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Fieldbus Evolution in Industrial
Automation
There has been attention around the
communications technology involved in Factory Automation.
The current buzz however involves a technology that
created a similar discussion in the Automation world
fifteen years earlier, "Ethernet". There hasn't been
so much written in regard to this network technology
since the great MAP (Manufacturing Automation Protocol)
debate of the mid 80's. Who can remember MAP and its
promise as the first interoperable real time network
for automation? Surely a token passing deterministic
master-less network architecture with predictable performance
for each node and the instant ability to recover the
token from a wacked out controller, was what many defined
as being required. Driven by some of the largest of
end user companies this technology promised to provide
real time deterministic interoperation among devices.
Automation vendors put some of their brightest talent
on the project with anxious enthusiasm. The sophistication
and complexity of achieving this end at the time however
had driven up costs to a prohibitive level that there
were only a limited number of installations by the end
of the eighties and its future was limited. I guess
this was sort of like the super sonic Concorde.
Entering into the nineties we saw the
ISP (Interoperable Systems Project) vs. FIP battle rage
on in which automation companies lined up on either
side for the ultimate show down. For several years the
groups continued to develop the architecture of the
ultimate Automation network. It was a hot summer in
1994 and after several years of development the moment
of truth had arrived. Was there going to be a Networking
winner? ARC called a convention of competing network
technologies in a hotel along the Charles River in Boston,
which had drawn a who's who in the networking world.
The big announcement was that the battle ended without
a shot being fired and there was no loser and in some
minds no winner either. Certainly disappointing for
those attending in the city that started the American
Revolution. Instead the two competing factions would
join together to form a new initiative now called Foundation
Fieldbus. This however was not the only network moving
on at the time. There were several others networks gaining
popularity being designed into the architectures of
the Automation companies who were unwilling to wait
several more years. The need for network connection
of devices was too compelling to wait. Devicenet / Controlnet,
Profibus, LonWorks, and Interbus S were in the early
stages of wide spread usage in their respected homelands.
Some of the FIP proponents as well especially companies
in France continued now under the new name WorldFIP.
This however did not spread throughout the world as
the new name suggested. Each Fieldbus offered a specific
advantage for certain industrial applications, but there
was to be no ultimate winner. During the meeting in
Boston there was no discussions at all with respect
to Ethernet which was clearly absent and presumed dead.
Ethernet was however being reborn in
the newly emerging world of the Internet. It seemed
that speed and bandwidth was not the exclusive concern
of the Automation industry. Websites were popping up
everywhere and traffic on the Internet was a multi-billion
dollar concern. Companies such as Cisco, 3Com and Lucent
all recognized the importance of the new network infrastructure.
As switch technology and speed improvements to 100 and
1000 Mbits were made available usage grew and prices
started to tumble downward. The use of Ethernet was
not totally absent from the Automation world, as it
was becoming a popular choice at the higher levels connecting
SCADA and Process Managements systems together. Commercial
Technologies and in particular Microsoft windows software
and to a limited extent PC based control was proving
that it certainly had a place on the Factory Floor.
The next introduction of the new Ethernet
for Automation occurred in the Board of Directors meetings
of Foundation Fieldbus. Foundation Fieldbus's Board
consisted of executives from 11 of the top Process and
PLC companies representing American, European and Japanese
companies. As a member of the Board it was extremely
interesting to participate in these sometimes heated
and closed discussions. During this time period the
concern of many of these companies was continuing to
work on yet another unique network architecture. Through
the persistence of Board members such as John Berra
President of Fisher Rosemount and Bruce Robinson (President
of Foxboro at that time) and with support of most, Ethernet
became an option for the high-speed element of FF program
(at that time referred to as H2, now known as HSE for
High Speed Ethernet). In March of 1998 in Houston, the
Board voted to adopt 100 Mbits Ethernet as the platform
to transport the protocol and function blocks of the
Foundation. This announcement prompted many if not all
the existing Fieldbus technologies to announce an initiative
to either transport or link to Ethernet TCP/IP.
With all these announcements there is
still a great deal of concern as to whether this technology
will be robust enough for Automation. I recall a similar
concern was heard back in the late eighties in regard
to Windows! There are certainly issues of connectors,
topology and EMI, which will have to be addressed. The
ability to solve these issues will allow expansion of
this technology further downward. The question is not
whether they will be solved but when. Several aspects
are currently being tested quietly in R&D centers
for incorporation into product releases when appropriately
addressing the application requirements of the specific
company. Seimens recently announced an entire product
family of Industrial Ethernet products focusing on many
of these issues. Rockwell will have most if not all
their products with an Ethernet connection by the end
of the year. Schneider Automation's "Transparent Factory"
iniative is completely aligned to the adoption of Ethernet
and Web Based technologies for the industrial environment.
GE-Fanuc was not a stranger to Ethernet and has offered
Ethernet for many years on many of it's products.
Assisting the push for low-end scaleable
solutions is the recent focus of the Commercial market
facilitated by Microsoft for a "Universal Plug and Play"
(UPnP) development targeted at the home and appliance
market. This market, which is orders of magnitude larger
than the industrial space, will further fuel technological
developments. Clients devices will not be just PCs but
everything from PDAs and Cellular Phones to set top
boxes. UPnP is not being ignored as a recent conference
in Redmond WA had several major Automation companies
present. Like Windows, OPC, and PC based control we
should expect benefits coming from this development
as well.
The recent announcement of GE coupling
with Cisco to focus on solving many of the networking
issues of the factory is yet another milestone not to
be minimized. Many believe that the major new frontier
for automation is not making individual machines run
faster but allowing Enterprises to run faster. As we
move in the next phase from Just in Time (JIT) manufacturing
to Make to Order (MTO) the ability to integrate departmental
communication including the plant floor is vital. Mass
customization and deployment of e-commerce B2B will
be the weapon for competitive positioning of corporations.
We at ICT are currently assisting many
of the Automation companies in interfacing current and
installed products by interfacing the installed Protocols
to Ethernet. A fact to remember is that Ethernet and
TCP/IP are not a Magic solution to solve all the issues
of networking. The various applications that make up
the complex space called Industrial Automation will
require the proper selection and installation of the
appropriate technology. This industry is conservative
with the livelihood of major corporations are resting
on the ability to produce product. It is the ability
to build and leverage these various networking technologies
that will provide significant improvements on the plant
floor.
Mark Fondl
President
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