete the following procedure to adjust the voltage accuracy performance of the NI 9207.
1.
Set the calibrator to Standby mode (STBY).
2.
Connect the NI 9207 to the calibrator as shown in Figure 1.
3.
Adjust the NI 9207 voltage accuracy.
a.
Initialize a calibration session on the NI 9207. The default password is NI.
b.
Input the external temperature in degrees Celsius.
c.
Call the NI 9207 get C Series adjustment points function to obtain an array of
recommended calibration voltages for the NI 9207.
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 9207 gain instance of the adjustment function according to
Table 8.
Table 8. Gain Adjustment Configuration
Physical Channel
Reference Value
cDAQMod8/aix
The reference value from the array of adjustment points
g.
Set the calibrator to Standby mode (STBY).
h.
Repeat steps d through g for each calibration voltage in the array.
i.
Disconnect the calibrator from the NI 9207.
j.
Short the voltage channel to the 9207 AIGND.
k.
Call the NI 9207 offset instance of the adjustment function for the physical channel.
l.
Close the calibration session.
4.
Remove the connections from the NI 9207.
5.
Repeat steps 1 through 4 for each voltage channel on the NI 9207.
NI 9207 Calibration Procedure
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Current Accuracy Adjustment
Complete the following procedure to adjust the current accuracy performance of the NI 9207.
1.
Set the calibrator to Standby mode (STBY).
2.
Connect the NI 9207 to the calibrator as shown in Figure 2.
3.
Adjust the NI 9207 current accuracy.
a.
Initialize a calibration session on the NI 9207. The default password is NI.
b.
Input the external temperature in degrees Celsius.
c.
Call the NI 9207 get C Series adjustment points function to obtain an array of
recommended calibration currents for the NI 9207.
d.
Set the calibrator to a reference value determined by the array of recommended
calibration currents.
e.
Set the calibrator to Operate mode (OPR).
f.
Call and configure the NI 9207 gain instance of the adjustment function according to
Table 9.
Table 9. Gain Adjustment Configuration
Physical Channel
Reference Value
cDAQMod8/aix
The reference value from the array of adjustment points
g.
Set the calibrator to Standby mode (STBY).
h.
Repeat steps d through g for each calibration current in the array.
i.
Disconnect the calibrator from the NI 9207. Ensure that there are no connections to
the NI 9207.
j.
Call the NI 9207 offset instance of the adjustment function for the current channel.
k.
Close the calibration session.
4.
Remove the connections from the NI 9207.
5.
Repeat steps 1 through 4 for each current channel on the NI 9207.
EEPROM Update
When an adjustment procedure is completed, the NI 9207 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.
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NI 9207 Calibration Procedure
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 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 9207 installed in slot 8 of an NI cDAQ-9178 chassis
•
Slots 1 through 7 of the NI cDAQ-9178 chassis are empty
The test limits listed in Tables 4 and 7 are derived using the values in
Table 10.
Note
Table 10. NI 9207 Accuracy Under Calibration Conditions
Input Channels
Percentage of Reading
Percentage of Range*
Voltage
0.100%
0.020%
Current
0.150%
0.012%
* Range
equals 10.4 V for voltage and 22 mA for current.
Note For operational specifications, refer to the most recent NI 9207 Operating
Instructions and Specifications online at ni.com/manuals.
NI 9207 Calibration Procedure
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© National Instruments
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Worldwide Support and Services
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support you have access to everything from troubleshooting and application development
self-help resources to email and phone assistance from NI Application Engineers.
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