Emerson IM-106-5500 Manual Do Utilizador

IM-106-5500, Original Issue

August 2005

CCO 5500

4-8

The chopper blade should 'chop' the IR 
radiation at a frequency of about 37 Hz. This 
frequency is measured by the processor and 
can be displayed from this option. 

As the chopper blades interrupts the IR beam, the radiation is split into two - 
half the time the blade obscures the beam and half the time the beam radiates 
across the duct. The value of MARK/SPACE should be between 0.9 and 1.1 
where: 

MARK/SPACE = Time IR Beam Obscured/Time IR beam clear. 

A parameter 'Y' determines the calculation of the gas concentration - refer to 
Section 1, Principles of Cross-Duct Gas Analyzers.

As a check on the program operation, this 
parameter and the resulting raw gas 
calculation, may be interrogated here. 

The term Yx is the second averaging stack's 
held value, and the term Y(60) is the 60-second 
raw value from which all of the other averaging 
stacks are calculated. These gas values 
represent the raw gas data before averaging for the corresponding Y values. 
Also displayed by pressing the arrow keys are the Z values. These are 
adjusted Y values used to compensate for cross sensitivities in the 
measurement range. 

The calibration factors, determined during the 
calibration routine (Kcal), and the value 
currently being used (Kwkg) can be examined 
from this display. Should the two values be 
different, this indicates a change in instrument temperature between the time 
of calibration and the current temperature. Press one of the ARROW keys to 
examine the temperature information. 

Temperature has a small effect on the filter/gas 
cell characteristics compensated for by the 
instrument; temperature measurement is made 
within the receiver.