Teledyne 9110AH Instruction Manual page 54

TELEDYNE Model 9110AH NO Analyzer Operator Manual, 01620, Rev. F
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Reaction Cell Pressure (RCEL)
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 reading is about 5 in-Hg-A at sea level for the
standard pump.
Sample Pressure (SAMP)
The sample pressure is measured by one of the pressure sensors on the sensor board. The
sample pressure typically runs slightly below atmospheric pressure. Sample pressure will
change with varying atmospheric pressure (like the weather) because the sensor is an absolute
pressure sensor. It will also change with altitude.
NO , NO Slope and Offset Values (NO SLOPE, NO OFFS, NO SLOPE, NO OFFS)
x x x
The slope (m) and intercept (b) coefficients of 2 (NO and NO) straight line equations (y = mx
x
+ b) determine the calibration of the M9110AH. The slope parameter(m) can be thought of as a
gain term which determines the steepness of the calibration curve. The offset (b) parameter
compensates for differences in the background signal of the NO and NO channels. This is
x
primarily due to the background of the converter.
These parameters contain valuable information about the quality and validity of the calibration.
For example the NO and NO slope values should not differ by more than 0.1 from each other.
x
Larger values indicate a flow imbalance such as a leak or problems with the converter. Refer to
Section 7.9 Calibration Quality for details on how to use these values.
Time (TIME)
This is the output of the internal time of day clock.
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