Honeywell Searchline Excel Open-Path Technical Handbook page 59

MAN0530 Issue 09 October 03
2104M0506
• Electrical interference due to proximity of radio or radar antennae
• Flooding or frequent wave deluge
• Direct heat e.g. from adjacent flare stack, intense sunlight
The maximum certified operating temperature for Excel is +65 ° C
Note:
• Contamination build up e.g. oil mist, sea spray, drilling mud, exhaust fumes
In addition, since the Transmitter and Receiver protrude from the duct wall, adequate precautions
should be taken to protect personnel.
To ensure optimum performance, do not cover the Excel with insulation, and allow free air
movement around the unit.
Beam Path
The path of the infrared beam is unlikely to be affected by the same obstructions that can affect
the Open-Path Excel. However, consideration should be given to avoid:
• Steam vents
• Splash and spray
Orientation
The Cross-Duct Excel should be mounted on a vertical, flat surface such that the optical axis is
horizontal. Although the Excel units will tolerate a certain amount of vibration and misalignment,
ensure the surface is rigid and stable. Fit additional supports prior to installation if necessary.
The retro reflector should be mounted directly opposite, and perpendicular to the optical axis of
the Transmitter/Receiver assembly. If the duct walls are not exactly vertical or parallel, the
position of the cut out for the retro panel must be adjusted to compensate. Depending on the
duct width, the Cross-Duct Excel will tolerate up to three degrees of angular misalignment of
the mounting plate, or 15 degrees tilt of the retro reflector.
It is not advisable to install the Cross-Duct Excel on the top or bottom of the duct. In this
orientation the retro panel or the Transmitter/Receiver unit will be susceptible to the build up of
contamination.
4.3.2 Electrical connections
The electrical installation of Cross-Duct Excel requires the same care and attention as the Open-
Path version. See section 3.3.1 for general precautions. The electrical connections are similar to
the Open-Path version of Searchline Excel, but with the Transmitter and Receiver supply being
common and connected into the same junction box on the mounting plate.
4.3.3 Power Supply
The Cross-Duct Searchline Excel is designed to be operated from a nominal 24V DC supply. At
the Excel units, the supply voltage must be within the range 18 to 32V. The field cabling conductors
should have sufficient cross sectional area to ensure that the minimum supply voltage applied
to the gas detector is 18V at a current of 720mA.
This corresponds to a maximum round loop impedance of 8.3 ohms for a nominal 24V system
supply.
4. CROSS-DUCT EXCEL
59
Searchline Excel