Now you can control oxygen and carbon dioxide levels in research chambers with a response time of less than 1 second. Monitor up to four (4) animal or plant atmosphere environments with a single controller.

Here is a truly digital oxygen analyzer with analog and digital interfaces for control, display, and data-logging of oxygen and CO2 parameters.

The Oxigraf O2iR may be the chamber controller you need.

  • Fast response
  • Reliable laser diode technology
  • Pressure and temperature correction
  • Remote display and maintenance
  • Insensitive to movement
  • Coded password access
  • Sample flow monitor
Unit of Measure

Fast Response

N/A Modern process control requires fast response without overshoot. The Oxigraf chamber controller responds in less than a second. The transit time of the gas sample through the sampling tube may be 1 second per meter of sampling tube. To respond within 5 seconds, a monitor with a 1 second response time would need to be placed within 4 meters of the potential hazard. Electrochemical sensors may incorporate long averaging times, 20 or more seconds, for large, abrupt changes in oxygen concentration. Laser diode technology offers short response times to meet your control requirements.

Sample Flow Monitor

N/A The Oxigraf O2iR includes a sampling pump, hydrophobic filter, and flow sensor. The microprocessor controller maintains the flow at a constant value. Any flow blockage or pump failure is reported as a low flow fault. Filter impedance can also be measured to indicate a need for filter maintenance. Thus remote monitoring of the flow system is enabled. Pumps are available to provide sampling at atmospheres down to 200 mbar.

Temperature, Pressure and Humidity


An error budget must be established for oxygen process control. Humidity changes can cause a large variation in the oxygen measurement. A hot, wet day relative humidity of 50% at 37ºC (99ºF) corresponds to an absolute humidity of 3.2%. Such a water vapor dilution would cause a variation from the cold, dry air oxygen concentration of 20.9 to 20.2%, a change of 0.7%. If 19.5% is to be the alarm value, then variations from all other sources must be substantially less than 0.7% (the difference between 19.5 and 20.2%).

Therefore, temperature and pressure corrections are important. An oxygen sensor which measures oxygen partial pressure instead of concentration would report an oxygen variation of 2% with a 10% variation in barometric pressure. The Oxigraf sensor is corrected to within ±0.2% over pressure changes of 50% and temperature changes from 0 to 50ºC.

Remote Display

N/A The O2iR chamber controller includes various communication outputs of oxygen concentration, CO2 concentration, alarms, flow, and system status. It is essential for cost effective control to have both local and remote indication of chamber control operation. Another advantage of a remote display we call “remote maintenance”. A major cost of oxygen process controllers is the requirement for periodic maintenance and recalibration. With remote maintenance, site service and recalibration are no longer required to be periodic. Any system, power, flow or measurement faults will be flagged on a remote display, and service and calibration can be performed on an as-needed basis. For example, choosing an average oxygen concentration in humid air of 20.7%, the central monitor might flag measurements outside a range from 20.2 to 21.2% as requiring a calibration visit; with such a remote maintenance protocol, a periodic calibration frequency might be annual or less frequent.

Tunable Diode Laser Spectroscopy

N/A The Oxigraf O2iL is the next generation oxygen process controller. Laser diode absorption spectroscopy assures stable, long-life oxygen measurement: there are no electrochemical cells to replace or paramagnetic sensors to recalibrate. The laser diode, derived from high reliability telecommunications VCSEL (vertical cavity surface emitting laser) diode technology, is rated for more than 100,000 hours mean time to failure. The laser diode is thermally and electronically tuned to measure the absorption of oxygen at 763 nm, and also periodically measures the background to provide an automated zero. Pressure and temperature corrections are made to yield the correct oxygen concentration as the weather changes.

Insensitivity to Movement

N/A The Oxigraf technology has no moving parts, in contrast to paramagnetic technology. Laser diode technology will have no false alarms due to equipment vibration, mechanical accidents, or even earthquakes.

Code Access

N/A Control of the unit via the 12-key capacitive-touch panel can be restricted by use of a password. This permits access control for maintenance and unit calibration.

Measurement Performance

Sample Ports

N/A Option: 4 Standard: 1

Measurement Range

N/A 0-10% CO2 2% to 100% Oxygen


N/A ±0.5%

Cross Sensitivity

N/A 0.2% (XC mode)

Response Time

N/A 500 ms at 200 ml/min flow rate, additional low pass filtering programmable.

Ambient temperature Operating

N/A -10 to 50 ºC

Ambient Temperature Storage

N/A -20 to 60 ºC

Gas Inlet Temperature

N/A -10 to 50 ºC

Gas Pressure

N/A 750 to 1150 mbar


N/A 0 to 95%, non-condensing

Warm-up for Full Accuracy

N/A 5 min

Filter (Inlet)

N/A Hydrophobic PTFE inlet filter blocks any condensate.

Pump Sampling Rate

N/A Diaphragm pump up to 250 ml/min at 1010 mbar

User Interface

Display Resolution

N/A 0.1% O2 & CO2


N/A 16 x 2 character VFD, 8 mm character size


N/A Red lens flashing strobe


N/A 100 dB


N/A NEMA 4X rated non-metallic box with Lexan window, wall mounted.

Outside Dimensions

N/A 300 x 250 x 165 mm


N/A 8 Pound3.20 kg

Electrical Interface

Analog Output

N/A 4 to 20 mA (max 750 ohm load), range programmable for O2 and CO2

Serial Outputs

N/A RS232 (TXD, RXD, Ground), RS485 Modbus compatible


N/A SPDT, 5 Amps, 115 VAC or 24 VDC

Alarm Relay

N/A Programmable low limit or high limit, failsafe on/off


N/A 16 W typical 40 W max 50 to 60 Hz 85 to 264 VAC Optional 0.6 A typical Optional 1.5 A max Optional 24 to 32 VDC

Conduit connection


Power Connection

N/A Terminal strip

4-20 mA Connection

N/A Terminal strip

RS232 Connection

N/A Terminal strip and connector (Switchcraft EN3P3F)

RS485 Modbus Connection

N/A Terminal strip

Relay Connection

N/A Terminal strip


Low Calibration Point

N/A 20.9% Automatic & 0.04% CO2, Room Air(User programmable

High Calibration Point

N/A 100% O2, 10% CO2 (User programmable)