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WMA-4 Dual Channel CO2 Analyser

Part Number: AGA550Product Details

For over 25 years, PP Systems has been manufacturing high quality CO2 infrared gas analysers for researchers and customers from a wide variety of disciplines throughout the world. We are considered a leader in CO2 infrared gas analysis measurement instrumentation and our analysers 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. In addition, we offer a range of environmental probes for use with our analysers enhancing measurement capability.

WMA-4 CO2 Analyser
An ideal instrument for fixed installations requiring long term, continuous measurement (and control) of CO2. A two channel version is also available.

  • High precision, compact CO2 analyser
  • Accuracy: <1% of span concentration over calibrated range
  • Operation from AC and DC power inputs
  • Built-in sampling pump and flow meter
  • Automatic pressure and temperature compensation
  • Voltage, current and digital (RS232) output
  • Visual and audible alarm (high and low CO2)
  • Rugged IP65 enclosure
  • Custom, tactile keypad
  • Compatible with PID controllers for control of CO2
  • Integral data logging capability
  • Growth chambers
  • Environmental control rooms
  • Open top chambers (OTCs)
  • Greenhouses and nurseries
  • Incubators
  • Fruit storage
  • FACE sites
  • Breweries
  • CO2 leakage monitoring
  • Indoor air quality and safety
  • Industrial monitoring
Auto-Zero Measurement Principle
All PP Systems' CO2 infra-red gas analysers feature the 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 minimises the effects on span (gas sensitivity) of sample cell contamination, source aging, changes in detector sensitivity and changes in pre-amplifier gain.

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.

WMA-4 CO2 Analyser product brochure


Part Number: AGA550
Accuracy <1% of span concentration over the calibrated range but limited by the accuracy of the calibration gas mixture
Air Filter Filtered sample line (hydrophobic)
Alarm Visual (LED) and audio alarm
Analog Output 4-20 mA, 0-1V, 0-2V, 0-3V, 0-4V, 0-5V (Linear)
Analysis Method Non-dispersive infrared, configured as an absolute absorptiometer with microprocessor control of linearisation
Calibration Default value preset in factory (built-in initialisation). Automatic calibration by keypad if required.
CO2 Control High and low set points
CO2 Measurement Ranges 0-1000 ppm (µmol mol-1); 0-2000 ppm (µmol mol-1); 0-5000 ppm (µmol mol-1); 0-10000 ppm (µmol mol-1); 0-20000 ppm (µmol mol-1); 0-30000 ppm (µmol mol-1); 0-50000 ppm (µmol mol-1); 0-100000 ppm (µmol mol-1). Custom ranges up to 100000 ppm upon request. Measurements are automatically corrected for temperature and pressure.
Data Storage 512K Battery backed RAM (1250 records)
Digital (RS232) Output 9600 baud/8 data bits, 1 start bit/2 stop bits/ no parity. ASCII format.
Dimensions (W × H × D) 23cm × 15cm × 14cm
Display High contrast 2 × 16 character LCD
Environmental Sensor Interface 5 input channels are available for external sensors (terminal block)
Gas Connections Two barbed fittings (inlet and exhaust) for use with 1/8" (.125") ID tubing
Gas Flow Rate Through Analyser The recommended flow rate through the analyser is 200-500 ml/min. A flow meter is included for easy flow adjustment (200-1200 ml/min).
Housing High impact, IP65 enclosure
Keypad Custom, tactile keypad
Linearity <1% throughout the range
Power Consumption 115V @ 0.15A (maximum); 230V @ 0.075A (maximum); 12V @ 1.3A (maximum), 0.75A (normal operation)
Power Supply 85V AC to 264V AC (47 Hz to 63 Hz) or 12V DC
Real Time Clock Accuracy > 1 minute per month at 25°C, operating temperature 0-70°C. Automatic correction for month end and leap years.
Recording Manual (by keypress) or automatic at user selected intervals between 1 and 250 minutes
Response Time Display/Analog Output - 1.6 seconds
Sampling Pump Integral, long life 12V AC diaphragm pump
Stability Automatic Zero at regular intervals, corrects for sample cell contamination, source and detector ageing and pre-amplifier gain changes
Weight 1.9kg

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