Det-Tronics PIRECL Infrared Hydrocarbon Gas Detector PointWatch Eclipse - Manual (Page 3)

Important
Be sure to read and understand the entire
instruction manual before installing or operating
the gas detection system. This product is intended
to provide early warning of the presence of a
flammable or explosive gas mixture. Proper device
installation, operation, and maintenance is required
to ensure safe and effective operation. If this
equipment is used in a manner not specified in
this manual, safety protection may be impaired.
application
The Pointwatch Eclipse ® Model PIRECL is a diffusion-
based, point-type infrared gas detector that provides
continuous monitoring of combustible hydrocarbon gas
concentrations in the range of 0 to 100% LFL.
Three basic configurations are available:
• 4-20 mA output with HART communication protocol
and RS-485 MODBUS communications.
• 4-20 mA output with HART communication protocol
and RS-485 MODBUS communications, with two
alarm relays and one fault relay.
• Eagle Quantum Premier (EQP) compatible version
(no analog or relay outputs).
All units are powered from 24 volts DC, and are furnished
with an onboard "status indication" LED, an internal
magnetic calibration switch and an external calibration
line for use with the optional PIRTB remote calibration
termination box.
The Pointwatch Eclipse is ideal for use in harsh outdoor
environments and is certified for use in Class I, Division
1, and Zone 1 hazardous areas. It can be used as a
stand-alone detector, or as part of a larger facility
protection system using other Det-Tronics equipment
such as the FlexVu ® UD10 Universal Display Unit, the
U9500H Infiniti Transmitter, the R8471H Controller, or
the Eagle Quantum Premier Fire and Gas Detection/
Releasing System.
opERation ovERviEw
theory of operation
Flammable hydrocarbon gases diffuse through the
weather baffle assembly into the internal measurement
chamber, which is illuminated by an infrared (IR)
source. As the IR passes through the gas within the
chamber, certain IR wavelengths are absorbed by the
gas, while other IR wavelengths are not. The amount
of IR absorption is determined by the concentration of
the hydrocarbon gas. A pair of optical detectors and
associated electronics measure the absorption. The
change in intensity of the absorbed light (active signal)
is measured relative to the intensity of light at a non-
absorbed wavelength (reference signal). See Figure 1.
The microprocessor computes the gas concentration
and converts the value into a 4 to 20 milliampere current
output or digital process variable signal, which is then
communicated to external control and annunciation
systems.
inStrUCtionS
Infrared Hydrocarbon Gas Detector
PointWatch Eclipse ®
Model PIRECL
14.2 © Detector electronics Corporation 2013 Rev: 3/13 95-8526