| 摘要 |
<p>A method for controlling the gas flow within a digital mass flow controller. The method calculates a digitally enhanced flow rate signal that more accurately represents an actual flow rate through the digital mass flow controller. The digitally enhanced flow rate is calculated using a sensed flow rate signal output from a flow sensor, a scaled first derivative of the sensed flow rate signal, and a scaled, filtered second derivative of the sensed flow rate signal. A set-point signal is compared to the digitally enhanced flow rate signal to generate a digital error signal. The digital error signal is provided to a digitally realized PI (proportional integral) controller. The PI controller generates a digital control signal which is used to control a valve in the digital mass flow controller.</p> |
