products are extending the capabilities of the National
Instruments wireless sensor network (WSN) platform. A new 9792 programmable
gateway provides a platform for embedded wireless monitoring and data logging
that doesn't require a connection to a back end system. The WSN-3226
voltage/resistance temperature detector (RTD) combination node extends the
measurement capabilities to include support for resistance-based measurements
such as RTDs and potentiometers.
idea behind releasing the NI 9792 gateway is targeting more embedded wireless
monitoring applications," says Nick Butler, wireless sensor network product manager
for National Instruments. "What we mean by embedded is headless applications
where we don't need a host controller in the system. Similar to systems created
with CompactRIO and other LabVIEW real-time targets, the gateway doesn't need
to be tethered to a back end system."
gateway can be deployed to monitor a bridge, tunnel, mine shaft, winery or rain
forest without the need for an Ethernet connection back to a Windows PC, PXI
system or any other controller," Butler says. "Users can have data logging
applications, analysis, trending and alarming all running locally on the
gateway is programmable using the LabVIEW Real-Time Module for stand-alone
operation and features a high-performance 533 MHz processor and 2 GByte of
onboard storage for embedded data-logging. It features integrated web (HTTP)
and file (FTP) servers which makes it possible for remote access to measurement
data from thin client devices such as smartphones and mobile computers. An
RS232 serial port and dual Ethernet ports provide flexible connectivity to
other devices such as enterprise-level networks or wired I/O systems.
important feature is the new built-in web server. With any type of monitoring
application, there is always the question of data visualization. If the gateway
is in a remote location, how will the user get data if it isn't tethered to
anything? The value of the local I/O is the ability to add a radio modem to the
system next to the gateway. Typically cell modems and other devices will
communicate via Ethernet, TCP/IP, Modbus or serial, all open standards that the
user can program in the LabVIEW real-time application running on the gateway.
Without investing in a separate controller, the system can provide monitoring,
processing and visualization of the data. Users can also combine the gateway
with a CompactRIO controller to easily implement a wired and wireless
measurement system, because the APIs are very similar.
applications are typically split between those that require high speed, high
throughput and maybe FPGA timing synchronization and processing on the wired
side with slower speed, more SCADA-type systems that NI is addressing through
the WSN platform.
a trend moving toward wireless in all facets except for high speed control,"
says Butler. "A high percentage of customers intend to adopt wireless
technology in the future and the majority is planning to adopt wireless for
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says the real controversy today is whether wireless is suited for control. With
the latency of over-the-air communications and the potential for nodes or
distributed wireless devices to lose their wireless connection or experience
interference, the jury is still very much out on wireless for control for
mission-critical applications. "But in measurement applications, we have
already crossed that chasm and we're seeing heavy adoption of wireless
measurement technology today," says Butler.
with the new gateways, three measurement nodes include a +
input node and a 24-bit thermocouple node. The WSN-3226 measurement node adds
resistance-based measurements to the WSN platform and features four analog
input channels that can be configured on a per-channel basis for ±10V
measurements or resistive measurements.
WSN-3226 features two bidirectional digital channels that can be configured on
a per-channel basis for input, sinking output or sourcing output. Additionally,
the measurement node can be powered by four AA batteries, with an operational
lifetime of up to three years, or externally powered with a 5 to 30V supply,
which offers improved efficiency for energy harvesting applications.
says the main application they are targeting is adding RTDs to the WSN
platform. Typically customers that require high accuracy temperature
measurements select an RTD rather than a thermocouple for their temperature
monitoring applications. With the release of this node, WSN devices can
natively interact with RTDs for temperature measurements and combine those with
analog input measurements on the same node.
the nodes are available in a programmable version, and allow users to take
advantage of LabVIEW graphical programming to wirelessly deploy analysis and
control programs that run autonomously on the WSN measurement nodes," says
Butler. "The deployed applications can control the digital lines for ON/OFF
control, save data samples locally to Flash memory, and perform local analysis,
averaging or data reduction."
water treatment facility, for example, a customer could take pH and dissolved
oxygen measurements in the tanks once an hour, store the 24 samples to Flash
memory, then average them or send all 24 data points at midnight each day. This
flexibility provides users with the ability to customize the operation of
measurement nodes to optimize power consumption and performance.
key differentiator of wireless sensor network devices is that the user can program
how the node operates, how often it samples, what it does with the data, how
often it transmits that data and how often it responds to digital value changes
on the DIO lines." says Butler. "You can even respond to network status
changes. For example, if your gateway happens to lose power, the node's
deployed application will continue to run and you can start saving data locally
to the node. Upon reconnection to the gateway, the node can automatically
transmit all of the sampled data so that none is lost even if the network goes