Teledyne 300M - Manual (Page 47)

Teledyne API Model 300M CO Analyzer Instruction Manual, 04033, Rev. A
4 SETUP MODE
This section describes the setup variables that are used to configure the analyzer.
4.1 Setup Mode Operation
ALL the setup variables are stored in the analyzer's EEPROM and are retained during power off
and generally when new software revisions are installed.
NOTE
If a variable is modified, but ENTR is not pressed, the variable will
not be changed and the analyzer will beep when EXIT is pressed.
4.2 Examining the Carbon Monoxide Formula Slope and
Offset
The slope and offset parameters can be examined by pressing the <TST or TST> buttons until
the slope and offset test functions appear. The slope and offset parameters are set only during
zero and span calibration routines. These parameters are used to adjust the span and zero values
to their exact values.
The current value of the Carbon Monoxide reading that is displayed on the front panel and
output on the D/A terminals on the back panel is computed as follows:
1. Every 160 msec, the analyzer takes a CO MEAS reading (i.e. a reading of the detector output
with the IR beam passing through the N
2
cell of the Gas Filter Wheel) and a CO REF reading
(i.e. a reading of the detector output with the IR beam passing through the CO Cell of the
Filter Wheel).
2. A raw (uncorrected, non-linearized) CO concentration value is calculated according to the
following equation:
concentration = gain_const x (1-CO_MEAS/CO_REF + Zero_Const)
3. Slope and offset corrections are made to the CO concentration according to the equation:
Corrected concentration =
Slope x Measured Concentration + Offset
4-1