Why not wireless?
Wireless technology,
particularly Wi-Fi (or 802.11b), is revolutionising many industries,
from automotive to medical, and the list continues to grow. One
industry that has yet to catch on to the trend is the industrial
automation market. So why has this industry so far largely failed
to adopt and implement this technology of the future?
Maybe the reason
is that there simply is no 'killer application' to enable widespread
deployment in industrial automation environments. It is widely thought
that Wi-Fi is expensive to implement, particularly in large industrial
automation environments such as a plant floor, not least because
of the limited range of 802.11b equipment. A cost-effective application
must first be developed to justify the expense and to date we simply
have not seen this happen. Once infrastructure is in place, experience
suggests that manufacturers will quickly find more ways to take
advantage of its functionality.
The large scale
of industrial settings presents problems for the cost-effective
installation of Wi-Fi connectivity. With a limited range, this technology
requires access points around every 15 to 30 metres (50 to 100 ft).
When devices need to roam more widely around the shop floor, the
cost of an installation that includes multiple access points can
easily make a project unattractive. There are other considerations
too. Industrial applications frequently operate in environments
that are noisy and performance is very often non-deterministic.
'Noise' in this context includes electromagnetic noise that has
the potential to interfere with unshielded applications.
Wi-Fi has been
a success where it can present solutions that are not achievable
in other ways. Hospitals, for example, have successfully integrated
Wi-Fi applications in operating theatres, emergency rooms and critical
care facilities. The justification is that wireless technology helps
to mobilise the expensive equipment necessary for quality control,
security and billing. By the end of 2001 some 1,000 or the US's
approximately 6,000 hospitals had deployed 802.11b networks. But
the differences between the healthcare and industrial applications
are important when considering the implementation of wireless connectivity.
Mobile medical devices that now require network connections are
very expensive pieces of equipment. Only limited numbers are available
in each hospital and they frequently have to be moved around the
hospital. As well as mobile connection, speed is a critical factor
in the medical arena: your crash team doesn't want to waste valuable
seconds sorting out a network connection. It is factors like this
that tip the balance towards Wi-Fi in a cost-benefit analysis.
In modern office
environments, which typically involve small areas compared with
large-scale industrial installations, wireless connectivity already
offers clear benefits. Wi-Fi is ideal for hot-desking in offices
where small laptop PCs can be connected to a company network in
a wide range of locations. This flexibility in working practices
can make the office much more productive as there is no longer any
need to plug and unplug network connections.
However we
should not dismiss wireless connectivity for industrial applications
out of hand, as it can it offer identifiable benefits. Where a networked
device needs to be free to move without the restriction of a network
cable, a wireless connection is the obvious answer. This is especially
true where a point-to-point connection is all that is required,
for example where the networked device does not need to roam widely
and have multiple points to connect to the network. The most likely
early uses of this wireless technology in an industrial environment
will be the installation of targeted point-to-point wireless connections
to a largely wired network.
At Digi we
have yet to see that 'killer application' in the industrial automation
environment, where business efficiency and operating advantage can
lead to return on investment that justifies the cost of a large-scale
wireless installation. Until this application appears, scrutiny
of Wi-Fi network proposals and cost-benefit analysis will continue
to lead to the use of more cost-effective alternatives on the shop
floor.
Digi International
k103@industrialnetworking.co.uk
|
