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Planning for Automation System Upgrades:
Total Replacement versus Phased Migration
By Robb Dussault and Grant Van Hemert -----------------------------------------------------------------------
Choosing the best method for migration
involves weighing both the short and longterm costs and benefits. Three main paths
of migration often are pursued: complete,
phased and partial.
In the water and wastewater industries,
years, thereby minimizing tax burden and
Complete Migration
most facilities are designed with a 20-25
often negating the need for loans, bonds
Traditionally, a complete or total migrayear life cycle and the installed equipment
or grants. Some municipalities even have
tion was considered the only option for an
is expected to last the duration. Yet, in the
performed migration through the use of
automation system upgrade. A total migrafield of integrated circuitry the obsolesunused maintenance funds.
tion consists of removing all existing equipcence rate is less then five years. This has an
How Do You Choose?
ment and making a complete, single-step
impact on the computers, SCADA hardware
Having a choice in migration methods
switchover to a new processor, software,
and programmable automation controller
allows municipalities to evaluate the scope
I/O and wiring. This one-time installation
(PAC) hardware found in water and wasteand cost of their migration project and betis the highest initial investment and is the
water facilities.
ter manage it to fit into their maintenance
greatest disruption to plant operations. In
Most automation vendors have done an
schedule, downtime and budget — but how
addition, total migrations require the most
excellent job of recognizing this challenge
do you choose? Plant operators and maintetime to complete because installing a new
and continue to manufacture parts long
nance personnel need to answer the followsystem can involve many unknown factors.
after a product line has become obsolete.
ing questions when deciding the migration
Municipalities should choose this option
However, an aging automation system’s
path to choose:
if they are making large-scale changes to
obsolete components translate to indefinite
• How much of an initial investment do
their facility and massive function changes
costs, unpredictable maintenance requireyou want to make now and in the near
to a process. In this case, it’s more benefiments and increased potential for downfuture?
cial for a municipality to choose a comtime.
• How long can you afford to have the
plete migration and to make the function
When municipalities think about retrofitsystem down?
changes on the new platform rather than
ting their existing automation system and
• Do you want to switch platforms or stay the old one. Choosing a complete migrasoftware, often their thoughts turn to the
with the existing automation systems
tion for this scenario offers the municipality
immense burden, risk and cost associated
provider?
a one-time installation and
with an upgrade. Upgrading
a comprehensive solution.
automation systems shouldn’t
A northern Chicago water treatment plant chose to partially migrate its automation system by re- Also, complete migration
be considered from merely
is the option for a mua short-term perspective,
placing its SY/MAX® processors with Modicon® QuantumTM programmable automation controllers
nicipality looking to switch
though. When properly ana(PAC), while still retaining the SY/MAX I/O. The facility can change out the I/O at its leisure.
platforms.
lyzed, the increased reliability,
enhanced processing power
Phased Migration
and other long-term benefits
Phased migration is often
often outweigh the time and
the best option for municicost invested today.
palities looking to upgrade
More importantly, migratheir entire system while
tion doesn’t have to be a
also reducing their initial
burden or require extensive
investment and downtime.
resources. Today, automation
Phased migration takes
services companies offer a
a multiple-step approach
variety of ways to upgrade. A
to upgrading and can be
total migration used to be the
spread out over a number
only option, but now, simple
of months or years. In adand phased migration methods
dition, a municipality may
allow municipalities to upgrade
be able to finance a phased
one or two components, or
migration with each year’s
their entire system, over a
maintenance budget.
longer period of time. This
In a water/wastewater
allows a municipality to budget
facility, phased migrathe migration across multiple
tion can be accomplished
Reprinted with revisions to format, from the October 2007 edition of WATERWORLD
Copyright 2007 by PennWell Corporation
COVER
FEATURE
Migrating your automation system has become easier than ever as municipalities can choose between a complete,
phased or partial migration. Having a choice in migration methods allows municipalities to evaluate the scope and
cost of their migration project and better manage it to fit their maintenance schedule, downtime and budget.
However, the open ended commitment
means that the municipality should periodically coordinate with the automation vendor
to ensure that parts not yet migrated will
be available. Availability of spare parts can
shorten, or lengthen, the time frame to complete the migration. Partial migration is an
attractive option for municipalities that also
continue to use their original automation
systems provider.
Municipalities that can benefit from this
migration method are those that need only
minimal upgrading, or have systems in
isolated zones of automation. For example,
a facility that has a reliable I/O but wants to
add functionality and capacity to its processor and system would be an ideal candidate
for a partial migration. In the future, the
facility could opt to upgrade the I/O and
software program if necessary.
Reaping the
Benefits of Migration
by changing one train at a time. This can
provide dual control systems during a
changeover, it minimizes plant disruption
and ensures reliability. All the steps of the
phased migration method can be completed
relatively seamlessly and quickly, and reduce
the risk of taking the entire facility out of
commission. In addition, if there are scope
changes or last-minute adjustments to the
functionality of the system, phased migration allows the facility to use the existing
train until final changes are made to the new
system.
Today, municipalities are finding that
phased migration makes sense because critical process trains can’t be down for longer
than a few hours. In addition, a phased
approach would be most beneficial if a facility’s process is based on an old programming
architecture that doesn’t communicate with
any of the other equipment, and the operator always wants to be able to maintain and
diagnose it using the maintenance personnel
available. In this case, the municipality can
easily upgrade each piece of the system step
by step and revert back to the old system if
there are last-minute adjustments.
Phased migration puts the organization’s
destiny in its own hands. Municipalities
have more control of the migration process
because it’s simpler for them to monitor the
progress of the conversion. Plus, scheduling
migration means downtime can be planned
for when it is most convenient and least
likely to negatively impact treatment.
Not only does a phased migration involve
more flexibility and a lower initial investment, but one of the biggest advantages
to this option is the migration products
and experience of the automation systems
provider. Often, the provider’s conversion
expertise can reduce the amount of time a
process is offline, and minimize the need for
replacement control panels.
Facilities taking advantage of the benefits
of phased migration must use their original
automation systems provider. If a municipality wants to change providers, a complete
migration will be necessary because automation systems providers cannot upgrade
components from another provider.
Partial Migration
Partial migration is a single-step upgrade
of only one or two components or systems.
Unlike a phased migration, a partial migration does not have a defined timetable for
continued migration. This open-ended
timetable means that a municipality can
resume upgrading at any point in the future
when time and budget allows. A partial
migration has the smallest initial investment,
and like a phased migration path, facilities
can take advantage of their provider’s conversion products and services, and can revert
back to their old system if need be.
Having a choice in migration methods
allows a municipality to identify the type
of upgrade best-suited to its unique situation. Municipal governments are much
more likely to allow a treatment facility to
upgrade its automation systems if the facility
can tailor a method that meets its individual
needs while reducing cost, burden and risk,
and making the project more manageable
from a budgetary standpoint. WW
About the Authors
Robb Dussault is the manager for automation and control services
for Schneider Electric. He has more than 14 years of experience
in automation, and previously was an applications engineer and
worked in hardware development and product management.
Dussault can be reach at [email protected].
com. Grant Van Hemert is an automation and control applications
engineer for the Schneider Electric Water Wastewater Competency
Center. Van Hemert has over 11 years of water and wastewater
experience. Previously he was a design and implementation
engineer where he designed and commissioned automation and
instrumentation systems dealing with aeration, screening, and
clarification. Van Hemert can be reached at Grant.VanHemert@
us.schneider-electric.com.
www.SquareD-Water.com
9510NA0701