Ambient CO Monitor

The cross flow modulation type, infrared-absorption technology eliminates the need for adjusting optical alignment.
For the user, this means very stable and sensitive (5 ppm F.S.) measurements.

The APMA-370 uses an AS-type interference-compensating detector, and a purified reference gas. The reference gas is generated by purging the sample through an oxidation process, where an oxidizing catalyst burns the CO to CO₂. These features eliminate interference from other elements, resulting in highly accurate measurements.

The APMA-370 does not use such components as reflecting mirrors, that attract foreign matter. This means the optical bench stays clean assuring you of stable results over long periods of time.

Cross flow modulation, inflared (NDIR) absorption technology
Conventional technology uses an optical chopper to obtain modulation signals. Instead, the APMA-370 uses solenoid valve cross flow modulation. Fixed amounts of the sample gas and the reference gas are injected alternately into the measurement cell. With the cross flow-modulation method, if the same gas is used for both the sample gas and the refe-rence gas (e.g., zero gas could be used for both), no modulation signal will be generated. This has the great advantage that, in principle, when analyzing minute amounts of gas there is no generation of zero-drift. An additional advantage is that the elimi-nation of rotary sectors precludes the need for optical adjustment. These features assure greatly improved stability over long periods of measurement. A further improvement is that in the front chamber of the detector, the measurable components, including interference components, are detected; in the rear chamber, only interference components are detec-ted. By means of subtraction processing, the actual signal obtained is one that has very little interference.