Patent ID: 7881829

Claim:
A mass flow controller, comprising: a flow rate sensor section that measures a flow rate of a fluid flowing through a flow channel and outputs a flow rate measurement signal indicating the measurement value; a flow rate control valve that is disposed on an upstream side or a downstream side of the flow rate sensor section; a control section that calculates an opening control signal to be supplied to the flow rate control valve based on a predetermined calculation formula including at least a flow rate measurement value indicated by said flow rate measurement signal and a flow rate setting value, which is a target value, as parameters and outputs said opening control signal; and a pressure sensor section that detects pressure of said fluid on the upstream side or the downstream side of said flow rate sensor section and outputs a pressure detection signal indicating the pressure value, wherein said control section uses different calculation formulas for a changing period, which is a predetermined period from a point in time when said flow rate setting value changes by a predetermined amount or more, and a stable period, which is the remaining period, and at least in said stable period, said calculation formula further includes said pressure value as a parameter, wherein further comprising: a flow rate output section that performs a predetermined calculation on said flow rate measurement value and outputs a flow rate indicative value which performs different calculations on the flow rate measurements value in the changing period and the stable period.