M300EU | THEORY OF OPERATION |
(Addendum to M300EU Manual - P/N 04145) |
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10.THEORY OF OPERATION
10.1. MEASUREMENT METHOD
The information found in Section 10.1 of the M300E/EM Operators Manual (P/N 04288) is applicable to the M300EU with the following addition. It is recommended that you read that section before continuing.
10.1.1. AUTO-REFERENCE RATIO
The higher resolution of the M300EU makes it more susceptible then the M300E/EM to the effects of a variety of environmental conditions such as:
•Drift related to the age of the optical bench components ( e.g. the IR lamp, the IR detector, etc.)
•Variations in the temperature of the sample gas (affecting it density).
•Interferents, specifically CO2 and H2O.
The M300EU accounts for these issues by adding an additional component to the CO concentration calculation call the
This ratio is arrived at in the same manner as the measure/reference ratio (described in Section 10.1.3.2 of the M300E/EM Operators Manual) with the difference that that during the measurements that are to calculate the A- REF ratio, the gas stream is switched to pass through a scrubber that completely removes all CO from the sample gas. Therefore the measured difference between CO MEAS and CO REF represents the exact state of the sample gas and the optical bench’s sensors without CO present.
Figure 10-1: M300EU Gas flow during Auto-Reference Measurements
The analyzer averages the last five
Whenever an
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