The GA-200 is an analyzer that integrates a gas sampling system with sensors to measure and display the concentrations of oxygen and carbon dioxide in a sample as the percentage of a gas in the sample by volume. This method of expressing the concentration of a gas in a sample is also known as the percent volume fraction. In addition to the sampling and sensing systems in the GA-200, the unit has a fluorescent display used for programming the unit and observing measurements, a keypad for programming the unit’s operation and calibration, and analog outputs that allow the unit to be connected to data recording units like the IX-214.
Operating principleWhen measuring the concentrations of oxygen and carbon dioxide in a gas, a sample is pumped from the input port on the front panel of the GA-200, through the sample cell, and out an exhaust port on the back panel of the unit. Gas samples are drawn into the unit through an external filter on the input port that protects the sensors from contamination and through Nafion tubing on the filter that removes moisture from the samples that would affect the measurements and the units calibration.
The oxygen concentration of the gas in the sample cell is measured using laser diode absorption technology. The laser diode in the oxygen sensor produces light at a wavelength (760 nanometers) that is absorbed by oxygen. The light passes through the gas pumped into the sample cell and onto the surface of a detector. The output of the sensor is inversely proportional to the concentration of oxygen in the sample because the amount of light reaching the detector decreases as the concentration of oxygen in the sample increases. The GA-200 has a very fast response time that enables breath to breath analysis of gas concentrations because the unit analyzes the gas sample every 10 milliseconds, or 100 times per second. During each measurement interval, the analyzer is zeroed automatically by electronic tuning of the laser to a wavelength not absorbed by oxygen.
Ready to use
The GA-200 gas analyzer is calibrated at the factory and is ready to take measurements. Just connect the source of the gas sample to the gas analyzer with the proper connections and press the RUN key - the results will appear on the built-in screen, as shown below.