For over 30 years, PP Systems has been manufacturing high quality CO2/H2O infrared gas analyzers for researchers and customers from a wide variety of disciplines throughout the world. We are considered a leader in CO2/H2O infrared gas analysis measurement instrumentation and our analyzers are in use in over 100 countries worldwide. Our innovative Auto-Zero Measurement Principle ensures the greatest accuracy, reliability and long term stability that many of our customers have come to expect throughout the years.
Superb Reliability, Stability and Accuracy Of CO2 and H2O Measurement
All PP Systems’ CO2/H2O infrared gas analyzers feature an Auto-Zero facility. This feature, which occurs at regular intervals, allows for fast warm-up, adaptation to changing ambient conditions and excellent stability of the CO2 signal. The action of auto zeroing minimizes the effects on span (gas sensitivity) of sample cell contamination, source aging, changes in detector sensitivity and changes in pre-amplifier gain. Simply put, you should never have to worry about the accuracy of your CO2 calibration as long as the Auto-Zero is in use. Simple, periodic checks of the CO2 and H2O calibration are recommended.
Based on our extensive in-house testing, we concluded that true Auto-Zero instruments such as ours provided greater stability and reliability for the following reasons:
- Major effects of temperature are on the transmission characteristics of the interference filters and in 2 wavelength instruments, these are required to closely track.
- Dirt in the cells, changes in cell reflectivity, changes in source position or relative emission over the source surface can differentially affect the sensors.
- Changes in source temperature will affect the relative emissions at the two wavelengths.
- Cross sensitivity problems to other gases are increased as neither wavelength must be affected.
- Both sensors will require electronics and these must have identical temperature coefficients and must age exactly the same.
- Reliability must decline as the component count increases.
- Using two sensors degrades the signal/noise which is inversely proportional to the sensor area.
Therefore, for the reasons described above, we believe that the Auto-Zero measurement technique is best for all applications that demand the accuracy, reliability and long term stability.