production line for up to a few days or even
weeks while it reconfigured gas piping and
retested for leaks and safety. This could also
involve a much larger rework of the entire
wiring system to conform to the latest safety
and fire codes when a legacy subsystem is
significantly modified.
Micrel chose not to implement this
solution due to the prohibitive cost of the
equipment, the installation and rework
labor, and most of all, the associated downtime and lost production, which altogether
approached $4,000 per gas cylinder (or more
than $400,000 to change 100 cylinders).
The Cypress Envirosystems
Solution
In 2007, Micrel learned of new wireless
gauge reader and wireless transducer reader
technologies from Cypress Envirosystems
that provide automated gas cylinder monitoring without the high cost and disruption
of installing traditional transducer-based
panels. The wireless gauge readers non-invasively “clip” onto the front of the legacy
manual gauge, and transmit the reading
wirelessly to a central server (Figure 2).
Similarly, the wireless transducer readers
simply attach to existing gas weigh scales
The Technology
Gauge Reader: The Wireless Gauge
Reader ( WGR) clamps onto the front of
a gauge and uses image sensing and
processing technology to digitize a dial
gauge reading, and then uses a 2.4Ghz
wireless mesh network to transmit data
with a range up to 1000m. A receiver/
hub collects the data for trend analysis,
notification, or statistical process control, and has battery life of two to three
years under typical sampling rates. Its
built-in database stores up to three
years of data in typical applications.
Its web server allows simple browser
access to data from any LAN connected
PC, and the device also allows two-way
without the need to remove or replace the
scale. Pre-set alarms of low gas levels may
be programmed to alert operator stations,
pagers, or cell phones. (See sidebar for an
explanation of this technology)
Micrel decided to implement the wireless solution because it incurred no process
downtime, required minimal installation
labor and training, and did not need retesting
for leaks and revalidation. The installed cost
of $1,250 per point (or $125,000 to change
over 100 cylinders) is just 35% of the cost of
traditional transducer panels ( Table 1).
Benefits
In the fall of 2007, Micrel decided to install
a mix of 100 wireless gauge readers and
wireless transducer readers to monitor its
most critical process gases, along with the
Cypress Envirosystems’ Blue Box Receiver,
which sends the data to Micrel’s existing
network and operator stations. Each data
point required between 10 and 30 minutes
to install, and did not involve breaking any
pressure seals anywhere in the gas system
or any process downtime. Additionally,
future integration of the data with existing
operator software is also possible via indus-
try standard OPC and/or BACNet protocols.
Within the first two months of operation, the
text messaging for sending notification
messages as well as on-demand data
requests from mobile handsets. The
receiver/hub has an optional OPC or
BACnet interface for integration with
existing automation systems.
Transducer Reader: The Wireless
Transducer Reader (WTR) connects to
existing transducers (e.g. weigh scales,
flow meters, pH meters, thermistors,
etc.) and uses the wireless mesh net-
work to transmit data to a receiver/hub,
much like the WGR. This unit can be
configured to read a variety of trans-
following benefits were identified:
Reduced the manpower devoted to ■
making gas rounds by one full-time
equivalent technician, who could then
be redeployed to other tasks.
Decreased gas consumption by approxi- ■
mately 10% annually, by using more gas
in each cylinder before change-out
Minimized unplanned downtime (e.g. ■
the system detected loss of gas pres-
sure/gas condensation due to unsea-
sonably cold weather—a situation
which can now be anticipated and
avoided in the future).
The combined operational savings are
estimated to be in the range of $215,000
per year (see Tables 1, 2 and 3 ). The resulting investment payback period is only
seven months (for the $125,000 initial
installed cost). G&I
For more information call
408-943-2800 or visit
www.cypressenvironsystems.com
PAUL NESDORE IS EDITOR OF GASES &
INSTRUMENTATION MAGAZINE. HE CAN BE REACHED
AT PNESDORE@GASESMAG.COM.
ducer inputs including 4-20mA, 0-5V,
0-10V, Type J and K thermocouples,
thermistors, and RS-232 and RS-485
serial communication. When paired
with non-invasive clamp-on current
meters and clamp-on ultrasonic flow
meters, the W TR can measure electrical
consumption and flow rate of chilled
water or steam and transmit the data
wirelessly. Installation typically takes
minutes, and may be uninstalled
and moved easily around a facility if
needed. It uses the same receiver/hub
as the WGR, which has an optional OPC
or BACnet interface for integration with
existing automation systems.
