Airflow Airflow Sensors AWM5000 Series High Flow Mass Airflow/Amplified FEATURES 1 Linear voltage output 1 Venturi design 1 Remote mounting capability 1 Active laser trimming improves inter- change ability 1 Separate gas calibration types: Ar (argon) N (nitrogen) or 2 CO (carbon dioxide) 2 In-Line Flow Measurement AWM5000 Series Microbridge Mass Air- flow Sensors feature a venturi type flow Figure 1 housing. They measure flow as high as 20 standard liters per minute (SLPM) while inducing a maximum pressure drop of 2.25N H O. The microbridge chip is in di- 2 rect contact with the flow stream, greatly reducing error possibilities due to orifice or bypass channel clogging. Rugged, Versatile Package The rugged plastic package has been designed to withstand common mode pressures up to 50 psi, and the small sensing element allows 100 gs of shock without compromising performance. The included AMP compatible connector provides reliable connection in demand- ing applications. On-board Signal Conditioning Each AWM5000 sensor contains circuitry Figure 2 which performs amplification, lineariza- tion, temperature compensation, and gas calibration. Figure 1 (Heater Control Cir- cuit) and Figure 2 (Sensor Bridge Circuit and Amplification Linearization Circuit) il- lustrate the on-board electrical circuitry for the AWM5000 Series. A 1 to 5 VDC linear output is possible for all listings regardless of flow range (5, 10, 15, or 20 SLPM) or calibration gas (nitrogen, car- bon dioxide, nitrous oxide, or argon). All calibration is performed by active laser trimming. Honeywell1 Sensing and Control 1 1-800-537-6945 USA1 F1-815-235-6847 International 1 1-800-737-3360 Canada 79Airflow Sensors AWM5000 Series Highflow Mass Airflow/Amplified SPECIFICATIONS (Performance Characteristics 10.0 0.01 VDC, 25C) AWM5101 AWM5102 AWM5103 AWM5104 Flow Range (Note 3) 0-5 SLPM 0-10 SLPM 0-15 SLPM 0-20 SLPM Suffix - Calibration gas VA - Argon (Ar) VC - Carbon dioxide (CO ) VN - Nitrogen (N ) 2 2 Min. Typ. Max. Excitation VDC 8 100.01 15 Power consumption (mW) 100 Response time (msec) 60 Null output VDC 0.95 1 1.05 Null output shift -20 to 70C 0.050 VDC .200 VDC Common Mode Pressure (psi) 50 Temperature range -20 to +70C, (-4 to 158F) Weight 60 grams (2.12 oz.) Shock ratings 100 g peak, 6 msec half-sine (3 drops, each direction of 3 axes) Output laser trim point 5 VDC Full Scale Flow Output voltage shift +20 to -25C, +20 to 70C Suffix VA or VN 7.0% Reading, Suffix VC 10.0% Reading Linearity error (2) 3.0% Reading (max.) Repeatability & Hysteresis 0.5% Reading (max.) Connector (Included) Four pin receptacle MICRO SWITCH (SS12143)/AMP (103956-3) Leak rate, max 0.1 psi/min. at static condition, (Note 2) Notes: 1. Linearity specification applies from 2 to 100% full scale of gas flow range, and does not apply to null output at 0 SLPM. 2. The AWM5000 series product has a leakage spec of less than 0.1 psi per minute at 50 psi common mode pressure. If during installation, the end adapters are twisted with respect to the flowtube, this may compromise the seal between the o-ring and the flowtube and may cause a temporary leak. This leak might be as high as 1 psi or might remain in specification. It will self-reseal as the o-ring takes a new set. Approximately 85% of the leakage will dissipate in 24 hours. Within 48 hours, complete recovery will take place. 3. SLPM denotes standard liters per minute, which is a flow measurement referenced to standard conditions of 0C/1 bar (sea level), 50% RH. NOTICE AWM5000Chimney Effect AWM microbridge mass airflow sensors detect mass airflow caused by heat transfer. The thermally isolated microbridge structure consists of a heater resistor positioned between two temperature sensing resistors. The heater resistor maintains a constant temperature, 160C above ambient, during sensor operation. Airflow moving past the chip transfers heat from the heater resistor. This airflow warms the downstream resistor and cools the upstream resistor. The temperature change and the resulting change in resistance of the temperature resistors is proportional to the mass airflow across the sensing element. When the sensor is mounted in a vertical position, under zero flow conditions, the sensor may produce an output that is the result of thermally induced convection current. This occurrence is measurable in the AWM5000 Series, particularly in the 5 SLPM versions. When designing the sensor into applications where null stability is critical, avoid mounting the sensor in a vertical position. 80 Honeywell1 Sensing and Control 1 1-800-537-6945 USA1 F1-815-235-6847 International 1 1-800-737-3360 Canada