Method and Apparatus for Integrated Pressure and Flow Controller

A method of controlling pressure of a fluid, comprising:

• controlling actuation of a control valve based on pressure detected by a distal pressure sensor and a pressure setpoint, the control valve controlling pressure of a fluid in a flow path, the distal pressure sensor detecting fluid pressure at a flow restrictor at a location distal from the control valve, the flow restrictor disposed in the flow path;
• and
• determining a mass flow rate based on pressure as detected by the distal pressure sensor and a proximal pressure sensor that detects fluid pressure at the flow restrictor at a location proximal to the control valve.

A method of controlling pressure of a fluid, comprising:

• controlling actuation of a control valve based on a pressure setpoint and pressure detected by one of an upstream pressure sensor and a downstream pressure sensor, the upstream pressure sensor detecting fluid pressure at a flow restrictor upstream of the flow restrictor, the downstream pressure sensor detecting fluid pressure at the flow restrictor downstream of the flow restrictor, the control valve controlling pressure of a fluid in a flow path, the flow restrictor disposed in the flow path;
• and
• determining a mass flow rate based on pressure as detected by the upstream and downstream pressure sensors.