Emerson Rosemount CCO 5500, Reference Manual

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5. The maximum cable length allowed between the power supply and the source is 33
ft. (10 m).
6. The maximum cable length between the power supply and the receiver is 82 ft. (25
m).
2.4.1 Points to consider
Path length
1. Too long [> 26 ft (8 m)]: low energy available.
2. Too short [< 1.6 ft (0.5 m): optical problems
Flue gas temperature
1. Too low (< dewpoint): potential water droplets.
2. Too high [> 572 °F (> 300 °C)]: reduced sensitivity.
Ambient temperature
1. Too low [< -4 °F (< -20 °C)]: condensation on lenses.
2. Too high [> 158 °F (> 70 °C)]: potential instrument problems.
Measurement range
1. Minimum range depends on acceptable measurement uncertainty which is 10 ppm-
meters. For example, for the level of uncertainty to be below 2% of range, the
minimum range would be 500 ppm-meters.
NOTICE
10 ppm CO = 12.5 mg/m
3
2. For increased sensitivity (reduced uncertainty of measurement), the path length
must be maximized.
3. Maximum range is 6,000 ppm-meters.
NOTICE
To correct ppm-meters to effective ppm, divide the path length (in meters).
2.5 Mechanical installation
The transmitter and receiver units are mounted on a site mounting flange on opposite
sides of the duct. To protect operators, Rosemount
™
recommends using an isolating valve
for ducts that operate at a higher than atmospheric pressure.
Use a stand-off pipe [nominal bore 3 in. (75 mm) - not supplied] between the duct and the
site mounting flange. The pipe should be long enough to clear the equipment from any
duct lagging; it also helps to insulate the equipment from any high duct temperatures.
Install
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