AWM2300V Flow Sensor 50 mV Output Voltage Trim Point 650 sccm 30 mW Power Consumption for Accurate Flow Monitoring

                                                                         AWM2300V Flow Sensor

GENERAL INFORMATION :

The AWM2000 Series Microbridge Mass Airflow Sensor is a passive device consisting of two Wheatstone bridges: one for closed loop heater control and one for the twin sensing elements. The heater control in Figure 1 is required for operation per specification. The sensing bridge supply circuit in Figure 2 is also required. The differential instrumentation amplifier in Figure 3 can be used to increase gain and introduce voltage offsets to sensor output.

MEDIA CONTAMINATION:

Dust has the effect of clogging the porous metal flow restrictor (AWM2200V only). Dust accumulation causes the pressure drop across the sensor to increase for any given flow rate

Clogging can be prevented by use of an inexpensive 5 micron filter upstream of the sensing element.

MASSFLOW vs. DIFFERENTIAL PRESSURE :

The microbridge chip is fundamentally a mass flow sensor chip using a thermal transfer mechanism. The more mass flowing past the chip, the more heat being transferred. The sensing range can be expanded when sensing a sampled flow of the main flow by decreasing the ratio of the main flow path’s diameter to the minimum diameter of the airflow tube within the sensor. Choking off the sampled flow results in reverse amplification, achieved by mechanical means. It is then possible to measure differential pressure proportional to mass flow. The greater the differential pressure, the more mass that flows. Variations in density of flowing media due to ambient pressure and temperature changes will change AWM2200V differential pressure sensor output in proportion to the change in absolute density. The other mass flow sensors are not affected by density changes.

SOLDERING INSTRUCTIONS Note:

sensor should be securely attached to PC board before soldering Hand soldering: 1. Use temperature controlled soldering iron with 3,2 mm (1/8 in) diameter tip. 2. Set temperature at 400 °C [750 °F]. Hold tip on terminal for 5 seconds maximum. 3. Use Type R flux rosin core solder and hand clean after soldering.

SOLDERING INSTRUCTIONS, continued Wave soldering:

1. Set solder temperature at 250 °C [480 °F] maximum. 2. Run belt at minimum of 1.54 m [5 feet] per minute. 3. Cover tube ends when cleaning.