Airflow Sensors AWM 2000 Series Microbridge Mass Airflow/Unamplified Figure 1 Heater Control Circuit FEATURES 1 Bidirectional sensing capability 1 Actual mass air flow sensing 1 Low differential pressure sensing Figure 2 Sensing Bridge Supply Circuit The AWM2000 Series microbridge mass airflow sensor is a passive device com- prised of two Wheatstone bridges. The heater control circuit in Figure 1 is re- quired for operation per specifications. The sensing bridge supply circuit in Fig- ure 2 is also required for operation per specifications. These two circuits are not on board the package and must be sup- plied in the application. The differential Figure 3 amplifier in Figure 3 is a useful interface Differential Instrumentation Amplifier Circuit for the sensing bridge. It can be used to introduce the gain and to introduce volt- age offsets to the sensor output as refer- enced in Equation 1. Note: For applications sensing hydrogen or helium, see Application Note 3, page 131. Equation 1: 2R +R R 2 1 4 V J V -V +V offset o 2 1 R R ()1 ( 3)( ) R 6 where V offsetJV S R R 6+ 5 () 68 Honeywell1 Sensing and Control 1 1-800-537-6945 USA1 F1-815-235-6847 International 1 1-800-737-3360 CanadaAirflow Airflow Sensors AWM2000 Series Microbridge Mass Airflow/Unamplified AWM2000 SERIES ORDER GUIDE (Performance Characteristics 10.01 0.01 VDC, 25C) Catalog Listings AWM2100V AWM2150V AWM2200V AWM2300V Flow Range (Full Scale) 200 sccm 30 sccm 1000 sccm Pressure Range (See Application Note 1) 4.0N H O (10 mBar) 2 Output Voltage Trim Point 30 mV 100 sccm 11.8 mV 25 sccm 20 mV 2N H O 50 mV 650 sccm 2 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 +2.5% Reading +5% Reading +22% Reading (Note 2) +5% Reading +25 to +85C -2.5% Reading -5% Reading -22% 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 (kW) 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) 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) Honeywell1 Sensing and Control 1 1-800-537-6945 USA1 F1-815-235-6847 International 1 1-800-737-3360 Canada 69