Airflow Sensors Microbridge Mass Airflow/Unamplified AWM 2000 Series Figure 1 Heater Control Circuit FEATURES 1 Bidirectional sensing capability 1 Actual mass air flow sensing 1 Low differential pressure sensing The AWM2000 Series microbridge mass airflow sensor is a passive device comprised of two Wheatstone bridges. The heater control circuit in Figure 1 is required for operation per specifications. The sensing bridge supply circuit in Figure 2 is also required for operation per specifications. These two circuits are not on board the package and must be supplied in the application. The differential amplifier in Figure 3 is a useful interface for the sensing bridge. It can be used to introduce the gain and to introduce voltage offsets to the sensor output as referenced in Equation 1. Figure 2 Sensing Bridge Supply Circuit Figure 3 Differential Instrumentation Amplifier Circuit Note: For applications sensing hydrogen or helium, see Application Note 3, page 131. Equation 1: VoJ ( )( )( ) 2R2+R1 R1 where V offsetJVS 68 R4 R3 V2-V1 +V offset ( ) R6 R6+R5 Honeywell 1 Sensing and Control 1 1-800-537-6945 USA 1 F1-815-235-6847 International 1 1-800-737-3360 Canada Airflow Sensors Microbridge Mass Airflow/Unamplified AWM2000 Series AWM2000 SERIES ORDER GUIDE (Performance Characteristics @ 10.01 0.01 VDC, 25C) Catalog Listings AWM2100V AWM2150V Flow Range (Full Scale) 200 sccm 30 sccm Pressure Range (See Application Note #1) AWM2200V AWM2300V 1000 sccm 4.0N H2O (10 mBar) Output Voltage @ Trim Point 30 mV @ 100 sccm 11.8 mV @ 25 sccm 20 mV @ 2N H2O 50 mV @ 650 sccm Null Voltage Shift, Typ. +25 to -25C, +25 to 85C 0.20 mV 0.20 mV 0.20 mV 0.20 mV Output Voltage Shift, Max. +25 to -25C +25 to +85C +2.5% Reading -2.5% Reading +5% Reading -5% Reading +22% Reading (Note 2) -22% Reading +5% Reading -5% Reading Repeatability & Hysteresis, Max. 0.35% Reading 0.35% Reading 0.35% Reading 1% Reading Min. Typ. Max. Excitation (VDC) (Note 1) 8.0 100.01 15 Power Consumption (mW) -- 30 50 Null Voltage (mV) -1.0 0.0 +1.0 Response Time (msec) -- 1.0 3.0 Common Mode Pressure (psi) -- -- 25 Sensor Resistance (k) Pin 2-Pin 1, Pin 6-Pin 1 -- 5 -- Sensor Current (mA) Pin 2-Pin 1, Pin 6-Pin 1 -- -- 0.6 Temperature Range Operating: -25 to +85C (-13 to +185F); Storage: -40 to +90C (-40 to +194F) Termination 2,54 mm (.100N) centers, 0,635 mm (0.025N) square Weight (grams) 10.8 Shock Rating 100 g peak (5 drops, 6 axes) Airflow Notes: 1. Output Voltage is ratiometric to supply voltage. 2. Temperature shifts when sensing differential pressure correlates to the density change of the gas over temperature. See Application Note 1. 3. Maximum allowable rate of flow change to prevent damage: 5.0 SLPM/1.0 sec. MOUNTING DIMENSIONS (for reference only) Honeywell 1 Sensing and Control 1 1-800-537-6945 USA 1 F1-815-235-6847 International 1 1-800-737-3360 Canada 69 Airflow Sensors Microbridge Mass Airflow/Unamplified OUTPUT FLOW VS INTERCHANGEABILITY (Note 1) AWM2100V AWM2000 Series Performance Characteristics @ 10.0 0.01 VDC, 25C AWM2150V AWM2200V (Note 2) AWM2300V Press. Flow Nom. mBar sccm mV Tol. mV Press. Flow Nom. mBar sccm mV Tol. mV Flow Press. Nom. sccm N H2O mV Tol. mV Press. Flow Nom. mBar sccm mV Tol. mV 0.49 200 44.50 4.25 53 30 14.0 2.5 120 4.00 31.75 3.50 3.4 1000 55.50 3.70 0.35 150 38.75 3.00 36 20 9.5 1.5 90 3.00 26.75 2.50 2.4 800 52.90 3.50 0.21 100 30.00 1.50 17 10 5.0 1.5 60 2.00 20.00 1.20 1.8 650 50.00 2.50 0.09 50 16.50 2.50 9.8 5 2.5 1.0 30 1.00 11.20 1.80 0.83 400 42.50 3.00 0.00 0 0.00 3.20 0.00 1.00 7.4 4 2.0 1.0 0 0.00 1.00 0.31 200 29.20 -0.09 -50 -16.50 4.50 6.2 3 1.5 1.0 -30 -1.00 -11.20 3.00 0 0 0.00 1.00 -0.21 -100 -30.00 5.00 5 2 1.0 1.0 -60 -2.00 -20.00 3.30 -0.31 -200 -28.90 15.00 -0.35 -150 -38.80 7.65 2.5 1 0.5 0.8 -90 -3.00 -26.75 5.30 -0.83 -400 -41.20 26.00 -0.49 -200 -44.50 9.75 0 0 0.0 0.6 -120 -4.00 -31.75 7.00 -1.6 -600 -48.20 29.50 -9.8 -5 -2.5 2.0 -2.4 -800 -52.20 32.50 -53 -30 -14.0 5.0 -3.4 -1000 -55.00 36.00 Notes: 1. Numbers in BOLD type indicate calibration type, mass flow or differential pressure. Tolerance values apply to calibration type only. 2. Differential pressure calibrated devices are not recommended for flow measurement. Use flow calibrated devices for flow measurement. OUTPUT CURVES 70 Honeywell 1 Sensing and Control 1 1-800-537-6945 USA 1 F1-815-235-6847 International 1 1-800-737-3360 Canada