| 摘要 |
<p>PURPOSE:To precisely perform flow rate control without being affected by ambient temperature. CONSTITUTION:The mass flow controller, which obtains flow rate data from the output of a bridge circuit and controls the flow rate of measurement gas flowing through a main gas flow passage is provided with a constant current circuit 21 which supplies a constant current to the bridge circuit, a compensation signal detection circuit which detects the voltage of the bridge circuit varying with the ambient temperature and obtains a signal of temperature compensation data V1 a reference data storage part 33 which stores reference data Vs obtained at reference temperature on the basis of the voltage of the said bridge circuit, a temperature compensating arithmetic part 34 which obtain zero-point compensation data by performing arithmetic of K1(V1-Vs)+K2¦V1-Vs¦ on the basis of the reference data Vs from the reference data storage part 33 and the temperature compensation data V1 from the compensation signal detection circuit 23, and an addition part 35 which adds the zero-point compensation data obtained by the temperature compensating arithmetic part 34 to the flow rate data, and compensates the zero of the flow rate data.</p> |
