3600I
Page: 5
The IR3 technique utilizes few infrared sensors, each sensitive to its own wavelength
range. The first sensor is sensitive to wavelengths within the emission peak of hot CO
2
.
The other two sensors are sensitive to wavelengths above and below this peak. The
fourth IR sensor is sensitive to a different band within the emission peak of hot CO
2
. In
the event of fire, the signal measured in the first sensor is significantly higher than those
measured in the second two sensors. In order to issue a fire alarm, the detector
requires that this occurs, as well as other conditions (for example, radiation is flickering
in frequencies typical of flames). The signal of this sensor is compared to those of the
other three. This increases sensitivity for some types of flames. (For example, gas
flames).If exposed to non-fire radiation sources, the specific conditions required does
not occur, and the detector does not react.
1.4.2 HEATED
OPTICS
The 3600 Flame Detectors use heated optics. The heater increases the temperature of
the optical surface by 5-8°F (~3-5°C) above the ambient temperature to improve
performance in icing, condensation and snow conditions.
The heated optics can be set to one of the following:
•
Not
operated
•
On
continuously
•
Automatic, per temperature change (default): you can define the start temperature
below which the window is heated. (The default is 41°F (5°C). This temperature can
be defined between 32°F (0°C) to 122°F (50°C). The heating stops when the
temperature is 27°F (15°C) above the start temperature.
For more information, see
Configuring your Detector
on page 27.
1.4.3 HART
PROTOCOL
The 3600 Flame Detectors use the HART Protocol.
HART Communication is a bi-directional industrial field communication protocol used to
communicate between intelligent field instruments and host systems. HART is the
global standard for smart process instrumentation and the majority of smart field
devices installed in plants worldwide are HART-enabled. HART is available in wiring
options 2 and 3, see Table 1.
HART technology is easy to use and very reliable.
Through the HART connection, you are able to perform:
•
Detector
set-up
•
Detector
troubleshooting
•
Detector health and status
For more details, refer to the
HART Manual TM 777030
.
1.4.4 RS-485
MODBUS
For more advanced communications, the 3600 detector has an RS 485 Modbus-
compatible output that provides data communication from a network (up to 247
detectors) to a host computer or universal controller for central monitoring. This feature
allows for reduced installation costs, easy maintenance and local or remote diagnostic
tools.