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10.6 Internal Flow Transducer Specifications
Table 16 - Internal Flow Transducer - General Specifications
General specifications
The internal flow transducer contains two sensors, one flow sensor and the other to measure the temperature.
Each sensor has an independent nonlinear voltage output. To determine the mass flow of gas passing
through the transducer, the output voltage of each of the sensors is measured.
A microprocessor processes the results and calculates the flow using a specific algorithm.
The circuit that measures the flow is usually known as a thermal sensor or hot wire anemometer.
This flow transducer uses a heated wire sensor and maintained at a temperature of 150 ° C.
The velocity of the gas passing through the sensor determines the rate of heat transfer between the sensor
and the gas.
This heat transfer rate is translated into a voltage necessary to maintain the temperature at 150 ° C.
Consequently, this voltage is a function of the mass flow of gas passing through the sensor.
The heat transfer rate is also influenced by the gas temperature.
A thermistor circuit is used to measure the temperature of the gas and a correction is also made through
specific algorithm.
Reading range
Air: 0 to 300 SLPM
O
2
: 0 to 300 SLPM
Specified Tolerance
Air: 2.0% or 0.05 SLPM (whichever is greater)
O
2
: 2.0% or 0.05 SLPM (whichever is greater)
Resistance
< 2.5mbar
Gas temperature range
5 to 46°C
Humidity Range
Dry gas (< 10% UR)
Operating Pressure
Atmospheric pressure
Power supply
5V ± 10% sensor and 2.7V - 5.5V Eeprom
Response Time
< 2.5ms
Burst pressure
Above 100 psi
Weight
21g