3) The signal from the oxygen sensor can be recorded from the BNC output
labeled
OXYGEN SENSOR
,
0-1V=0-100%
. The amplitude of the signal ranges
from 0 to 1 Volt DC which corresponds to a range of 0 to 100% oxygen, or 1mV
for each 0.01% oxygen. The ground of this output is common to the instrument
case and the power supply.
4) The signal from the carbon dioxide sensor can be recorded from the BNC
output labeled
CO2 SENSOR, 0.8-4V=0- 10%
. The amplitude of the signal
ranges from 0.8 to 4 Volt DC which corresponds to a range of 0 to 10% carbon
dioxide, or 1mV for each 0.01% oxygen.
Items Provided With the GA-200 Gas Analyzer
External filter with Luer–Lock fittings
Nafion sampling tube with Luer-Lock fittings
Power supply
GA-200A: One BNC-BNC cable, one BNC- Two wire cable
GA-200B: Two BNC-BNC cables
How the GA-200 Works
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.
How to Use the GA-200 Gas Analyzer
Prior to use, users must perform a two-point calibration of the oxygen and carbon
dioxide sensors.
Note: Warm up the GA-200 for at least 30 minutes. The input air filter must be
connected to avoid damaging the sensors.
Calibrating the O
2
and CO
2
Channels
The outputs of the oxygen and carbon dioxide sensors of the GA-200 are voltages
that are proportional to the concentrations of the gases being measured by the
analyzer. To determine the volumes of oxygen consumed and carbon dioxide
produced during metabolic testing, the voltage outputs of the sensors need to be
converted, by the recording software, to the percentages of these gases in the
GA-200 Gas Analyzer
iWorx Systems, Inc.
www.iworx.com
