What A Mesh!
During open-circuit events, this wireless system contacts key personnel, telling them what PPE to bring for repairs.
IT'S an imperfect world. All tends toward
entropy, dissolution, and decay; things
break, fall out, shrivel. In industrial
environments, belts snap, parts erode, fuses
blow. The latter happens more often than
you might think.
Cooper Bussmann Inc., an Ellisville,
Mo.-based manufacturer of power fuses
and circuit protection products, conducted
a comprehensive study of facilities in the
automotive, petrochemical, and metals
manufacturing industries and found opencircuit
events caused by short circuits and
overloads happened an average of 382
times annually per facility. Each event
resulted in an average 41 minutes of
unscheduled downtime costing hundreds
of thousands of dollars per incident—
sometimes millions of dollars. In the auto
industry, for example, where cars come off
the assembly line at a rate of roughly one
per minute, even 15 minutes of downtime
caused by one blown fuse or tripped circuit
breaker can cost in the neighborhood of
$330,000, the study showed.
“When a circuit opens, for whatever
reason, what happens is maintenance has
to go out and troubleshoot it,” says Joe
Fox, Cooper Bussmann director of systems
and services. “They have to figure
out why the equipment is not operating
and where the problem is. Once they
determine they have a fuse open, they
have to figure out why it’s open and what
kind of fuse it is, and then they have to go
get the replacement part and put it in
there. It can be very time consuming.”
What if the circuits themselves could
automatically alert those maintenance
workers? What if the circuits were able to
call, e-mail, or fax the workers, telling them
the exact location of the event, the exact
replacement part to bring, and the appropriate
level of PPE to have with them for
the work? These were the seemingly
far-fetched musings that led to the introduction
earlier this year of the Cooper
InVision™ Downtime Reduction System,
a monitoring and communication system
that uses wireless technology to provide
precisely these kinds of notification.
Intelligent Circuitry
At the heart of the InVision system is a
“self-healing” wireless mesh network of
routers, or data transmitters, that engineers
install at a customer’s facility after
doing an initial site assessment that
includes tests of the facility’s physical and
radio environments to determine how
many routers are
needed and where
they should be
placed for optimal
transmission. The
“brains” of the
system, meanwhile, are
the battery-powered
intelligent fuse and intelligent
circuit monitors (IFMs and ICMs)
that oversee circuits and initiate the transmissions,
sending alerts to the routers
when they detect problems.
Unlike traditional point-to-point wired
and wireless systems, which can lose data
when anything interrupts the primary path
between a transmitter and receiver, the
InVision routers “talk” to each other in different
directions. So if a connection is lost
or blocked between any two routers—
when, say, a moving metal platform or
forklift gets in the way—another router
picks up the message. Such route redundancy
is designed into the system so an
alternate path will guarantee communication
between the IFMs/ICMs and a device
called the “gateway,” a component installed
at the customer’s facility that encrypts data
received from the routers before sending it
on to dedicated servers at Cooper Bussmann’s
access-restricted data center via a
secure Internet connection.
The servers that receive the transmission,
collectively called the “command
center,” display the status of monitored circuits
and allow for easy configuration of
alert escalation and trending reports. The
command center also sends the automatic
voice, e-mail, or fax alerts using information
provided by a customer’s facility manager.
The necessary level of PPE and
replacement part information programmed
into the system is determined by a fuse’s or
circuit’s location within a site’s electrical
system and the potential hazards surrounding
that particular room or panel.
The facility manager also designates who
receives the alerts, ensuring that only qualified
personnel get the messages.
Sensor Sensibility
Cooper Bussmann software engineer
Michael Pearce describes the InVision
system as “self contained” but adds that it
works with a customer’s existing network
and Internet connection. “All the devices in
the system have their own microprocessors
in them, and they provide all the functionality
to communicate
up to our
servers,” he says. “But this is not a standard-
based wireless protocol. It’s not
802.11, it’s not ZigBee, and it’s not Bluetooth.
It’s nothing you’ve ever heard of. It’s
tailored specifically to our application,
which allows us to have a large number of
devices that can conserve battery power.”
The number of devices needed to compose
the mesh at a facility contributes to
the system’s price, which Fox says can vary
significantly, depending on the site’s size
and environment and how many critical
loads are monitored. The system has a
capacity of 200 routers per gateway, but
multiple gateways can be installed. The
batteries powering the IFMs and ICMs last
up to 4.5 years. For more information and
an online downtime cost calculator, visit
www.cooperbussmann.com.
This article originally appeared in the July 2007 issue of Occupational Health & Safety.