FLAMMABLE GAS DETECTOR HIGH RELIABILITY LOW
highly stable optical performance of CIRRUS provides a
factory calibration that will last for 5 years
...CIRRUS never requires zero or span gas calibration.
The reliability of CIRRUS has been assessed
independently using MIL Handbook 217F/2/12/91 to give
a MTBF of 8.6 years. This figure includes the infrared
source ! The optical system will function up to 90%
obscuration. The system will automatically indicate
when obscuration reaches a preset level. ...there is
no need to clean CIRRUS until it tells you to! This
reliability allows for a five year
Flammable gas detectors have to be totally reliable...
This is why CROWCON developed the optical unit in
CIRRUS to have two sources delivering two beams, each
at different wavelengths and each measured by separate
detectors. One beam, not sensitive to hydrocarbons,
continuously checks the integrity of the optics and
provides an on-going zero measurement for the
hydrocarbon detecting beam at a different wavelength.
Thus any drift in the IR source is compensated for.
CIRRUS uses a proprietary `fuzzy optic' design
developed by CROWCON. With `fuzzy optics', IR beams
are measured over a larger area than normal meaning
the optics in CIRRUS are particularly tolerant to
shock and vibration. All this leads to only 2% drift
over five years.
CIRRUS can be fitted with an automatic drop-in filter
which mimics gas and checks the function of the unit.
Plus a precalibrated filter or test cell which can be
inserted into the beam. ...CIRRUS does not need manual
or local functional testing. Where local regulations
do require testing, CIRRUS has a flow adaptor for use
with compressed gas and remote gassing points or
interfaces can also be fitted to aid testing of units
mounted in inaccessible areas.
INSTALLATION AND UPGRADE The unique 'smart' docking
station of CIRRUS simplifies both installation and
system changes. It contains connections for field
wiring and an optional PROM which is used to
characterise the detector at that location. At
installation, the docking station is sitted and wired
up with the detector head being fitted later during
commissioning. Future configuration changes are made
by simply changing the PROM at the docking station.
...CIRRUS offers easy field reconfiguration.
FLEXIBILITY CIRRUS offers complete connection
flexibility with both 4-20 mA and RS485 outputs.
Addressable detectors can be looped together via the
Modbus serial link providing remote control and
interrogation capability. CIRRUS also offers a
pellistor mimic for updating or extending existing
pellistor-based systems. This interface converts the
4-20 mA signal of CIRRUS into a pellistor-compatible
form which means existing cabling to the control panel
can be retained.