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Common CO2 Gas Analyzer Features (SBA-4, SBA-5, EGM-4 and WMA-4)

Calibration

The design of our CO2 gas analyzers (SBA-4, SBA-5, EGM-4 and WMA-4) ensures an inherent calibration stability that has been confirmed by over 25 years experience in gas analysis technology.  Our analyzers do not require CO2 recalibration (we recommend periodic checks to confirm system integrity).  The analyzers employ a non-dispersive, infrared measurement technique, coupled with microprocessor-based signal processing to achieve excellent stability and specificity to CO2.  Our innovative "Auto-Zero" technology ensures fast warm-up, long term stability, accuracy and analyzer calibration. It also minimizes the effects on span (gas sensitivity) of sample cell contamination, source aging, changes in detector sensitivity and changes in pre-amplifier gain.

Measurement Ranges

All CO2 gas analyzers can be supplied with two different optical benches.  One bench is designed for measurement of CO2 in the ranges of 0-1,000 ppm up to 0-30,000 ppm and another optimized for 0-50,000 ppm and 0-100,000 ppm  For users that want to recalibrate the gas analyzer to a new level, this can easily be achieved as long as it is within the range for that particular optical bench.

Flexible, Versatile User Interface

Our analyzers are extremely powerful and versatile instruments.  A range of accessories can be used with our gas analyzers enhancing measurement capability.  Refer to the table below to see which accessories are compatible with the SBA-4, SBA-5, EGM-4 and WMA-4.

Software

Screen shotMost PP Systems' analyzers are supplied with a Windows® based software program for transferring and logging sensor data (not available for use with SBA-5 at this time). The sensor data may be recorded manually or automatically depending on user specified settings. Stored records (ASCII) can be later imported into your favorite spreadsheet program for further analysis.

On-line help is available to guide you every step of the way.

 

 

 

 

 

 

Product Specification

Specification SBA-4 SBA-5 EGM-4 WMA-4
Analysis Method

Non-dispersive infrared configured as an absolute absorptiometer with microprocessor control of linearization.

 

Ö

 

Ö

 

Ö

 

Ö

Measurement Ranges
  • 0-1,000 ppm (µmol mol-1)
  • 0-2,000 ppm (µmol mol-1)
  • 0-5,000 ppm (µmol mol-1)
  • 0-10,000 ppm (µmol mol-1)
  • 0-20,000 ppm (µmol mol-1)
  • 0-30,000 ppm (µmol mol-1)
  • 0-50,000 ppm (µmol mol-1)
  • 0-100,000 ppm (µmol mol-1)

Custom ranges up to 100,000 ppm upon request.

 

Ö

 

Ö

 

 

Ö

 

Ö

Automatic temperature & pressure compensation

Ö

Ö

Ö

Ö

Accuracy

< 1% of span concentration over the calibrated range, but limited by the accuracy of the calibration gas mixture

 

Ö

 

Ö

 

Ö

 

Ö

Linearity

< 1% throughout the range.

Ö

Ö

 

Ö

Ö

Stability

Automatic zero at regular intervals, corrects for sample cell contamination, source and detector ageing and pre-amplifier gain changes.

 

Ö

 

Ö

 

 

Ö

 

Ö

Sampling Pump Optional

Also requires an electrical kit.

Optional

 

Integral 6V DC Pump Integral 12V AC Pump
Flow Rate 200-500 ml/min recommended 200-500 ml/min recommended Fixed at 350 ml/min (Approximate) Adjustable from 200-1,000 ml/min
Flow Meter No No No Yes
Environmental Sensor Inputs 5 input channels (connection through terminal block) 1 input channel(connection through terminal block) 2 input/output connectors (15 pin) 5 input channels (connection through terminal block)
Air Filter Optional Optional Filtered sample line (hydrophobic) Filtered sample line (hydrophobic) with water trap
Calibration

Default value preset in factory (built-in linearization).

Potentiometer adjustment User programmable Calibration through keypad Calibration through keypad
CO2 Control

High and low set points.

Not available

Not available

Ö

Ö

Alarm

Not available

Not available

Visual and audio Visual (LED) and audio
Real Time Clock

Accuracy > 1 minute per month at 25o C, operating temperature 0-70o C.  Automatic correction for month end and leap years.

Not available

Not available

 

Ö

 

Ö

Recording

Manual (by key press) or automatic at user selected intervals between 1 and 250 minutes.

Not available

Not available

Ö

Ö

Data Storage

Not available

Not available

512K Battery backed RAM (1,000 records) 512K Battery backed RAM (1,250 records)
Response Time

Display/Analog Output: 1.6 seconds

Ö

Ö

Ö

Ö

Analog Output (CO2 only)

4-20 mA, 0-1V, 0-2V, 0-3V, 0-4V, 0-5V (linear)

Ö

Dual 0-5V linear (CO2 and H2O)

4-20 mA (CO2 only)

Ö

Ö

Digital (RS232) Output

9600 baud/8 data bits, 1 start bit/2 stop bits/no parity.  ASCII format.

Ö

Ö

Also includes USB

Ö

Ö

Windows Software

Ö

Not available

Ö

Ö

Display

High contrast, 2 x 16 character LCD

No display

No display

Ö

Ö

Power Supply 12 VDC (User supplied) 6-18 VDC (user supplied) 12V, 2.0 Ah lead acid or 12V NiMH rechargeable battery 85V AC - 264V AC (47 Hz - 63 Hz) or 12V DC
Power Consumption 12V@ 0.7A (warm-up)

12V@ 0.5A (normal operation)

8 W (warm up)

1-3 W (Normal operation and dependent on ambient temperature)

12V @ 0.7A (warm-up)

12V @ 0.4A (normal operation)

115V @ .15A (maximum)

230V @ .075A (maximum)

12V @ 1.3A (maximum), 0.75A (normal operation)

Gas Connections

Two barbed fittings (inlet and exhaust) for use with 1/8" (.125") ID tubing

 

Ö

 

Ö

 

Ö

 

Ö

Housing None.  Supplied as board only (PCB Type FR4) None.  Supplied as board only (PCB Type FR4).

Optional aluminum enclosure is available (TBD).

High impact, aluminum enclosure High impact, IP65 enclosure
Dimensions 15.5 cm (W) x 17 cm (L) x 3 cm (H) 7.5 cm (W) x 12 cm (L) x 3.5 cm (H) 18 cm (W) x 21.5 cm (H) x 6.3 cm (D) 23 cm (W) x 15 cm (H) x 14 cm (D)
Weight 0.3 kg  0.2 kg 1.9 kg 1.9 kg
 
Accessory Compatibility SBA-4 SBA-5 EGM-4 WMA-4
SRC-1 Soil Respiration Chamber Not compatible Not compatible Ö Not compatible
STP-1 Soil Temperature Probe Not compatible Not compatible Ö Not compatible
CPY-2 & CPY-4 Canopy Assimilation Chamber Not compatible Not compatible Ö Not compatible
PMR-5 Steady State Porometer Not compatible Not compatible Ö Not compatible
Humidity Sensor Ö Ö Ö Ö
PAR-1 Probe & PAR Sensor Ö Ö Ö Ö
TRP-1 & TRP-2 Temperature/PAR Probe Ö Ö Ö Ö
OP-1 & OP-2 Oxygen Sensor Ö Ö Ö Ö
  SBA-4 Data Sheet   EGM-4 Data Sheet WMA-4 Data Sheet

PP Systems is continuously updating its products and reserves the right to amend product specifications without notice.

Auto-Zero

All PP Systems' CO2 infra-red gas analyzers 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 minimizes the effects on span (gas sensitivity) of sample cell contamination, source aging, changes in detector sensitivity and changes in pre-amplifier gain.

Our company considered using a 2 wavelength detector several years ago, but 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.

The only disadvantages to the auto zero approach is that the analyzer requires a flow, a solenoid valve and a chemical absorber (soda lime) which requires replacing at regular intervals. The advantages of an auto-zero system, in our opinion, far outweigh the disadvantages.