INFRARED FLAMMABLE GAS DETECTOR HIGH RELIABILITY LOW MAINTENANCE

The 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 "no-quibble" warranty.

UNRIVALLED STABILITY
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.

AUTOMATIC AND REMOTE FUNCTIONAL TESTING 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.

SIMPLE 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.

ULTIMATE 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.