National Instruments NI 9246 Manual

CALIBRATION PROCEDURE
NI 9246/9247
This document contains the verification and adjustment procedures for the NI 9246 and NI 9247.
For more information about calibration solutions, visit ni.com/calibration.
Contents
Software.................................................................................................................................... 1
Documentation.......................................................................................................................... 2
Test Equipment......................................................................................................................... 3
Test Conditions......................................................................................................................... 3
Initial Setup............................................................................................................................... 3
Verification ............................................................................................................................... 4
Accuracy Verification....................................................................................................... 4
Adjustments .............................................................................................................................. 6
Accuracy Adjustment ....................................................................................................... 6
EEPROM Update ..................................................................................................................... 6
Reverification ........................................................................................................................... 7
Worldwide Support and Services ............................................................................................. 7
Software
Calibrating the NI 9247 requires the installation of NI-DAQmx 15.1 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.

2|ni.com |NI 9246/9247 Calibration Procedure
Documentation
Consult the following documents for information about the NI 9246/9247, 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 9246 Getting Started Guide
NI 9246 specific information.
NI 9246 Datasheet
NI 9246 specifications and calibration interval.
NI 9247 Getting Started Guide
NI 9247 specific information.
NI 9247 Datasheet
NI 9247 specifications and calibration interval.
NI DAQmx Readme
Operating system and application software support.
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 9246/9247 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 9246/9247
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 °C ± 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 9246/9247 measurement
circuitry is at a stable operating temperature.
Initial Setup
Complete the following steps to set up the NI 9246/9247.
1. Install NI-DAQmx.
2. Make sure the NI cDAQ-9178 power source is not connected to the chassis.
3. Connect the NI cDAQ-9178 chassis 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 chassis
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.
Table 1. Recommended Equipment
Equipment
Recommended
Model
Parameter
Measured Requirements
Source Fluke 5522A Accuracy,
Adjustment
Use a high-precision current
source with an accuracy
≤650 ppm
cDAQ Chassis NI cDAQ-9178 All —

4|ni.com |NI 9246/9247 Calibration Procedure
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 procedures describe the sequence of operation and test
points required to verify the NI 9246/9247 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 9246/9247.
1. Set the calibrator to Standby mode (STBY).
2. Connect the NI 9246/9247 to the calibrator as shown in Figure 1.
Figure 1. Accuracy Verification Connections
3. Set the calibrator current to a Test Point Value indicated in Table 4.
4. Set the calibrator to Operate mode (OPR).
5. Wait at least 45 seconds for the signal to settle.
6. Acquire samples from each channel.
a. Create and configure an AI current task on the NI 9246/9247 according to Table 2.
Table 2. NI 9246/9247Configuration for Accuracy Verification
Min Max Scaled Units Physical Channels
NI 9246 -31.25 31.25 Current AI0:2
NI 9247 -147 147 Current AI0:2
NI 9246/9247
Calibrator
HI
LO
AI1
–
+
AI0
–
+
AI2
–
+

NI 9246/9247 Calibration Procedure |© National Instruments |5
b. Configure the AI current task according to Table 3.
c. Start the task.
d. For the maximum Test Point calculate and record the AC magnitude for each channel
on the NI 9246/9247. NI recommends using the Extract Single Tone Information VI
to calculate the magnitude. For the minimum test point average the value and record
the result.
Note The output magnitude of the Extract Single Tone Information is in Apk. To
convert to RMS, use the following equation:
e. Stop and clear the task.
7. Compare the average for each channel to the limits in Table 4.
Note The test limits listed in Table 4 should be used for calibration verification
only. These values only apply under the specific calibration conditions described in
this document, and are not to be construed as general operational specification of the
NI 9246/9247. For operation specification, refer to the most recent NI 9246
Datasheet and NI 9247 Datasheet at ni.com/manual.
8. Set the calibrator to Standby mode (STBY).
9. Repeat steps 3 through 7 for each test point listed in Table 4.
10. Disconnect the calibrator from the device.
Table 3. NI 9246/9247 Timing Configuration
Sample Mode Samples Per Channel Sample Rate (kS/s)
Finite Samples 50,000 50
Table 4. NI 9246/9247 Verification Test Limits for Accuracy
Test Point 1-Year Limits
Location Value
Frequency
(Hz) Lower Limit Upper Limit
NI 9246
Max 2 Arms 55 1.9913 Arms 2.0087 Arms
Min 0.00 Adc 0.00 -0.023 Adc 0.023 Adc
NI 9247
Max 2 Arms 55 1.9925 Arms 2.0075 Arms
Min 0.00 Adc 0.00 -0.133 Adc 0.133 Adc
Arms Apk() 2()÷=

6|ni.com |NI 9246/9247 Calibration Procedure
Adjustments
The following performance adjustment procedure describes the sequence of operation required
to adjust the NI 9246/9247.
Accuracy Adjustment
Complete the following procedure to adjust the accuracy performance of the NI 9246/9247.
1. Set the calibrator to Standby mode (STBY).
2. Connect the NI 9246/9247 to the calibrator as shown in Figure 1.
3. Adjust the NI 9246/9247.
a. Initialize a calibration session on the NI 9246/9247. The default password is NI.
b. Input the external temperature in degrees Celsius.
c. Call the NI 9246/9247 DAQmx Get C Series Calibration Adjustment Points function
to obtain an array of recommended calibration current for the NI 9246/9247.
d. Set the calibrator to a reference value determined by the array of recommended
calibration currents.
e. Set the calibrator’s output frequency to 55 Hz.
f. Set the calibrator to Operate mode (OPR).
g. Wait at least 45 seconds for the signal to settle.
h. Call and configure the NI 9246/9247 adjustment function according to Table 5.
Note To adjust all channels in parallel, use ‘ai0:2’ as the channel name.
i. Set the calibrator to Standby mode (STBY).
j. Close and commit the calibration session.
4. Disconnect the NI 9246/9247 from the calibrator.
EEPROM Update
When an adjustment procedure is completed, the NI 9246/9247 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.
Table 5. Adjustment Configuration
Physical Channel Reference Value
cDAQMod8/aixThe reference value from the array of adjustment points

© 2016 National Instruments. All rights reserved.
375305A-01 Aug16
Refer to the NI Trademarks and Logo Guidelines at ni.com/trademarks for more information on National Instruments trademarks. Other
product and company names mentioned herein are trademarks or trade names of their respective companies. For patents covering National
Instruments products/technology, refer to the appropriate location: Help»Patents in your software, the patents.txt file on your media, or the
National Instruments Patents Notice at ni.com/patents. You can find information about end-user license agreements (EULAs) and third-party
legal notices in the readme file for your NI product. Refer to the Export Compliance Information at ni.com/legal/export-compliance
for the National Instruments global trade compliance policy and how to obtain relevant HTS codes, ECCNs, and other import/export data. NI MAKES
NO EXPRESS OR IMPLIED WARRANTIES AS TO THE ACCURACY OF THE INFORMATION CONTAINED HEREIN AND SHALL NOT BE LIABLE FOR
ANY ERRORS. U.S. Government Customers: The data contained in this manual was developed at private expense and is subject to the applicable
limited rights and restricted data rights as set forth in FAR 52.227-14, DFAR 252.227-7014, and DFAR 252.227-7015.
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.
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 NI Factory Installation Services, repairs, extended warranty, and
other services.
Visit ni.com/register to register your NI product. Product registration facilitates technical
support and ensures that you receive important information updates from NI.
A Declaration of Conformity (DoC) is our claim of compliance with the Council of the European
Communities using the manufacturer’s declaration of conformity. This system affords the user
protection for electromagnetic compatibility (EMC) and product safety. You can obtain the DoC
for your product by visiting ni.com/certification. If your product supports calibration,
you can obtain the calibration certificate for your product at ni.com/calibration.
NI corporate headquarters is located at 11500 North Mopac Expressway, Austin, Texas,
78759-3504. NI also has offices located around the world. For telephone support in the United
States, create your service request at ni.com/support or dial 1 866 ASK MYNI (275 6964).
For telephone 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, support phone numbers, email addresses, and current events.