• Selected distributed control systems: The use of distributed control
systems requires input/output (I/O) hardware and AMS software
which permit HART communications.
6. When the transmitter is configured without the LOI, you must calibrate and
diagnostically troubleshoot the transmitter using the HART or FOUNDATION
Fieldbus interface.
7. Optional blowback system: The blowback system periodically blows
instrument air back through the sample line filter and out the sample tube.
This clears out particulate and keeps the sample line filter from clogging.
1.2.5 System operation
The sensor housing and probe mount to a duct or process wall so that the probe
protrudes into the flue gas stream. An air powered eductor continuously pulls
samples of the process flue gas through the probe to a chamber in front of the
sensor housing where the sample passes the O
2
sensor and continues on the COe
sensor. Dilution air is provided to the COe sensor and reference air to the O
2
sensor. After the gas sample flows past the O
2
sensor and through the COe
sensor, it is drawn through the eductor where it mixes with the eductor air and
exits through exhaust back into the system.
The electronics housing contains the CPU and communication boards, which
convert the sensor inputs into 4-20 mA analog output signals. The CPU can also
initiate and perform calibrations. Solenoids can turn on and off three test gases
and instrument air. A flow meter between the electronics and sensor housings
regulates test gas flow to the sensors. Instrument air is separated into eductor
air, reference air, and dilution air. The instrument air solenoid does not allow air
flow until the heaters are up to temperature. This minimizes the amount of
sampled process flue gas being pulled into the cold sensors causing
condensation.
Description and specifications Manual
December 2022 00809-0500-4880
14 Emerson.com/Rosemount
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