无线传感器网络 (WSN)测量节点
Ø借助4节AA电池供电, 可持续运行3年
ØNI LabVIEW集成和NI-WSN软件可轻松实现网络配置和数据提取
Ø选择针对可编程和不可编程节点
Ø可编程节点包含使用NI LabVIEW WSN Module Pioneer对节点进行编程的许可证
Ø工业评级:-40 °C到70 °C的操作温度范围, 50 g抗震, 5 g防振动
Ø直接的传感器连接; 网格路由 (mesh routing)功能
Ø了解可编程节点的优势
Ø查看NI WSN产品和配置指南
Ø购买NI WSN起步包
Ø了解WSN拓扑和网状网络
NI WLS-9163 and C Series Hardware
Each NI Wi-Fi DAQ device is a combination of an NI WLS-9163 wireless carrier and an NI C Series signal conditioning module. The WLS-9163 provides both IEEE 802.11b/g and Ethernet connectivity back to a host PC.
Figure 2. Each Wi-Fi NI CompactDAQ device combines an NI cDAQ-9191 chassis and an NI C Series module to provide wireless sensor measurements.
C Series modules offer direct sensor connections, NIST-traceable calibration, and built-in signal conditioning for a variety of measurements, including temperature, high-voltage digital I/O, strain, acceleration, current, and voltage. In addition to the NI cDAQ-9191 wireless chassis, you can use C Series modules interchangeably for measurement and control applications with different chassis, including 4- and 8-slot NI CompactDAQ chassis and CompactRIO, as well as the NI USB-9171 single module chassis and NI cDAQ-9181 Ethernet chassis.
Secure Wireless Data Acquisition
Wi-Fi NI CompactDAQ devices implement the highest commercially available wireless network security standard, IEEE 802.11i (commonly known as WPA2 Enterprise), including IEEE 802.1X network authentication and 128-bit AES data encryption. Authentication ensures that only authorized devices have network access, and encryption prevents data packets from being intercepted. Accepted worldwide, IEEE 802.11i security standards build on more than 10 years of wireless innovation in the IT sector. By using standard security protocols, NI Wi-Fi DAQ devices make it easy to add wireless measurements to IT networks safely.
Streaming Wireless Measurements with NI-DAQmx Software
After more than 20 years of helping engineers and scientists achieve high-quality PC-based data acquisition, NI-DAQmx driver software continues to be the heart of the National Instruments data acquisition platform. Recognizing the diversity of measurement applications, NI approaches data acquisition independent of specific PC bus technologies. You can use the same NI-DAQmx API for communicating across PCI, PCI Express, PXI, PXI Express, USB, Ethernet, and Wi-Fi. This means you can use an application developed for a USB data acquisition device (even a high-speed application) with a wireless data acquisition device without making any changes to the software.
Figure 3. NI-DAQmx driver software abstracts data acquisition bus technology from the user and provides a consistent API across multiple programming languages.
NI Wi-Fi DAQ devices can stream continuous 24-bit waveform data at more than 50 kS/s from multiple measurement channels. Managing this amount of data over a wireless network is a nontrivial task, but NI-DAQmx abstracts the complexity associated with buffered transfers over TCP/IP from the user. With device-side intelligence, message-based communication, and an advanced streaming engine, NI-DAQmx and NI Wi-Fi DAQ provide all the benefits of wireless technology for test and measurement applications without sacrificing the performance or reliability of a wired solution.
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2. NI Wireless Sensor Network Devices
A wireless sensor network is a wireless network consisting of spatially distributed autonomous devices that use sensors to monitor physical or environmental conditions. These autonomous devices, or nodes, combine with routers and a gateway to create a typical WSN system. The distributed measurement nodes communicate wirelessly to a central gateway, which provides a connection to the wired world where you can collect, process, analyze, and present your measurement data. To extend distance and reliability in a wireless sensor network, you can use routers to gain an additional communication link between end nodes and the gateway.
Figure 4. Common Wireless Sensor Network Architecture
National Instruments Wireless Sensor Networks offer reliable, low-power measurement nodes that operate for up to three years on 4 AA batteries and can be deployed for long-term, remote operation. The NI WSN protocol based on IEEE 802.15.4 technology provides a low-power communication standard that offers mesh routing capabilities to extend network distance and reliability.
Learn more about NI Wireless Sensor Networks
Read this Instrumentation Newsletter article on wireless sensor networks
NI WSN Hardware
For most WSN applications, you can create a basic network architecture in which the distributed measurement nodes acquire data from the environment around them and transmit these measurements to a gateway. NI WSNs provide the flexibility to connect your Ethernet gateway to a Windows or LabVIEW Real-Time host controller.
Figure 5. NI WSN Gateway and measurement nodes form a distributed wireless sensor network.
The NI WSN Ethernet gateway coordinates communication between distributed measurement nodes and the host controller in your NI wireless sensor network. The gateway has a 2.4 GHz, IEEE 802.15.4 radio to collect measurement data from the sensor network and a 10/100 Mbit/s Ethernet port to provide flexible connectivity to a Windows or LabVIEW Real-Time host controller. The gateway can accommodate up to 8 end nodes, but can be extended to communicate with up to 36 nodes when router nodes are implemented in your network topology.
The high-accuracy NI WSN measurement nodes provide four analog input channels and four digital input/output channels for easy sensor connectivity, while four AA alkaline cells deliver up to a three-year lifetime. You can configure each digital channel as input, sinking output, or sourcing output. The WSN-3202 also offers an up to 12 V, 20 mA sensor power output line that draws from the battery or external power supply to drive external sensors.
NI-WSN Software
By using LabVIEW software to design your wireless sensor network system, you benefit from the rapid development of graphical programming for your entire solution. With LabVIEW, you can use the same graphical programming approach to create the node intelligence; develop desktop or embedded real-time applications that perform data logging, processing, and alarming; and take advantage of Web services that provide access to your application from any Web-enabled device.
Figure 6. Use the LabVIEW graphical programming platform to enhance and customize your wireless sensor network.
Simply drag and drop I/O variables from the LabVIEW Project to a LabVIEW block diagram for data extraction, analysis, and presentation. You can also use I/O variables to monitor node attributes such as link quality and battery voltage and determine if a node is configured as an end device or mesh router. You can create a simple data extraction program or integrate your WSN LabVIEW code into a complete wired and wireless measurement and analysis program.
LabVIEW WSN Software
The LabVIEW Wireless Sensor Network Module extends the LabVIEW graphical programming environment to create and deploy embedded applications to programmable NI WSN measurement nodes. Use LabVIEW WSN Pioneer to extend battery life by optimizing node behavior, perform custom analysis, and embed decision making on programmable NI WSN measurement nodes.
Figure 7. The NI LabVIEW WSN Module deploys embedded LabVIEW applications to NI WSN measurement nodes.
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3. Additional Resources
View the NI WSN homepage
View the wireless NI CompactDAQ homepage
网关
在WSN系统中，网关相当于网络协调员，负责节点授权和消息缓存。网关从分布的节点收集测量数据并将其发送到企业网络，在企业网络中可使用各种NI软件收集、处理、分析和显示测量数据。 在WSN系统中，可使用多个网关，每个网关都对应于一个独立的软件可选的无线通道。
可编程网关
NI 9792既是一款LabVIEW Real-Time控制器也是WSN网关，是嵌入式无线数据记录的理想之选。 通过双以太网端口，可基于LabVIEW Real-Time应用程序和各种设备进行通信。例如，企业级网络或蜂窝式调制解调器。 这款高性能控制器提供533 MHz处理器、2 GB板载内存、2.4 GHz IEEE 802.15.4无线，以便与最多36个分布式NI WSN测量节点（网状网络配置）进行通信。 使用集成的Web服务器可远程访问WSN系统数据。
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C系列网关
NI 9795为NI WSN和CompactRIO平台的紧密集成提供了方案。 C系列网关可插入CompactRIO系统的任何插槽，从而为现有的测量和控制系统提供无线I/O。网关可与36个分布式的NI WSN测量节点（网状网络配置）通信，为CompactRIO系统上的LabVIEW Real-Time应用程序提供测量数据。
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Ethernet网关
与可独立运行LabVIEW Real-Time 应用程序的NI 9792不同，NI WSN-9791以太网网关是一个中间设备，必须连接至一个主机系统。 网关拥有2.4 GHz、IEEE 802.15.4的无线收发设备能够收集源自传感器网络的测量数据，1个10/100 Mbit/s以太网端口可灵活连接Windows或LabVIEW Real-Time主控制器。
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测量节点
NI WSN测量节点可直接与传感器连接，通信可靠，是工业级通信设备。 该设备由电池供电，4节5号电池可供设备使用3年。在室外使用时，可在设备外加装NI防护外壳。 使用LabVIEW WSN模块可对节点进行编程，灵活定制节点的程序，进行本地分析和控制等操作。 关于节点编程和LabVIEW WSN功能的详细信息，请参考软件部分。
NI WSN-3202模拟输入测量节点
NI WSN-3202测量节点提供4条输入范围可选的±10 V模拟输入通道，4条双向数字通道。可对这些通道编程，实现事件检测或本地检测。18针螺栓端子连接器可直接与传感器连接；设备提供的12 V、20 mA电源输出可以直接为需要外部电源的传感器供电。
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NI WSN-3212热电偶输入节点
NI WSN-3212测量节点提供4条24位热电偶输入通道，4条双向数字通道。可对这些通道编程，实现事件检测或本地检测。节点支持J, K, R, S, T, N, B, E热电偶类型，也可使用各个热电偶输入通道作为±73mV模拟输入通道。
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NI WSN-3226 电压/RTD组合节点
可编程的NI WSN-3226测量节点将基于电阻的测量（如RTD或电位计等）添加至NI WSN平台。 WSN-3226有4条模拟输入通道，可按通道配置为±10 V的电压测量或电阻测量，在一台设备上实现温度和电压测量。 设备还有两条双向数字通道，通道可接收标准工业范围的电压。通过编程可实现事件检测或本地检测。 WSN-3226可抑制50/60 Hz的噪声并具有12 V、50 mA传感器电源输出，可驱动需要外界电源的传感器。
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NI WSN-3214 应力/电桥节点
NI WSN-3214应力/电桥节点将波形采集功能纳入了WSN产品，是结构健康监测类无线应用的理想之选。 该节点有4条模拟通道，支持1/4桥、半桥和全桥。节点还有两条数字I/O通道，用于事件检测和可编程的控制。 可使用LabVIEW WSN模块，处理和分析节点上的应力数据，判断是否有错误情况发生。 还可选择是否传输整个波形或传输分析后的数据。传输分析后的数据可减少无线传输的数据量，延长WSN测量节点的电池使用寿命。
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NI WSN-3230 RS-232串口节点
WSN-3230有一个RS232端口，用于和串口传感器或设备通信。该节点仅支持编程模式，可作为一个自主串行接口。 使用LabVIEW WSN模块，可将查询和解析算法直接嵌入WSN节点，从而创建一个多种串口设备都可使用的远程可编程接口。 还节点还有两条数字I/O通道，可通过编程实现事件检测或控制。
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NI WSN-3231 RS-485串口节点
WSN-3231有一个RS485端口，用于和串口传感器设备或控制板通信。该编程节点仅支持编程模式，可作为一个自主串行接口。 使用LabVIEW WSN模块，可将查询和解析算法直接嵌入WSN节点，从而创建一个多种串口设备都可使用的远程可编程接口。 还节点还有两条数字I/O通道，可通过编程实现事件检测或控制。
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