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- What is Wi-Fi data acquisition?
- What is the difference between Wi-Fi DAQ and a wireless sensor (node)?
- What are the features of Wi-Fi DAQ devices?
- What C Series modules are supported with NI Wi-Fi DAQ?
- What kind of power does Wi-Fi DAQ require?
- Do I need a router to perform measurements with Wi-Fi DAQ?
Performance
- How fast can I acquire data?
- How many Wi-Fi DAQ devices can I use at once?
- How far can the signal travel?
- What synchronization capabilities are available with Wi-Fi DAQ?
- How long can an Ethernet cable be?
- What is isolation?
Security
Software
- How do I program Wi-Fi DAQ devices?
- What software is included with Wi-Fi DAQ devices?
- Which application development environments (ADEs) work with Wi-Fi DAQ?
Support and Services
- How do I get technical support for Wi-Fi DAQ devices?
- What warranty is provided with Wi-Fi DAQ devices?
General
What is Wi-Fi data acquisition?
Wi-Fi data acquisition is an extension of PC-based data acquisition to measurement applications where cables are inconvenient or impractical. NI Wi-Fi data acquisition (DAQ) devices combine IEEE 802.11 wireless or Ethernet communication, direct sensor connectivity, and the flexibility of NI LabVIEW software for remote monitoring of electrical, physical, mechanical, and acoustical signals. Wi-Fi DAQ introduces two new carriers for NI C Series measurement and control modules. The NI WLS-9163 is a single module C Series carrier providing both 802.11b/g and Ethernet connectivity back to a host PC, while the ENET-9163 is a single module carrier with only Ethernet connectivity. C Series modules provide direct sensor connections and built-in signal conditioning for a variety of measurements, including temperature, strain, acceleration, current, and voltage. They may be used interchangeably for a variety of measurement and control applications across several platforms, including NI CompactDAQ, CompactRIO, and a single module USB carrier. You may purchase WLS-9163 carriers and C Series modules separately or together as WLS-9xxx devices.
What is the difference between Wi-Fi DAQ and a wireless sensor (node)?
Unlike most wireless sensors or wireless sensor networks, Wi-Fi DAQ devices are meant to stream data continuously back to a host PC or laptop. A wireless sensor node is typically a low-power, semiautonomous battery-operated device intended for long-term deployment in applications where measurements are only needed every few minutes, hours, or even days. Wi-Fi DAQ devices on the other hand behave in much the same way as a USB DAQ device – a host PC collects data continuously (in real time) as it is acquired by the device. The DAQ device may be battery-operated and used in long-term applications, but the focus is on the measurement quality versus the battery life. Also, Wi-Fi DAQ uses the near-ubiquitous wireless networking standard, IEEE 802.11, instead of ZigBee or another meshing IEEE 802.15.4 variant because of its higher bandwidth and broader applicability.
What are the features of Wi-Fi DAQ devices?
Wi-Fi and Ethernet DAQ devices can each hold one C Series measurement module. The measurements, features, and specifications are defined by the type of C Series module in the WLS-9163 or ENET-9163 carrier. A standard 802.11b/g radio or IEEE 802.3 10/100 Mb/s Ethernet connection provide connectivity to a host PC. In addition, two digital programmable function interface PFI lines on the back of each device provide timing and synchronization capabilities (such as trigger and clock sharing) with other devices or external events.
What C Series modules are supported with NI Wi-Fi DAQ?
The following modules are supported by NI Wi-Fi DAQ carrier:
|
Module |
Signal |
Channels |
Rate |
Connectivity |
|
Thermocouple, 24 bit |
4 |
14 S/s |
Screw terminal |
|
|
Simultaneous sampling, 16 bit |
4 |
100 kS/s/ch |
Screw terminal or BNC |
|
|
Universal (11 modes) |
4 |
100 S/s/ch |
Spring terminal |
|
|
IEPE (accelerometer and microphone), 24 bit |
4 |
51.2 kS/s/ch |
BNC |
|
|
Bridge completion, 24 bit |
4 |
50 kS/s/ch |
RJ50 |
View details, specs, and pricing for modules .
What kind of power does Wi-Fi DAQ require?
Wi-Fi and Ethernet DAQ devices are DC powered and are compatible with 9-30 VDC power supplies. The included 12 VDC power supply may be used to power each device or you may wire any 9-30 VDC power to a device using the included screw terminal adapter. Maximum continuous current draw for a Wi-Fi device is typically between 250 mA and 350 mA, depending on which module is inserted into the carrier, and battery operation is possible. For example, a stack of eight AA 2400 mAh NiMH rechargeable batteries will typically last between 6.5 and 9.5 hours of continuous operation. Other battery combinations are possible with different capacities and voltage levels.
Do I need a router to perform measurements with Wi-Fi DAQ?
You do not need a wireless router to communicate with a Wi-Fi DAQ device, though most applications will use one. All that is required is a computer or laptop with 802.11b or 802.11g network connectivity. Wi-Fi DAQ devices support several network configurations from 802.11 ad hoc (peer-to-peer) networks to enterprise WPA2 networks.
Performance
The rate at which you can acquire data is limited by the type of C Series module you use in your WLS-9163 or ENET-9163 carrier. Currently, the fastest supported C Series module is the NI 9234, which can acquire up to 51.2 kS/s simultaneously on each of four channels. Both carriers support the full rate of this and other C Series modules. Note also that you may be limited in the amount (or rate) of data you can acquire depending on network traffic and the RF environment.
How many Wi-Fi DAQ devices can I use at once?
The number of devices you may use in a Wi-Fi data acquisition system is ultimately limited by the IEEE 802.11g standard and the bandwidth available in your wireless network/environment. There are three factors you should consider when determining how many Wi-Fi DAQ devices you can place in your system: acquisition rate, measurement type, and the RF environment. The faster you acquire data, the more TCP/IP packets your device must transfer back to a wireless access point or host PC. The same is true of a higher resolution measurement – some C Series modules provide 16 bits of resolution, while others provide up to 24 bits. Finally, the theoretical bandwidth of 802.11g is 54 Mb/s, though there are some practical limitations that keep this specification closer to 20 Mb/s. For example, you could stream data from more than 16 channels WLS-9234 24-bit measurements at the full 51.2 kS/s rate back to a single wireless access point.
How far can the signal travel?
The IEEE 802.11g standard has a typical range of approximately 30m, but this can vary significantly depending on your antenna type, wireless router, and physical obstructions. Line-of-sight transmissions are always best for long distance communication, and directional antennas can boost your signal dramatically.
What synchronization capabilities are available with Wi-Fi DAQ?
Two digital PFI lines on each Wi-Fi or Ethernet DAQ device provide start, pause, and reference triggers. They also offer the capability to import or export a sample clock for synchronizing your measurements with other DAQ devices or external events.
How long can an Ethernet cable be?
The maximum cable length for 100BASE-T Ethernet cables is typically between 90 and 100 meters.
Isolation electrically and physically separates sensor signals, which can be exposed to high-voltage transients and noise, from the measurement system’s low-voltage backplane. Isolation offers many benefits including:
- Protection for expensive equipment, the user, and data from transient voltages
- Improved noise immunity
- Ground loop removal
- Increased common-mode voltage rejection
Most C Series modules (including those supported by Wi-Fi and Ethernet DAQ) offer isolation as a means of improving the quality and safety of your measurements.
For more information on isolation, please refer to the NI Developer Zone Tutorial: Isolation Technologies for Reliable Industrial Measurements.
Security
What is 128-bit AES encryption?
The Advanced Encryption Standard (AES) was chosen by the IEEE 802.11i task group as the preferred encryption algorithm for securing data transmissions over Wi-Fi networks. AES uses a 128-bit cipher that is significantly more difficult to crack than the RC4 algorithm used by older Temporal Key Integrity Protocol (TKIP) and Wired Equivalent Privacy (WEP) encryption standards. In fact, the National Institute of Standards and Technology (NIST) chose AES as the encryption standard recommended for all U.S. government agencies. (FIPS publication 197 describes these requirements in detail.) Any wireless data acquisition application for the government or military will likely have to use AES to transmit data.
Network authentication is essentially client access control. Before a client (such as a Wi-Fi DAQ device) can communicate with a wireless access point it must authenticate with the network. There are two basic forms of authentication: server- and pre-shared key-based. Most enterprise networks have at least one authentication server, usually running Remote Authentication Dial-In User Service (RADIUS). WPA2 networks make use of the IEEE 802.1X port-based authentication standard, but there are other options as well. Wi-Fi DAQ devices support several extensible authentication protocol (EAP) methods, including LEAP, PEAP, EAP-TLS, and EAP-TTLS. You can also use a pre-shared key if you do not have an authentication server on your network.
Read more about Wi-Fi network security.
Software
How do I program Wi-Fi DAQ devices?
All Wi-Fi and Ethernet DAQ devices use the same NI-DAQmx measurement services and driver software as other National Instruments PCI, PXI, and USB data acquisition devices. NI-DAQmx measurement services software controls every aspect of your DAQ system from configuration to programming. With NI-DAQmx software, you can quickly configure and acquire measurements using the DAQ Assistant and automatically generate code to get your application started quickly. NI-DAQmx also features virtual channels that automatically scale raw data into engineering units. Because you can use the same driver API to program new Wi-Fi DAQ devices, incorporating wireless connectivity into your existing applications is easy.
What software is included with Wi-Fi DAQ devices?
In addition to NI-DAQmx driver software, all Wi-Fi and Ethernet DAQ devices include Measurement and Automation Explorer (MAX) configuration software and LabVIEW SignalExpress LE data-logging software. You can use MAX to quickly configure and test your Wi-Fi and Ethernet devices without developing any code. LabVIEW SignalExpress is interactive, measurement software for quickly acquiring, analyzing, and presenting data from hundreds of data acquisition devices and instruments, with no programming required. To learn more about LabVIEW SignalExpress LE, visit ni.com/labview/signalexpress/.
Which application development environments (ADEs) work with Wi-Fi DAQ?
Wi-Fi and Ethernet DAQ devices work with development environments compatible with NI-DAQmx, including:
- LabVIEW 7.x or later*
- LabVIEW SignalExpress LE or later
- NI LabWindows™/CVI 7.x or later
- NI Measurement Studio 7.x or later
- ANSI C/C++
- C#
- Visual Basic .NET
- Visual Basic 6.0
*Wi-Fi and Ethernet DAQ devices are not supported by LabVIEW Real-Time.
Test-drive LabVIEW software
Download the LabVIEW SignalExpress 30-day evaluation
Download Measurement Studio evaluation software
Services and Support
How do I get technical support for Wi-Fi DAQ devices?
NI offers extensive support options through ni.com/support. You can call, e-mail, or troubleshoot problems online with NI engineers. In addition, ni.com provides a wealth of resources for every customer – from users getting started with Wi-Fi DAQ to experts looking for tips from the designers. Online resources include:
- Downloadable drivers and updates for NI-DAQmx and other measurement products
- More than 3,000 KnowledgeBase entries
- Online product manuals (downloadable help files and PDFs)
- More than 3,000 example programs
- Tutorials and application notes
What warranty is provided with Wi-Fi DAQ devices?
All Wi-Fi and Ethernet DAQ devices have a one-year warranty that covers defects in workmanship and material from the date of shipment of the product. Extended warranty options are available that can help you to fix your maintenance costs over two or more years. Contact your NI sales representative for more information.
Additional Resources
Watch the Wi-Fi DAQ Guided Tour
View the Simplify Remote Monitoring with NI LabVIEW Webcast
The mark LabWindows is used under a license from Microsoft Corporation. Windows is a registered trademark of Microsoft Corporation in the United States and other countries.
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