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Instruction Manual
IM-106-5500, Original Issue
August 2005
CCO 5500
4-8
Chopper Motor
Frequency
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.
YVals and Gas ppm 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.
Calibration Data 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.
4 ModFreq = 37.4 Hz
Mark/Space = 0.984
4 CO (0) = 3287ppm
CO (60) = 3289ppm
4 Y = 6060 Yx = 6058
Y (60) = 6058
4 Kwkg 9877
Kcal 9865
4 Rx T
o
F = 30.3
Kcal T
o
F = 30.1