Product Specification

Prime2 Infrared CO2 Sensor Description and Operation

The Prime2 sensor use the non-dispersive infrared method to detect the presence of carbon dioxide. The sensor contains an infrared radiation source, a dual element infrared detector, a unique optical waveguide into which gas diffuses and integrated ARM7 core microprocessor based electronics to provide a voltage output which is independent of the power supply polarity. The sensor can be configured to provide a linear voltage output, typically 0.4V 2.0V over range with respect to the negative supply pin, or a pellistor format output, typically mid supply at zero with the voltage output increasing with respect to the detector pin by 100mV at range.



In addition, the output can be read and the internal configuration can be accessed by a serial communications link. The communication link contacts are pads in the 3 pin version Prime2 and pins in the 5 pin version Prime2. The internal electronics perform all the functions of driving the optical parts of the sensor, extracting the detector signals, converting the signals to a concentration, applying temperature compensation and scaling the output. When in a pellistor configuration, the Prime2 can operate in existing pellistor circuitry subject to the power supply requirements. External components will be required to meet the power supply requirement when a Prime2 is used in constant current pellistor circuitry. The Prime2 is not currently Ex-approved so should be housed in a suitable Ex enclosure when used in Hazardous areas.



Prime2 Infrared CO2 Sensor Features

• Operates independent of supply polarity

• Voltage or pellistor mimic bridge output

• Operating voltage range 3.0V 5.0V

• Operating current 80mA typical

• Latest technology MEMS detectors

• Sensing ranges: 0-5000ppm CO2 up to 0-10%volume CO2

• All metal construction with isolated housing

• Small internal volume

• Flexible electronic configuration access

• User calibration also enabled by hardware connections

• Wide operating temperature range

• Fast response



Prime2 Infrared CO2 Sensor Performance

Unless otherwise stated all data was taken using: Supply voltage of 3.5V. Ambient temperature (between 20°C and 25°C). Ambient pressure (between 995 hPa and 1020 hPa). Gases diluted in nitrogen. Gas Flowrate 1litre/min across sensor face.



Supply voltage range:

3.0V - 5.0V

Power consumption

280mW typical

Default output range:

Pellistor mode:

Voltage mode:



0 - 100mV from mid supply relative to detector pin

0.4V - 2.0V

Warm up time:

To operation

To specification



< 60s

< 3 minutes

Nominal ranges:

0 - 5% volume CO2

0 - 5000ppm CO2

Response time (T90)

< 30s to a step change in gas concentration

Minimum resolution:

At zero

At range



< 0.5% of range

<2% of range

Zero repeatability:

± 1% of range

Accuracy:

± 3% of range up to 50% of range

± 5% of range above 50% of range

MTBF

> 5 years

Digital interface format:

8 data bits, 1 stop bit, no parity

Digital Interface Baud Rate:

38400 (default), 19200, 9600

Digital Interface Logic Levels:







V INL Input low voltage: <0.8V

V INH Input high voltage: >2.0V

V OL Output low voltage: <0.4V

V OH Output high voltage: >2.4V

Weight:

18.0 grams

Vibration:

Complies with EN61779-1

Relative humidity:

0 - 95% RH non-condensing

Operating temperature range:

-30°C to +60°C

Storage temperature range:

-40°C to +80°C

Operating pressure range:

700 - 1300 hPa





Prime IR Sensor Type

Sensing Ranges

Prime1

0-100% Lel Methane, 0-100% Lel Hydrocarbons, 0-100% Volume Methane

Prime2

0-2000ppm Carbon Dioxide to 0-10% Volume Carbon Dioxide

Prime3

10-100% Volume Carbon Dioxide

Prime4

0-100% Lel Acetylene

PrimePELL

True Pellistor replacement, 0-100% Lel, 3 Pins





