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MAN0530 Issue 15 - 07/17
2104M0506
Searchline Excel is a hydrocarbon gas detection system that is available in two versions:
•
Searchline Excel Open-Path Gas Detector
•
Searchline Excel Cross-Duct Gas Detector
For information regarding the Cross-Duct Excel please refer to the Searchline Excel Cross-Duct
Technical Handbook, part number 2104M0520.
Searchline Excel Open-Path Gas Detector (OPGD) consists of a Transmitter unit that sends an
infrared beam to a Receiver unit up to 200 metres away, and can be located where a flammable
hydrocarbon gas cloud is likely to occur.
The detector operates on the principle of infrared (IR) absorption. Gases absorb light at specific
wavelengths depending on their molecular composition. Hydrocarbon gases absorb in the
infrared region of the spectrum. If a cloud of hydrocarbon gas is present, part of the infrared
light is absorbed by the gas, causing a reduction in the signal received that is proportional to
the amount of gas in the beam.
The Searchline Excel Transmitter unit produces the infrared light, and the Receiver unit features
optical detectors and signal processing electronics. Each unit is housed in a robust stainless
steel housing. The Receiver produces a 4 - 20mA analogue output equivalent to 0 - 5 LEL.m
(Lower Explosive Limit metres) of gas.
NOTE:
THE INFRARED BEAM IS INVISIBLE AND EYE SAFE
Searchline Excel is designed for use in the most demanding environments/applications and
provides a sensitive, fast and reliable response. The sophisticated open-path technology
provides immunity to sunlight and minimises the effects of environmental factors such as rain,
fog, ice, snow and condensation.
The Transmitter and Receiver units incorporate heated optics designed to minimise the build
up of humidity, condensation, snow or ice on the glass windows, that could obscure the optics
in extreme conditions.
The system is microprocessor controlled with integral self-diagnostics and fault finding
facilities.
Local communication between an operator/technician and the gas detector system is made
via an associated Handheld Interrogator that uses the Receiver's inbuilt RS485 serial link.
The interrogator provides the user with a menu-style interface to select and invoke commands
for commissioning and configuring the system, and for viewing the system state and
measurements.
The interrogator is connected to the Receiver via one of Honeywell Analytics' DX100 (M) series
types of Termination Unit, or via other types of junction box (including the Honeywell OELD
smart junction box) using the optional SHC Protection Device. The DX100(M) Termination Units
feature an active digital interface that allows a remotely located control centre to monitor the
gas detector's signal output and perform basic commands using the Modbus Remote Terminal
Unit (RTU) protocol over an RS485 link.
1. INTRODUCTION
6
Searchline Excel
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