AWM90000 Series Mass flow sensor for gases FEATURES · Ranges 0...±200 sccm1 or 0...±2 "H2O (0...±5 mbar) · Bidirectional sensing · Actual mass flow sensing · Low differential pressure sensing SERVICE To be used with dry gases only The AWM series is NOT designed for liquid flow and will be damaged by liquid flow through the sensor SPECIFICATIONS ELECTRICAL CONNECTION Maximum ratings Supply voltage2 8 to 15 V typ. 10 ±0.01 V Power consumption 50 mW Temperature limits Operating Storage -25 to 85°C -40 to 90°C Mechanical shock 100 g (5 drops, 6 axes) 1 2 3 4 5 6 7 8 Note: 1 sccm denotes standard cubic centimeters per minute 2 Output voltage is ratiometric to supply voltage December 2007 / 592 1/6 www.sensortechnics.com AWM90000 Series Mass flow sensor for gases FLOW SENSOR CHARACTERISTICS3 VS = 10 ±0.01 V, TA = 25°C Part no. Flow range (full scale) AWM92100V ±200 sccm Pressure range ±2 "H2O AWM92200V Output voltage @ trim point Max. flow change4 5.0 l/sec 77 mV @ 200 sccm 5.0 l/sec 38 mV @ 2 "H2O PERFORMANCE CHARACTERISTICS VS = 10 ±0.01 V, TA = 25°C Characteristics Zero offset Repeatability and hysteresis (combined) Min. Typ. Max. Unit -15 0 15 mV ±0.35 %FSO AWM92100V AWM92200V ±0.1 Ratiometricity error2 Temperature effects5 Offset Span -25 to 85 °C6 -25 to 25 °C 25 to 85 °C ±2.07 -3.0 AWM92200V 25 5 AWM92100V ±1.08 Sensor resistance (pin 1 - pin 2, pin 1 - pin 8) -30 1.5 %FSO % reading %FSO 5 1.75 Sensor current Common mode pressure mV 8 AWM92100V AWM92200V Response time % reading ±0.30 1.0 % reading 2.2 kOhm 0.6 mA 3.0 ms 25 p si Notes: 2 Output voltage is ratiometric to supply voltage 3 A 5 micron filter is recommended for all devices. 4 Maximum allowable rate of flow change to prevent damage. 5 Temperature shifts in differential pressure devices are mostly due to the density change of the gas over temperature. 6 Shift is relative to 25 °C. 7 Assumes low TCR bridge resistance used (pins 2 and 8). 8 Requires recommended Rc value of 1K Ohm is used (pins 3 to 7) and typ. heater control circuit. Maximum current Rh. 2/6 December 2007 / 592 www.sensortechnics.com AWM90000 Series Mass flow sensor for gases OUTPUT FLOW VS INTERCHANGEABILITY VS = 10 ±0.01 V, TA = 25°C OUTPUT CURVES December 2007 / 592 3/6 www.sensortechnics.com AWM90000 Series Mass flow sensor for gases HEATER CONTROL CIRCUIT SENSING BRIDGE SUPPLY CIRCUIT 6 A) 10 V Ra Rb 24.9 kOhm 5 7 1 kOhm Rh 3 B) 2 24.9 kOhm 8 Rr 4 1 Note: Circuits required for operation per specifications. Circuits are not on board the sensor. A) Customer supplied 1 kOhm resistor (affects temperature compensation and span voltage). B) Customer supplied 24.9 kOhm matched bridge resistors (affects null output voltage). Output is measured differentially from pins 8 to 2. HEATER CONTROL CIRCUIT (suggested) DIFFERENTIAL INSTRUMENTATION AMPLIFIER CIRCUIT (OPTIONAL) 2 R + R1 R4 (V2 − V1 ) + VOffset VO = 2 R1 R3 R6 where VOffset = VS R6 + R5 4/6 December 2007 / 592 www.sensortechnics.com AWM90000 Series Mass flow sensor for gases OUTLINE DRAWING 13.08 (0.515) 8x3.05 (0.12) 8x0.25 (8x0.01) 7x2.54 (0.10) 8x0.51 (0.02) 15.75 (0.62) 17.02 (0.67) 12.57 (0.50) 1.02 (0.04) 27.94 (1.10) 1.14 (0.05) 32.39 (1.28) 2x Ø 1.17 (2x Ø 0.05) 2.79 (0.11) 13.21 (0.52) 2x Ø 4.70 (2x Ø0.19) 10.41 (0.41) mass: approx. 5.6 g December 2007 / 592 Ø 3.81 (Ø 0.15) 19.3 (0.76) 30.48 (1.20) dimensions in mm (inches) 5/6 www.sensortechnics.com AWM90000 Series Mass flow sensor for gases GAS CORRECTION FACTORS9 Gas type Helium (He) Hydrogen (H2) Argon (Ar) Nitrogen (N2) Oxygen (O2) Ai r Nitric oxide (NO) Carbon monoxide (CO) Methane (CH4) Ammonia (NH3) Nitrous oxide (N2O) Nitrogen dioxide (NO2) Carbon dioxide (CO2) Correction factor (approx.) 0.510 0.710,11 0.95 1.0 1.0 1.0 1.0 1.0 1.1 1.1 1.35 1.35 1.35 Notes: 9 Gas correction factors are referenced to nitrogen (N2) as calibration gas type. Approximate gas correction factors are provided as guidelines only. Individual gas types may perform differently at temperature extremes and varying flow rates. 10 When sensing Hydrogen (H2) or Helium (He) it may be necessary to power the mass flow sensor using increased supply voltage: Hydrogen typ. 12 V, Helium typ. 15 V 11 Hydrogen (H2) flow measurement requires the use of a special sensor. These devices provide normal operation when sensing hydrogen flow and are designated with an "H" at the end of the order number. ORDERING INFORMATION Flow range Dry gas ±200 sccm AWM92100V Pressure range Dry gas ±2 "H2O (±5 mbar) AWM92200V Sensortechnics reserves the right to make changes to any products herein. Sensortechnics does not assume any liability arising out of the application or use of any product or circuit described herein, neither does it convey any license under its patent rights nor the rights of others. 6/6 December 2007 / 592 www.sensortechnics.com