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In
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COVER
STORIES
NEW
PRODUCT HIGHLIGHTS
PRODUCT
APPLICATIONS
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COVER
STORIES
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| Serial
to Wireless Basics—Part 2: Infrastructure Mode and Ad
Hoc Mode |
| This
series of articles about Serial to Wireless Basics is provided
by Moxa Technologies. Complete information about Moxa's
products is available on the Moxa Group website at www.moxa.com.
In these articles, we examine the basic concepts and applications
of wireless device servers. In this installment, we discuss
the meaning of "Infrastructure Mode" and "Ad-hoc Mode."
Many of you will be familiar with these terms from setting
up a wireless access point in your home or office. Deciding
which mode to use is governed by three main factors: (1)
The number of serial devices that you will connect to your
wireless LAN, (2) How widely the devices are dispersed,
and (3) Whether you need to access the devices from an outside
network.
Infrastructure
Mode
If your wireless LAN will include an unspecified number
of hosts dispersed over a wide area, or you need to access
your serial devices from an outside network, then configure
your wireless device servers for infrastructure mode. In
this case you will also need to install one or more wireless
access points. A typical situation in which infrastructure
mode is used is the factory floor work area shown in the
figure. In the traditional setup, each work area consists
of a computer connected directly to the serial devices in
that area. The computer could also be outfitted with an
Ethernet card and connected to the factory LAN and the Internet.
Traditional
Factory Floor Work Area
The wireless
alternative has the host computer communicating with the
serial devices over the network from a separate location,
such as an air conditioned control room. In this case, each
serial device is connected to a wireless device server,
and the wireless access points link the device servers to
the factory LAN.
Wireless
Alternative
Ad-hoc
Mode
Ad-hoc mode can be used to set up a private wireless LAN
that does not connect to an outside network. For example,
suppose you want to set up a simple control network that
includes a laptop PC with a wireless card installed, and
an industrial PC controlled by a small number of sensors
and actuators. It is likely that the sensors and actuators
are grouped into one RS-485 network, which can be connected
to a wireless device server. Setting up the control system
in this way eliminates the need to use wires to connect
the laptop to the control structure. In fact, the computer
could be located several meters away, or even in an adjacent
room.
Coming
soon...
In future issues of Moxa Connection, we
will discuss the following wireless device server topics:
- The
Economics of Wireless
- Security
Considerations
- Wireless
Rules of Thumb
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| MOXA
Sets Sail with DNV and Maritime Applications |
What
is DNV?
DNV is one of the world's
leading classification societies. DNV's Ship Classification
is a system for safeguarding life and property in the sea
environment. Obtaining DNV Type Approval entails verification
of a set of requirements during the design, construction,
and operation of ships and offshore units.
Moxa's Industrial
Ethernet Switches have already received DNV Certification,
and all tests meet or exceed the requirements of the guidelines
laid out in ICAS Unified Requirement E10 and the relevant
sections of IEC945 for equipment housed within a protected
environment. Test details can be viewed in the TL826 and
TL826A test report.
The combination of selected Location Classes
defines the different areas onboard in which the equipment
can be installed. Refer to the following Selection Guide
to see which Location Classes are most suitable for your
application.
Selection
Guide of Location Classes
Moxa applied for the following applications:
| Temperature |
D |
| Humidity |
B |
| Vibration |
A |
| EMC |
B |
| Enclosure |
Required protection according to the rules to be
provided upon installatino onboard |
Special
Notice
Though Moxa received Class D for the Temperature test, we
would like to suggest that you select the wide temperature
"-T" models when you install the product in a
harsh environment. In general, the standard models can meet
your requirements, since they passed the class B temperature
test of DNV.
Product Groups that passed DNV Type Approval
Moxa's DNV type approved products include the following
models. These products are the best choice for your marine
and offshore applications.
| Product |
Type
Designation/
Specification |
| EDS-305-X1-X2-X3-X4 |
Unmanaged Ethernet Switch |
| EDS-308-X1-X2-X3-X4 |
Unmanaged
Ethernet Switch |
| EDS-405-X1-X2-X3-X4 |
Unmanaged
Redundant
Ethernet Switch |
| EDS-508-X1-X2-X3-X4 |
Managed
Ethernet Switch (Single/Multi) |
| IMC-101-X1-X2-X3-X4 |
Industrial
Media Converter,
Ethernet to Fiber |
| X1 (Fiber Mode) |
M
or S or MM or MS or SS |
| X2
(Fiber Category) |
SC
or ST |
X3
(Fiber Transmissible
Distance) |
40
or 80 |
| X4
(Temperature) |
0-9,
A-Z or blank |
| X2
and X3 should not appear when X1 is blank. |
|
Applications
If you are working in a maritime type of environment, such
as offshore drilling, coastal windmills, or shipbuilding,
and are looking for Ethernet equipment that can withstand
the rigors of such environments, then check out Moxa's industrial
Ethernet switches and media converters.
 |
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| Gas & Oil |
Windmills |
Shipbuilding |
Back
to top |
| See
Moxa's Newest Products at Computex 2005 |
| Moxa
will display its full line of products at Computex Taipei
2005, the second largest trade show in the world for the
IT industry. You can find us in Hall 1,
Booths A822/824/826, in the Taipei World
Trade Center complex.
Moxa's new NPort
Wireless Device Servers and Gigabit
Ethernet Switches will be displayed at this year's show.
Other product lines that will be exhibited include NPort
Series Serial Device Servers, NE
Series Embedded Network Enablers, Universal
Communicators, Multiport
Serial Boards, Terminal
Servers, and Industrial
Ethernet Switches. A large-sized product application
poster titled "Connecting Devices for a Convenient
Life" is sure to attract a lot of attention during
this 5-day trade show. We will also set up a static demo
area with detailed explanations on the exhibition wall,
and new product training sessions and informative seminars
will be conducted on the second floor in conference room
4.
If you haven't seen our full line of products, here is your
chance. You can find us in
Hall
1
Booths
A822/824/826
We
look forward to seeing you there.
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|
| In
next month's issue: Get
the Scoop on Universal Communicator |
Tune
in next month when we give you in-depth technical information
about using Moxa's Universal
Communicator series, one of the biggest sellers among
the new Moxa products introduced this year. But what is a
Universal Communicator anyway? The latest in multi-language
translation? Something that will come in handy when we finally
"make contact" with beings from another world? Not
exactly. The UC series consists of miniature front-end computers
designed for use with industrial device networking applications.
Universal Communicators are C programmable, and feature multiple
transmission and data storage options, making them suitable
for a wide range of industrial device networking applications.
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NEW
PRODUCT HIGHLIGHTS
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| Moxa's
New AirWorks AWK-1100 Gives Industrial Applications an Easy
Jump to Wireless |
|  Moxa
Networking is releasing an industrial IEEE 802.11g
wireless product that can be used as an AP, bridge,
or AP client. The new product is called AirWorks AWK-1100,
and is designed for use with Ethernet switches and
other Ethernet-ready devices to provide ready access
to a wireless LAN. Attractive features include advanced
WPA (Wi-Fi Protected Access) security capability,
operating temperature range from 0 to 60°C, and
redundant power inputs. If current plans go as expected,
AWK-1100
will be available from Moxa Networking's distributors
in the middle of June.
Connecting industrial Ethernet devices to a wireless
LAN is not just another fad. Wireless networking is
a good choice for many networking requirements due
to the flexibility that comes from being able to set
up a network anywhere and anytime. Wireless networks
can be set up quickly in areas that are not yet wired,
or are too hard to wire. In addition, the high performance
that wireless networks provide, and the cost savings
that comes from using fewer cables are also a plus.
One of the biggest concerns raised by potential users
is safety. Since data is transmitted through the air
by radio waves, how can users guarantee the confidentiality
of their information? Moxa answers this problem by
providing Wi-Fi Protected Access (WPA) security specifications
to overcome weaknesses in Wired Equivalent Privacy
(WEP).
AWK-1100
is designed for industrial applications that require
connecting an Ethernet-ready device to a wireless
LAN. AWK-1100
can authenticate and authorize wireless users by IEEE
802.1X and RADIUS (Remote Authentication User Dial-In
Service), and communicate with a back-end RADIUS server
to see if a wireless user is allowed to access the
wireless network. The DIN-Rail mounting feature, wide
operating temperature range, and IP30 case with LED
indicators make AWK-1100
a convenient plug-and-play and reliable solution for
industrial wireless applications.
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APPLICATIONS
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| Automatic
Monitoring and Control of Traffic with UC-7420 |
Introduction
Techniques for controlling traffic have been in use
ever since the automobile became the standard mode of
transportation in the early 1900's. Perhaps the most
familiar example is the stoplight, which in its most
basic form uses a simple timer to determine when the
light will change. The timed traffic light poses a problem
for low-traffic intersections, since cars may need to
wait at a red light for an extended period of time,
even when there are no cars driving by on the cross
street. This problem is usually solved by embedding
a simple inductor-type automobile sensor just under
the surface of the pavement. Controlling high-traffic
intersections is more complicated, and is best handled
using algorithms that depend on the number of cars coming
from all directions at any given time, or using human
operators to switch the lights based on a visual observation
of the number of cars waiting at the intersection.
 In
addition to traffic lights, other sensors and traffic
related devices commonly used include cameras, roadside
LED displays, street lights, parking lot entrances,
and even parking meters. What has been missing until
recently is an easy and economical way to monitor and
control the devices located in a given area, such as
at an intersection or a self service parking lot. Moxa's
UC-7420,
a miniature front-end computer with eight RS-232/422/485
serial ports, dual Ethernet ports, PCMCIA card that
supports 802.11b/g wireless LAN capability, and an industrial
strength no fan, no hard drive design, is ideal for
these kinds of applications. UC-7420's
built-in Linux operating system makes it easy to install
software, and the Flash expansion slot lets users add
additional memory space as needed.
Traffic
Control at Busy Intersections
At busy intersections,
IP cameras can be used to allow human operators to
gage the number of cars waiting at the intersection.
UC-7420
transmits the images over the Internet from the intersection
to a remote monitoring center. Signals that control
the status of each traffic light can also be transmitted
via UC-7420
to the monitoring center. For this type of application,
the human operators use their traffic control experience
to determine the best time to change the light from
red to green to alleviate snarled traffic conditions.
Placing this combination of IP camera and UC at busy
intersections around a large city gives traffic engineers
a city-wide traffic control system. Roadside LED displays
can also be used to issue traffic warnings to motorists
to help them avoid the most congested areas.
Controlling
Traffic in an Automated Parking Lot
We've
all had the experience of entering a large parking lot,
only to drive aimlessly around the lot for several minutes
before locating an available space. To eliminate this
problem, a combination of sensors and LED displays can
be used to create an effective traffic control system
that directs motorists from the entrance to the nearest
empty parking space.
One option is to use sensors that detect automatically
which parking spaces are occupied and which spaces are
empty. The sensors can be connected to a UC-7420
via a local RS-485 network. The UC can be programmed
to monitor the sensors continuously, and when a car
leaves a space, this information is relayed to a central
computer over an Ethernet LAN, or 802.11 wireless LAN.
UC can also be used to connect the LED displays to a
central computer. The central computer monitors the
information from all of the sensors in the parking lot,
and when a car enters the parking lot, it uses the LED
displays to direct the driver to the nearest empty space.
Benefits
of Using Moxa's Universal Communicator
- No
fan, no hard drive design for longer MTBF
- CompactFlash
slot for adding Gigabytes of storage space
- Dual-LAN
ports for setting up super-redundant systems
- Programmability
gives system integrators infinite possibilities
- Wireless
ready
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|
| Safeguarding
the World's Historic Sites with Wireless Device Servers |
| Historic
buildings and sites around the world have been major tourist
attractions for thousands of years. The ancient Romans,
for example, loved taking trips to Egypt to marvel at the
pyramids and other Egyptian monuments erected thousands
of years earlier. In this day and age, interesting sites
are scattered around the world in places as diverse as Mexico,
the United States, Thailand, China, and countries in Europe.
A major problem faced by those entrusted with the care and
upkeep of historic sites is security. For most sites, it's
impossible to hire a large enough security force to watch
all parts of a site 24 hours a day. However, the networked
21st Century world we live in offers cost-effective high-tech
solutions for keeping a watchful eye on all parts of even
the largest sites. The newest solution of this type makes
use of the wireless device server to connect surveillance
cameras to a central control room. Wireless is chosen to
minimize the amount of wiring or re-wiring required at the
site. Keeping the devices out of sight is also a plus, since
doing so greatly reduces the chance of malicious tampering.
Depending on the size of the site, one or two operators
can easily watch all areas of the site from the control
room, and then send a security guard to investigate when
trouble arises.
Moxa offers two palm-sized wireless device servers that
can be used for this kind of application. The 1-port NPort
W2150 or 2-port NPort
W2250 can be used to extend wireless networking capability
to cameras, card readers, and other data collection devices,
making either product suitable for improving security at
the world's historic sites.
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PROMOTIONS
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MOXA
Catalog on CD:
Products / Applications / Tutorials |
|
The CD-ROM version
of Moxa's 2005 Device Networking Catalog is ready for distribution.
This catalog on a CD gives current and prospective Moxa
customers a convenient source of information. The catalog
contains detailed information about Moxa's products, as
well as informative tutorials that discuss technical issues.
Up to date product applications are also included to give
customers a head start on setting up and using Moxa's various
products.
Customers of all types can find what they're looking for
in the new catalog, and the CD-ROM version makes it more
convenient to locate information. The new catalog has information
about several new products that did not appear in last year's
catalog, including a new line of wireless serial device
servers and a Gigabit Ethernet switch. The new wireless
serial device servers bring traditional serial devices into
the WLAN era.
The Moxa catalog includes detailed specifications and ordering
information for all products. An easy way to obtain a copy
of the CD version of the new Moxa catalog is to use Moxa's
online request form at http://web4.moxa.com/free/request_catalog.asp.
You may also contact Moxa directly by e-mail or phone.
Back
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|
| UPDATE—Wireless
Device Server Daily Winner Contest |
| Moxa's
Wireless Device Server Daily Winner Contest, which runs
from May 1 to June 30 of this year, is off to a great start.
We have already received a large number of applications,
and have been choosing winners on a daily basis. The rules
are simple—one new winner is selected each work day
(Monday, Tuesday, Wednesday, Thursday, and Friday), with
winners chosen based on the novelty of their product applications.
Click
here to view the winner's list!
Contest
Information |
Name:
Date: |
Wireless
Device Server Daily Winner
Runs from May 1 to June 30 of this year
We
are giving away 1 NPort 2150 each work day! |
|
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DID
YOU KNOW? |
|
--
by Tim Stemple
Did
you know that the first traffic light
was implemented in London in 1868 to control horse and
buggy, wagon, and pedestrian traffic? The light was
powered by gas instead of electricity, and was modeled
after the railroad signals in common use at that time.
After cars became commonplace at the beginning of the
20th Century, engineers realized the need to coordinate
signals for lights at successive intersections. For
example, a manually operated system of six interconnected
traffic lights was installed in Salt Lake City in 1917.
The ideal modern traffic control system for a large
metropolis is a city-wide system that helps eliminate
traffic jams and reduce the waiting times of drivers
going to and from work. In this day and age of fast
computers, fiber-optic networks, digital surveillance
cameras, and advanced pattern recognition algorithms,
it may seem that anything is possible. Take Chicago,
Illinois, for example. In the pre-Internet, pre-PC era
of the early 1970's, Chicago already had a sophisticated
traffic monitoring system that fed data from sensors
buried beneath the freeways to a mainframe computer
for processing (click
here for more information). The system was designed
to display expected travel times to major landmarks
on electronic signs located on the side of the highway.
Some of Moxa's products can play an essential role in
traffic control systems. A prime example is UC-7420,
which is featured in the application story Automatic
Monitoring and Control of Traffic with UC-7420.
In this story, we outline two applications that use
Moxa's Universal Communicator. The first application
involves controlling traffic flow at a busy intersection.
The second story is about setting up a control system
for large parking lots that directs motorists to the
nearest empty parking space.
Additional
References
About
Traffic Lights
Traffic
Control in NYC
The
Gas Museum
Traffic
Light System
Chicago's
Freeways
ITS
Decision website
This common interest column is published each month
in Moxa Connection. Click
here to contact Tim by e-mail.
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