Environmental Science & Engineering - www.esemag.com - May 2004
Comments? send them to the editor.
Ultrasonic system improves efficiency
Located in Victoria, British
Colombia, the Capital Regional
District (CRD), includes 13
municipalities serving a population
of 342,000. The District’s
Environmental Services division is
responsible for the remediation of surface
waters, sewer maintenance and
wastewater treatment. The group manages
facilities at about 100 sites.
In 2001, CRD began a major
upgrade of the level measurement
equipment in the pumping stations and
trunk sewers. The old, existing analog
instruments had limited capabilities.
They lost accuracy in converting to
digital format and communicating
with the remote telemetry unit (RTU).
They used a proprietary format. This
configuration did not offer accurate,
repeatable data, and had limited scope.
Peter Breen, Electronics Technologist,
and his team evaluated proposals
from five suppliers. They looked first
for accuracy, functionality and wealth
of data. A distributor for Siemens
Milltronics, Thomas Mackay and Son
Ltd., recommended the EnviroRanger®
ultrasonic system with an accuracy of
+/-0.25%, no analog drift or A/D conversion
losses, and the best price-performance
ratio.
EnviroRanger offers monitoring
and control in one package, and has a
built-in RTU. Five relays control any
combination of pumps, gates and
alarms. It provides accurate level monitoring,
and monitors flow in flumes,
weirs and open channels. It integrates
easily with SCADA, DCS or PLC to
provide remote monitoring of all
parameters - level, pump control functions,
pump status, and more, using
Modbus protocol. It offers report by
exception and data logging for trend
analysis. It also features patented
Sonic Intelligence® signal processing
for superior reliability.
CRD chose the DC-powered version
to allow for simplified battery
back-up. EnviroRanger can operate on
back-up battery power as low as 12
volts. At 10 pumping stations and 19
trunk sewers, CRD installed a total of
40 units. Level data from the flumes is
collected continuously on a real-time
basis over radio modems by the
SCADA system to calculate flow.
EnviroRanger offers dual point monitoring
and, at the flume sites, CRD
added the expandable I/O cards to
monitor more discrete inputs such as
floats, rain gauges, door switches, or
lighting on or off, without the expense
of an additional RTU.
Many of the sensors are mounted in
narrow wet wells or flumes. Echomax®
transducers solved this problem
because their narrow beam angle
avoids interference from walls or
obstructions. For ranges up to eight
metres (26 ft), they used Echomax
XRS-5 and, for deeper wells, they
chose XPS-15 transducers with a
range of 15 metres (50 ft).
Because EnviroRanger has a builtin
RTU, CRD avoided the cost of 19
external RTUs, saving more than
$100,000.
Efficiency has been improved with
more complete, accurate, reliable data
now available through direct digital
access, with no analog outputs or analog-
to-digital conversions required.
Contact: www.siemens-milltronics.com.
See our home page on how to order your subscription. We regret we can
only accept orders from Canada and the United States.