M2M Device Networking:
Enabling New
Possibilities for Preventive Maintenance (cont.)
By Marty Huff
(Got to beginning page of Device
Networking Technology Article)
The Gateway: Translates and Passes The Data To The Network
The gateway is responsible for extracting raw data from the intelligent
device and preparing it for the network. Gateways are typically hardware
but can also be a combination of hardware and software.
Gateways use a protocol such as Modbus or a proprietary device driver
to interact with the intelligent device, and translate the data into a
format that another device, software application or human can understand.
The gateway can also act as, or interact with, a Web server to serve files
to Web browsers, allowing multiple simultaneous connections to Web pages.
Gateways may also have other enhanced functionality such as the ability to
convert media types (e.g., serial to Ethernet). For example, a gateway
such as Advantech's WebLink can communicate with intelligent devices via
serial, Ethernet, and/or USB connections. With a PCMCIA cellular modem
acting as the network connection, the WebLink can also collect and send
data via cellular service.
for M2M networks. Cellular data transfer overcomes most limitations of
distance and location.
The Network: The Connectivity
That Serves Data To The Remote Client
In an M2M application, the network is like any other network: it is the
connection that allows data to pass from one place to another. The four
most popular network connectivity choices in an M2M system are:
- Wired Ethernet
- Wireless (802.11x, Bluetooth, 802.15...)
Cellular
- POTS (Plain Ol' Telephone Service)
Wired Ethernet is
often used when the intelligent device is part of an existing LAN or can
be connected to an existing LAN. The device can then be accessed by
another device, software application, or human at the same location, or
via the Internet using the existing Internet connection on the LAN. Wired
Ethernet is completely secure as long as any Internet connections on the
LAN are carefully protected by a firewall. A local area network also has,
by far, the highest data transfer rates.
Nokia
and Sierra Wireless are two major players in the forefront of
wireless and cellular hardware.
Nokia
and Sierra Wireless are two major players in the forefront of
wireless and cellular hardware.
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Wireless is a
good choice when wires are not feasible and devices are within short range
of each other. Wireless technology is cost-effective, secure, and stable,
but very limited by distance. With a wireless network, you can create an
always-on connection between the intelligent device and an existing LAN or
other wireless-enabled device, with the data transfer rate much higher
than a cellular or wired modem. Security is more of an issue than with
wired connections. Rather than a standard firewall, wireless devices
require different security measures, for example, encryption or IPSec.
Currently, the two most popular wireless technologies are Wi-Fi (802.11x)
and Bluetooth. Zigbee (802.15) is a new wireless protocol designed
specifically for direct machine-to-machine communications.
Cellular
data modules and cards are becoming increasingly popular Third party
applications or custom software programs are used to facilitate
machine-to-machine communications, provide an operator interface, and
provide Web browser access and Internet presence. One such program is
Advantech Studio (A-Studio) provides all of the necessary tools to
communicate with the device, Web-enable the application, and deliver data
securely to all levels of the enterprise. A-Studio provides a user
friendly 'drag and drop' programming environment. Microsoft's .NET
platform also provides the tools necessary to program a custom M2M
application for both embedded and non-embedded platforms.
Cellular tends to
be more expensive than other connection types and is not the best choice
for applications that require high bandwidth and real-time, always-on
access to the device. In many situations, however, cellular is the only
feasible choice. Additional security measures such as client-initiated
VPNs (virtual private networks) are often used with cellular Internet
connections to ensure the integrity of the device.
POTS remains
popular because of its low cost and security. POTS can be used for both
direct dial connections and Internet connections. POTS is a good choice
for applications that do not require heavy data transfer as it continues
to be a slower method of delivery. DSL (Digital Subscriber Line) running
over POTS is quite a bit faster and can be configured for an always-on,
firewall-secured connection at a relatively low price.
Other network
possibilities include Satellite Internet Service, GPS Technologies,
dedicated long-range RF, Infrared and more. These are seldom used due to a
combination of factors including price, distance or stability.
It may seem confusing when choosing a network type but it is usually
quite simple. The network of choice is, in most cases, dictated by two
factors: location and existing resources including the availability of
phone or data lines. The figure above shows the decision process based on
these factors.
M2M Components
There are basically four components in an M2M system: 1) the
intelligent device (machine or appliance) where the data originates, 2)
the gateway that extracts and translates data, 3) the network which serves
the data and 4) the remote client which ultimately receives the data. M2M
software applications are optional but can facilitate communications,
enable Web access and provide the user interface.
Please See the following pages to continue with this Preventive
Maintenance Technology Article...
The Intelligent Device:
Where The Data Originates
The Gateway: Translates and Passes The Data To The Network
The Network: The Connectivity That Serves Data To The Remote
Client
The Remote
Client: The Destination Of The Information
Marty Huff - MSI
Tec, Inc.
About the Author:
Marty Huff is an IT professional with MSI Tec and can be reached
directly at 720-875-9835 or by email at mailto:martyh@msitec.com.
MSI Tec is a provider of intelligent machine control components
and systems, and the value adding engineering resources for the
successful identification and implementation of their use.
Marty is responsible for M2M systems design,
programming and installation and is available for dedicated
training programs and seminars on the subject of M2M.
Don Fitchett, Business
Industrial Network, contributor to this article.
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