This invention provides a mass flow controller that can prevent a flow
rate change due to a pressure change without sacrificing the speed of
response to a change of a flow rate setting value and can be used in a
system that can generate a crosstalk.
In order to provide the mass flow controller, the mass flow controller
has: a control section 5 that calculates an opening control signal to be
supplied to a flow rate control valve based on a predetermined
calculation formula including at least a flow rate measurement value and
a flow rate setting value as parameters and outputs the opening control
signal; and a pressure sensor section 4 that measures pressure of a fluid
on the upstream side or the downstream side of a flow rate sensor section
2 and outputs a pressure detection signal indicating the pressure value.
The control section 5 uses different calculation formulas for a changing
period, which is a predetermined period from a point in time when the
flow rate setting value changes by a predetermined amount or more, and a
stable period, which is the remaining period, and at least in the stable
period, the calculation formula further includes the pressure value as a
parameter.