Teledyne API Model 200A NOX Analyzer Instruction Manual, 02246, Rev. G, DCN 5247
Moly Temperature
The moly temperature is controlled by the computer. The nominal set-point is 315 ± 5 C. The
temperature sensor inside the moly is a type-J thermocouple. The thermocouple amplifier is
located on the STATUS/TEMP board. If the thermocouple breaks, the reading will go to 500 C
and turn off power to the heater.
Reaction Cell Pressure
The pressure in the reaction cell is measured by a solid state pressure sensor which measures
absolute pressure. Absolute pressure was chosen because it is an unambiguous measure of cell
pressure. This pressure will vary depending on several things.
1. The type of pump attached to the analyzer.
2. Variations in local weather will cause a ± 0.3in-Hg change in pressure.
3. The altitude of the analyzer will cause the cell pressure to change.
Nominal values are 3 to 10 in-Hg-A. Typical readings are about 5 in-Hg-A for the external
pump, and about 8 in-Hg-A or better for the internal pump.
Sample Pressure
The pressure in the sample inlet line is measured by a solid state pressure sensor which measures
absolute pressure. Absolute pressure was chosen because it is an unambiguous measure of
sample pressure. This pressure typically runs 0.5" or so below atmospheric pressure due to the
pressure drop in the sample inlet lines.
NOx, NO Slope and Offset Values
The coefficients of two (NOx and NO) straight line equations determine the calibration of the
M200A. The values of these parameters can be used to determine the quality of the calibration.
These 4 parameters contain valuable information about the quality and validity of the calibration.
Refer to Section 5.2.2.5 for more information on the formulas. Refer to Section 7.10 Calibration
Quality for details on how to use these values.
Time
This is an output of the M200A's internal time of day clock.
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