Instrument are generally Infrared Type with a spectral range selected generally used in the combustion chamber, furnace on flanged nozzle (narrow band selectivity).
Temperature sensed is directly proportional to the total energy released in the combustion process without error due to absorption in the various reactant gases or products of combustion.
The instrument comprise of an Infra Red detector, preamplifier, signal conditioner and necessary converter to provide 4-20mA DC output, integrated in a single unit which shall be located in a hazardous area class indicated elsewhere.
Instrument are mounted on combustion chamber using sight glass and isolation valve. To ensure minimum error in the measurement, the sight glass and isolating valve should be requested from the instrument vendor.
Electronics of the instrument are microprocessor based with non-volatile memory. Output from electronics can be 4-20mA DC proportional to the temperature. Necessary linearization is provided in the electronics. Local temperature display is available at the instrument.
Field calibration and system operational verification also possible. Instrument have adjustable zero and span controls and are provided with self-diagnostic features. Compensation for loss due to sight glass is also be provided in the electronics.
The enclosure for the field unit are generally explosion proof certified for use in hazardous area class which can provided with separate cable entries for signal and power.