SCADA Radio Networks for Water and Wastewater
Built for the People Who Run Them
Office Phone: 954 961 2642
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Now more than ever technology options for creating a radio connected SCADA system are vast. The intention of this site is to provide resources for those tasked with designing, maintaining or operating mission critical SCADA systems. FCC licensed, unlicensed and cellular technology will be discussed along with pros and cons of each. SCADA radio networks often require initial design effort. This effort, if spent well can afford the owner a robust, highly reliable communications network with optimized value.
Water
and Wastewater SCADA Radio Networks; Fundamentals, Best Practices and
Choices
from the Perspective of a System Owner & Operator
1.
Start
with First Principles
a.
Water
and waste water operations are a mission
critical use case
b.
High
technical standards required for mission
critical data transport integrity and reliability
c.
The
best part is no part, said another way less
points of failure is best.
d.
In
a world of limited resources, solutions
must also be affordable.
e.
Clearly
define the current and future SCADA radio
network service area
f.
Clearly
define the data rate required (hint, often slower
is better)
g.
Select
a radio modem technology that has a long manufacturer & service life.
2.
What
does "mission
critical" mean in the data communications world
a.
If
a communications outage can result in public harm,
then you are in a mission critical need case.
Example is public safety police & fire dispatch
also many utility
operations such as water production well fields, water distribution or
lift
station systems.
i.
Utility
examples; Lift station overflow or operation
failure that results in a boil water order.
b.
Data
communications downtime is measured in minutes
per year, vs hours or days. Five
nines
99.999% availability = 315 seconds per year of down time, ~ 5 minutes
per year.
c.
Spare
parts must be available and maintained
d.
The
SCADA radio network is operational before during
and after a hurricane or storm event.
3.
How
do we incorporate best practices and high standards in our SCADA radio
networks?
a.
Understand,
CELLULAR NETWORKS ARE NOT MISSION
CRITICAL GRADE
i.
Cell
sites are vulnerable to power outages, wind
damage, cyber-attacks, Cell modems must be replaced every 3-5 years due
to
evolution in cell tech (think 3G, 4G, LTE, 5G), forced dependence on
the cellular
carrier to restore communications after an outage event.
b.
SCADA
radio networks are designed with expertise and
tools, then tested before the design is qualified as acceptable. Often referred to as a
“In-Field Radio Study”
i.
Radio
network designs include a "20 dB RF fade
margin” for each radio path, data reliability comes from meeting this
minimum
standard.
ii.
In-field
radio study is the last step in the design
where the radio network is set up temporarily and the RF signal levels
in each radio
path are measured and confirmed that the computer modeled RF design
meets real
world performance.
c.
Allocate
resources wisely, tall antenna towers vs smart
towers. Dollars are
easy to spend and
hard to come by. Large
towers require
large foundations and have large construction efforts, steel and
concrete
costs. Our goal is
to build the mission critical SCADA radio
network with the lowest antenna towers possible.
d.
When
defining the service area consider future needs
/ expansion.
e.
Select
the best SCADA radio modem technology for the
system requirements.
i.
150
MHz, 220 MHz, 460 MHz, 800 MHz, 900 MHz
Licensed, 900 MHz, 2.4GHz, 3.6 GHz, 4.9 GHz, 5.1 GHz, 5.8 GHz
Unlicensed, Mesh,
Microwave, Etc.
f.
Build
all SCADA antenna systems to survive 150 – 200
MPH wind storms, yes this can be done with a robust design.
4.
SCADA
Radio Networks Maintenance
a.
Antennas
only last 10 years, plan to replace them
all at year 9
b.
Perform
preventative maintenance on all master and
high importance RTU sites at least once per year.
c.
Not
all antennas are created equal they; vary in
construction quality, cost, gain and wind survival ratings.
d.
Surge
protectors, know their failure modes and how
to test them.
e.
Radios
can degrade over time, have a plan to replace
the ones that are under performing, especially the master or sub master
radios.
f.
Know
if radio modem obsolescence will become an issue
and have a plan.
g.
Create a master RTU radio station log
/ spreadsheet;
record every station’s RF strength, signal to noise level, data quality
metrics
annually and draw attention to any changes over the life of the network.
SCADA communications networks can achieve minimal down time
measured in minutes
per year vs. weeks after a severe weather event, power failures, cable
cuts, etc. SCADA radio networks are
completely controlled by the owner and their maintenance organization,
Vs. telco, cable, or cellular communications carriers.
Private
secure and autonomous data radio networks are not vulnerable to
cyber-attack / terrorism or hackers, Article from Wired Magazine on Cyber War.
Proper
planning and control of your spare parts program can make a return to
service as simple as replacing a broken part. Tornados,
hurricanes, fires, and power outages often cause cellular networks
outages, as site backup power is usually a small number of minutes,
cell sites rely on wired telco infrastructure to create the cellular
network backhaul connections that
are required for operation. Commercial power availability is
required for both wireless and wired connectivity as their (telco
& cellular) backup power access is typically minimal.
The industry standard for designing SCADA radio links (both FCC
licensed and unlicensed) is 20 dB of RF fade margin.
This defines the additional radio
signal
that is designed into each radio link to insure
reliability. What the 20 dB fade margin really means is that
there is 100 times more signal than the minimum amount of RF carrier
signal
needed to reliably operate the radio link and transport your mission
critical SCADA data on
it. Decibels are logarithmic numbers and a little goes a long
way to
provide data reliability.
There are countless SCADA radio networks throughout the
United States and abroad monitoring and controlling municipal water,
waste water, flood water, oil & gas production, power grids,
automatic meter
reading, and much more. These mission critical radio technology based
communications systems have ranges from yards to hundreds of
miles. Selecting the right technology, defining the projects
requirements, and creating a robust SCADA communications network is
what I do as an RF consultant. Having the personal
understanding and experience of the pros and
cons
of each technology can empower the project engineer, owner or operator
to make
the best business decisions for a system that will have a 10-20 year
service
lifetime and are often mission critical or high importance
factor operation SCADA systems.
Please browse this site, if you have any questions or a specific
project you would like to discuss, please feel free to call
on me, Mark Lavallee. I truly enjoy sharing my 30 years of
specialized experience and knowledge. My company is often
called upon
assist design build consultants, controls system integrators, and the
end
users directly. We are highly specialized with tools and
talent for auditing existing SCADA systems, selecting the best SCADA
radio technology
for
new systems, and providing qualified radio network designs / in-field
radios studies.
954-961-2642
or
email:
mark.lavallee@advantage-com.com
Over 33 years of experience, "When Failure is Not an Option"
