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gasQSTM flonic V2 (Ex)

Microelectromechanical gas quality measurement device. Based on its CMOS chip microthermal flow sensor in combination with a sonic nozzle and an on/off valve, thermal conductivity, heat capacity and specific gravity of the gas is measured. From these values, e.g. calorific value, methane number or Wobbe Index are correlated.

Compared to process gas chromatographs, the standard analytical tool to determine gas compositions, this stand-alone device needs no recalibration, no reference gas, is robust, compact in size and in- expensive. It is ideally suited for application fields like natural gas vehicles (NGVs), industrial burners or co-generation plants.


Measuring range:Hs1=28.0...50.0MJ/m3
Accuracy:Calorific value1 (Hs, n)≤ ± 1 MJ/mn3
Relative density1≤ ± 0.005
Wobbe index1 (Ws, n)≤ ± 1 MJ/mn3
Methane number ± 3 absolute
Repeatability2: ± 0.5 MJ/mn3 / ± 0.003 / ± 0.5 MJ/mn3 / ± 2 absolute
Measuring time:≥ 30 seconds
Measuring interval:adjustable (≥ 60 seconds)
Reaction time:T90 within 3 measuring intervals
Gas consumption:ca. 0.1 ln/measuring interval
Temperature range:-10 ... +55 °C
Media:dry, neutral gases (10-μm-filtering)
Inlet pressure range:4.5 bar to 6.0 bar absolute
Permissible overload / burst pressure:9.0 bar absolute
Counterpressure on outlet side:≤ 1.4 bar absolute
Gas connections:G1/8 internal threads
Weight: 2.0 kg
Dimensions (l x b x h): 213 x 80 x 137 mm
ATEX Certificate: Ԑx II 2G Ex ib IIC T4 Gb (SEV 18 ATEX 0111 X)
Output signal: Modbus-RTU (EIA-485 2-wire) 3 4
Supply voltage (Power supply): +10.5 to +36 Vdc (Mems AG MINI-PS-12-24DC/5-15DC/2-X)
Power requirement: ≤1.0W
Degree of protection: IP42

1 Reference conditions 25 °C, 0 °C, 1013.25 mbar
2 Statistical scattering value with 2 sigma of 48 measuring points
3 Factory settings Modbus: 19200 bps, even parity bit + 1 stop bit, Slave address: 0x01
4 Factory settings units and reference conditions: MJ/mn3, kg/mn3, 25 °C, 0 °C, 1013.25 mbar

ATEX characteristics

Housing material: STANAL-32 EN AW-6023
[EN AW-Al Si1Sn1MgBi]
Sealing material: NBR

Supply circuit

Max. input voltage Ui: 15.75 VDC
Max. input current Ii: 0.723 A
Max. input power Pi: 2.84 W
Max. internal capacity Ci: 0.188 μF
Max. internal inductivity Li: 0.024 mH

GPIO circuit

Max. input voltage Ui: 28.0 VDC
Max. input current Ii: 0.1 A
Max. input power Pi: 0.7 W
Max. internal capacity Ci: 0.003 μF
Max. internal inductivity Li: 0.01 mH

RS485 resp. CAN circuit

Input circuit:

Output circuit:

Max. input voltage Ui: 7.5 VDC  
Max. input current Ii: 0.75 A  
Max. input power Pi: 1.4 W  
Max. internal capacity Ci: 1.1 μF 1.1 μF
Max. internal inductivity Li: 52 μH 52 μH
Max. output voltage Uo:   4.1 VDC
Max. output current Io:   0.091 A
Max. output power Po:   0.094 W
Max. external capacity Co:   7.9 μF
Max. external inductivity Lo:   0.2 mH


WARNING: For use in hazardous areas, the instrument must be connected to Zener barriers. Mems AG recommends the separation barriers Z713 (power supply), Z757 (communication) and Z728 (GPIO) from Pepperl+Fuchs.

WARNING: For protection level Ga the gas quality sensor enclosure must be installed protected against impact and friction.

WARNING: For calculation of the intrinsic safe RS485/CAN output circuit the internal capacitance of Ci = 1.1 μF and the internal inductance Li = 52 μH must be regarded.

Prices and orders

We would be happy to put together a personal offer for you at your request.