Emerson IM-106-5500 Manual Do Utilizador

IM-106-5500, Original Issue

August 2005

CCO 5500

3-14

b. Set Values 

The normalizing data can be brought into the instrument in one of 3 
ways: 

1 By entering a fixed value via the 

keypad. This is suitable where the 
value is stable to about ±5%. 

2 If an INPUT UNIT is being used, all 

normalizing data can be 
transmitted via the serial data line. 

3 Using the 4-20 mA inputs within the 

processor to receive a 
measurement transducer data. The 
values at 4 mA and at 20 mA will 
be requested should this option be selected. 

With an integrated system the lead analyzer should have its 
normalizing parameters set to the 4-20 mA inputs. All the other 
analyzers must then be set to serial and the normalization 
parameters will be transmitted down the serial data highway. 

c. Temperature 

An analog input should always be used for temperature correction - 
this ensures that the flue gas temperature is being measured 
continuously and accurately. Connect the analog output of the 
temperature transducer into the Rosemount Analytical analyzer, and 
select the analog input option. This value is used to normalize the 
gas concentration measurement, and to correct for the effects of 
temperature on the IR absorption spectrum. 

If a fixed value input is used, then at flue gas temperature higher than 
572

o

F (300

o

C) the compensation algorithm will become less precise 

and instrument accuracy will deteriorate accordingly. This is not 
recommended. 

NOTE
If normalization is not required, the instrument must hold the temperature of 
the gas in the duct - analog input.

d. Oxygen 

To correct the data to standard levels of oxygen, an estimate of the 
oxygen at the point of measurement is required. If the oxygen level is 
being continuously measured, connect the analog output of the 
oxygen analyzer into the CCO 5500 analyzer, and select the analog 
input in the normalization menu. This input must be defined as either 
WET or DRY, depending on how the measurement is made. After the 
wet or dry has been defined the analog input values need defining, 
set the 4 mA and 20 mA values. If the oxygen level is relatively 
constant through all firing conditions, then a fixed (keypad) input may 
be used.