Gases PRO Sensor Board (Calibrated)

This platform enables the user to implement pollution, air quality, industrial, environmental or farming projects with high requirements in terms of high accuracy, reliability and measurement range as the sensors come calibrated from factory. The Gases PRO line is available for both Waspmote and Plug & Sense!.

So we offer to our clients two different sensor boards in order to measure gas levels: Gases Sensor Board (Gases) and Gases PRO Sensor Board (Gases PRO).

Comparative between Gases and Gases PRO sensor boards:

• Gases PRO integrates 17 different gas sensors. Gases integrates 12. See the complete list of parameters in the tables below.

• Gases PRO is useful to measure the exact value in ppm's of a gas concentration. The Gases line provides just the level of concentration low / medium / high. Complete accuracy ranges are shown in the table below.

• Gases PRO is meant to be used in applications that require accurate readings and exact concentrations thus its sensors are more expensive than the Gases regular version that just provides average levels.

• A Particle Matter Sensor -commonly known as "Dust Sensor"- has been integrated in the Gases PRO board. This sensor allows to measure PM1, PM2.5, and PM10 particles. This sensor comes also calibrated from factory.

• Gases PRO is available for the Plug & Sense! product line (as Smart Environment PRO), while Gases is only offered for Waspmote OEM.

Should I choose Gases or Gases PRO?

Libelium created 2 different systems in terms of accuracy and pricing. The customer should consider Gases PRO if he needs maximum performance sensors for metering in accurate ppm or percentage. If the project just needs to detect gas presence or gas levels, the standard Gases Sensor Board can be enough.

The Gases PRO Sensor Board can read up to 17 gas sensors; it also has a high-end sensor for 3 parameters, temperature, humidity and pressure.

Gases PRO v3.0

Parameter	Range	Calibration *	Max consumption
Temperature	-40 to +85 ºC	Calibrated ±1 ºC (±0.5 ºC at 25 ºC)	2 μA @ 3V3
Humidity	0 to 100% HR	Calibrated ±3% RH (at 25 ºC, range 20 ~ 80% RH)	2.8 μA @ 3V3
Pressure	30 to 110 kPa	Calibrated ±0.1 kPa (range 0 ~ 65ºC)	4.2 μA @ 3V3
Carbon Monoxide for low concentrations CO	0 to 25 ppm	Calibrated ±0.1 ppm	312 μA @ 3V3
Carbon Dioxide CO2	0 to 5000 ppm	Calibrated ±50 ppm (range 0~2500 ppm) ±200 ppm (range 2500~5000 ppm)	85 mA @ 3V3
Molecular Oxygen O2	0 to 30%	Calibrated ±0.1%	402 μA @ 3V3
Ozone O3	0 to 18 ppm	Calibrated ±0.2 ppm	< 1 mA @ 3V3
Nitric Oxide for low concentrations NO	0 to 20 ppm	Calibrated ±0.2 ppm	< 1mA @ 3V3
Nitric Dioxide high accuracy NO2	0 to 20 ppm	Calibrated ±0.1 ppm	< 1mA @ 3V3
Sulfur Dioxide high accuracy SO2	0 to 20 ppm	Calibrated ±0.1 ppm	< 1mA @ 3V3
Ammonia for low concentrations NH3	0 to 100 ppm	Calibrated ±0.5 ppm	338 μA @ 3V3
Ammonia for high concentrations NH3	0 to 500 ppm	Calibrated ±3 ppm	338 μA @ 3V3
Methane and other combustible gases CH4	0 to 100% / LEL	Calibrated ±0.15% LEL	68 mA @ 3V3
Molecular Hydrogen H2	0 to 1000	Calibrated ±10 ppm	520 μA @ 3V3
Hydrogen Sulfide H2S	0 to 100 ppm	Calibrated ±0.1 ppm	352 μA @ 3V3
Hydrogen Chloride HCl	0 to 50 ppm	Calibrated ±1 ppm	341 μA @ 3V3
Hydrogen Cyanide HCN	0 to 50 ppm	Calibrated ±0.2 ppm	327 μA @ 3V3
Phosphine PH3	0 to 20 ppm	Calibrated ±0.1 ppm	361 μA @ 3V3
Ethylene Oxide ETO	0 to 100 ppm	Calibrated ±1 ppm	360 μA @ 3V3
Chlorine Cl2	0 to 50 ppm	Calibrated ±0.1 ppm	353 μA @ 3V3
Isobutane C4H10	-	-	-
Ethanol CH3CH2OH	-	-	-
Toluene C6H5CH3	-	-	-
Volatile Organic Compounds	-	-	-
Hydrocarbons	-	-	-
Particle Matter – Dust	0.35 to 40 μm (24 steps) (includes PM1, PM2.5 and PM10)	Calibrated	270+ mA @ 5 V

Accuracy values have been calculated at average conditions: 20ºC / 101300 Pa. Accuracy levels may differ with different temperature and pressure levels, aging and in presence of third type of gases which cause cross sensitivity. See the "Calibration" chapter for more detail.

Gases v3.0

Parameter	Range	Calibration	Consumption
Temperature	-40 to +85 ºC	Calibrated ±1 ºC (±0.5 ºC at 25 ºC)	2 μA @ 3V3
Humidity	0 to 100% HR	Calibrated ±3% RH (at 25 ºC, range 20 ~ 80% RH)	2.8 μA @ 3V3
Pressure	30 to 110 kPa	Calibrated ±0.1 kPa (range 0 ~ 65 ºC)	4.2 μA @ 3V3
Carbon Monoxide CO	30 to 1000 ppm	Not calibrated	3 mA @ 5V
Carbon Dioxide CO2	350 to 10000 ppm	Not calibrated	50 mA @ 5V
Molecular Oxygen O2	0 to 30%	Not calibrated	0 μA
Ozone O3	0.010 to 1 ppm	Not calibrated	34 mA
Nitric Oxide NO	-	-	-
Nitric Dioxide NO2	0.05 to 5 ppm	Not calibrated	26 mA
Sulfur Dioxide SO2	-	-	-
Ammonia NH3	10 to 100 ppm	Not calibrated	12 mA @ 5V
Methane and other combustible gases CH4	500 to 10000 ppm	Not calibrated	61 mA @ 5V
Molecular Hydrogen H2	500 to 10000 ppm	Not calibrated	61 mA @ 5V 46 mA @ 5V
Hydrogen Sulfide H2S	0.1 to 3 ppm	Not calibrated	61 mA @ 5V
Hydrogen Chloride HCl	-	-	-
Hydrogen Cyanide HCN	-	-	-
Phosphine PH3	-	-	-
Ethylene Oxide ETO	-	-	-
Chlorine Cl2	-	-	-
Isobutane C4H10	50 to 5000 ppm	Not calibrated	61 mA @ 5V
Ethanol CH3CH2OH	1 to 30 ppm 50 to 5000 ppm	Not calibrated	61 mA @ 5V
Toluene C6H5CH3	1 to 30 ppm	Not calibrated	61 mA @ 5V
Volatile Organic Compounds	30 to 400 ppm	Not calibrated	32 mA
Hydrocarbons	-	Not calibrated	61 mA @ 5V
Particle Matter – Dust	-	-	-

How are the Gases PRO sensors calibrated?

All the Gases PRO sensors are linear, so they behave according to a simple line like y = f(x) = m·x + c. On the other hand, the Gases Sensor Board sensors show a logarithmic response, which is harder to handle.

All the gas sensors for Gases PRO are calibrated by the sensor manufacturers, in their laboratories. A two-point calibration process is performed to get maximum accuracy, with controlled concentrations of gas in vacuum chambers. Due to the linear nature of the sensors, those 2 points are enough to correct the 2 possible drifts in m (slope) and c (constant offset). Our sensor manufacturers provide a calibration certificate for each individual sensor, with two calibration parameters. Libelium stores these parameters in an EEPROM, non-volatile memory chip inside each gas sensor. When the user performs a sensor reading, the software system designed by Libelium reads the sensor signal and the 2 parameters. All these 3 values are processed by the system. After this, a temperature compensation calculation is applied too. From this data we obtain the concentration value in ppm's (which is the final value we want to measure).

The Temperature, Humidity and Pressure sensor for Gases PRO is calibrated in factory too. There are 3 calibration points for temperature, 6 points for humidity and 9 points for pressure. These 3 parameters are automatically inter-compensated and this way the user gets extreme accuracy.