National Instruments WSN-3226 Manual

CALIBRATION PROCEDURE
NI WSN-3226
NI Wireless Sensor Network 4-Channel, 20-Bit Voltage/RTD Node
This document contains the verification procedures for the National Instruments WSN-3226.
For more information about calibration solutions, visit ni.com/calibration.
Contents
Software.................................................................................................................................... 1
Documentation.......................................................................................................................... 1
Test Equipment......................................................................................................................... 2
Test Conditions......................................................................................................................... 2
Initial Setup............................................................................................................................... 3
Verification ............................................................................................................................... 3
Voltage Accuracy Verification......................................................................................... 3
Resistance Accuracy Verification .................................................................................... 5
Re-Verification ......................................................................................................................... 6
Accuracy Under Calibration Conditions .................................................................................. 6
Where to Go for Support .......................................................................................................... 7
Software
Calibrating the NI WSN-3226 requires the installation of LabVIEW 2010 or later and
NI-WSN 1.2 or later on the calibration system. You can download NI-WSN from ni.com/
downloads.
Documentation
Consult the following documents for information about the NI WSN-3226, NI-WSN, and
LabVIEW. All documents are available on ni.com and help files install with the software.
NI Wireless Sensor Network Devices Getting Started Guide
NI-WSN installation and hardware setup
NI WSN-3226 User Guide and Specifications
NI WSN-3226 specific information, specifications, and calibration interval

2|ni.com |NI WSN-3226 Calibration Procedure
Test Equipment
Table 1 lists the equipment recommended for the performance verification procedures. If the
recommended equipment is not available, select a substitute using the requirements listed in
Table 1.
Test Conditions
Follow these guidelines to optimize the equipment and the environment during calibration:
•FortheResistance Accuracy Verification procedure, keep connections to the
NI WSN-3226 under 5 inches and within 1/8 inch in length of each other.
• Verify that all connections to the device are secure.
• The NI WSN-3226 must be powered by either an external 9 V to 30 V power supply or
four AA (1.5 V) batteries (alkaline only).
LabVIEW Help
LabVIEW programming concepts and reference information about NI-WSN VIs
and functions
Table 1. Recommended Equipment
Equipment
Recommended
Model
Where
Used Requirements
Calibrator Fluke 5520A Voltage Use a high-precision voltage
source with an accuracy of at least
50 ppm and an output impedance
of ≤1 Ω
Resistance Use a high-precision resistance
calibrator with an accuracy of at
least 90 ppm
WSNEthernet
gateway and
power supply
NI WSN-9791 with
9 V to 30 V power
supply
All —
NI 9792 with 9 V to
35 V power supply
NI 9795 with
CompactRIO
system
Screw
terminal
wiring
—All 14 to 24 AWG wire

NI WSN-3226 Calibration Procedure |© National Instruments |3
• Maintain an ambient temperature of 23 °C ± 5 °C.
• Keep relative humidity between 10% and 90%.
• Allow a warm-up time for all the instruments and equipment, according to the
manufacturers’ instructions.
Initial Setup
Refer to the NI Wireless Sensor Network Devices Getting Started Guide for information about
how to install the software and hardware and how to configure the device in Measurement &
Automation Explorer (MAX).
Verification
The following performance verification procedures describe the sequence of operation and test
points required to verify the NI WSN-3226 and assume that adequate traceable uncertainties are
available for the calibration references.
Voltage Accuracy Verification
Complete the following procedure to determine the As-Found status of the NI WSN-3226.
1. Connect the calibrator to the NI WSN-3226 as shown in Figure 1.
Figure 1. NI WSN-3226 Voltage Connections
2. Configure a project for the WSN system in LabVIEW.
3. Right-click the NI WSN-3226 in the Project Explorer and select Properties to launch the
Properties dialog box.
Calibrator
NI WSN-3226
COM 3
AI 3
COM 2
AI 2
COM 1
AI 1
COM 0
AI 0
LO
HI

4|ni.com |NI WSN-3226 Calibration Procedure
4. Configure the NI WSN-3226 according to Table 2.
5. Click OK.
6. Right-click the NI WSN-3226 in the Project Explorer and select Deploy.
7. Set the calibrator to a Test Point value indicated in Table 3.
8. Create a VI in LabVIEW to acquire a voltage reading from the AI 0 variable on the
NI WSN-3226.
9. Acquire and average 25 voltage readings with the NI WSN-3226.
10. Compare the average of the NI WSN-3226 readings with the 3-Year Limits in Table 3.
11. Repeat steps 7 through 10 for all test points in Table 3.
Note The limits in Table 3 are derived using the values in Table 6.
If the Voltage Accuracy verification procedure determines that the NI WSN-3226 is outside of
the limits, refer to Where to Go for Support for assistance in returning the device to NI.
Table 2. NI WSN-3226 Voltage Configuration
Channel
Attribute*
Channel
Value*
Sample
Interval
Powerline
Filtering
Filtering
Strength
Measurement
Type
Vo l t a g e 150/60 Hz High Rejection
* Set the channel attribute and value for each analog input channel.
Table 3. NI WSN-3226 Voltage Test Limits
Range (V) Test Point 3-Year Limits
Positive
Full Scale
Negative
Full Scale
Value
(V)
Lower Limit
(V)
Upper Limit
(V)
10.000 -10.000 9.95000 9.94332 9.95668
0.00000 -0.0027 0.0027
-9.95000 -9.95668 -9.94332

NI WSN-3226 Calibration Procedure |© National Instruments |5
Resistance Accuracy Verification
Complete the following procedure to determine the As-Found status of the NI WSN-3226.
1. Connect the calibrator to the NI WSN-3226 as shown in Figure 2.
Figure 2. NI WSN-3226 Resistance Connections
2. Configure a project for the WSN system in LabVIEW.
3. Right-click the NI WSN-3226 in the Project Explorer and select Properties to launch the
Properties dialog box.
4. Configure the NI WSN-3226 according to Table 4.
5. Click OK.
6. Right-click the NI WSN-3226 in the Project Explorer and select Deploy.
7. Set the calibrator to a Test Point value indicated in Table 5 that corresponds to the
appropriate RTD/resistance range.
8. Turn any connection compensation settings on the calibrator off.
Tip On the Fluke 5520A, press the COMP softkey to turn compensation off.
9. Create a VI in LabVIEW to acquire a voltage reading from the AI 0 variable on the
NI WSN-3226.
10. Acquire and average 25 voltage readings with the NI WSN-3226.
11. Compare the average of the NI WSN-3226 readings with the 3-Year Limits in Table 5.
12. Repeat steps 7 through 11 for all test points and all RTD/resistance ranges in Table 5.
13. Disconnect the calibrator from the NI WSN-3226.
Table 4. NI WSN-3226 Resistance Configuration
Channel
Attribute
Channel
Value
Sample
Interval
Powerline
Filtering
Filtering
Strength
RTD/Resistance
Range
Measurement
Type
Resistance 150/60 Hz High
Rejection
400 Ω/Pt100
4 kΩ/Pt1000
100 kΩ
Calibrator NI WSN-3226
COM
AI
EX
CHx
LO
HI

6|ni.com |NI WSN-3226 Calibration Procedure
14. Repeat steps 1 through 13 for each channel on the NI WSN-3226.
Note The limits in Table 5 are derived using the values in Table 7.
If the Resistance Accuracy verification procedure determines that the NI WSN-3226 is outside
of the limits, refer to Where to Go for Support for assistance in returning the device to NI.
Re-Verification
Repeat the Verification section to determine the As-Left status of the device.
Accuracy Under Calibration Conditions
The values in the following tables 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 of 23 °C ± 5 °C
• Relative humidity between 10% and 90%
Table 5. NI WSN-3226 Resistance Test Limits
RTD/Resistance
Range Setting Test Point (Ω)
3-Year Ranges
Lower Limit (Ω)Upper Limit (Ω)
400 Ω/Pt100 100 99.893 100.107
390 389.777 390.223
4 kΩ/Pt1000 1000 999.26 1000.74
4020 4018.35 4021.65
100 kΩ4020 4011.39 4028.21
100000 99963 100037
Table 6. NI WSN-3226 Voltage Accuracy
Range Gain (% of Reading) Offset (mV)
10 V 0.04 2.70

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373252A-01 Jul13
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Note The limits in Table 3 are derived using the values in Table 6.
Note The limits in Table 5 are derived using the values in Table 7.
Note For operational specifications, refer to the most recent NI WSN-3226 User
Guide and Specifications online at ni.com/manuals.
Where to Go for Support
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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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Table 7. NI WSN-3226 Resistance Accuracy
RTD/Resistance Range Gain (% of Reading) Offset (Ω)
400 Ω/Pt100 0.04 0.067
4 kΩ/Pt1000 0.03 0.440
100 kΩ0.04 7.000