In one aspect, fuel inventory data characterizing a level of fuel stored at a fuel storage facility can be received from a sensor in operable communication with the fuel storage facility. Flow meter data characterizing an amount of fuel dispensed from the fuel storage facility by a fuel dispenser nozzle can be received from a flow meter in fluid communication with the fuel dispenser nozzle and the fuel storage facility. Fuel transaction data characterizing the dispensing of fuel by the fuel dispenser nozzle and the dispensing of the fuel by one or more additional fuel dispenser nozzles in fluid communication with the fuel storage facility can be received. An estimate of meter drift characterizing a change in calibration of the flow meter can be determined based on the fuel inventory data, the flow meter data, and the fuel transaction data. The estimate of meter drift can be provided.

A self-correcting pressure-based mass flow control apparatus includes outlet pressure sensing to enable correction for non-ideal operating conditions. Further the mass flow control apparatus having a fluid pathway, a shutoff valve in the fluid pathway, a reference volume in the fluid pathway, a first pressure measuring sensor in fluid communication with the reference volume, a first temperature measuring sensor providing a temperature signal indicative of the fluid temperature within the reference volume, a proportional valve in the fluid pathway, and a second pressure measuring sensor in fluid communication with the fluid pathway.

A self-correcting pressure-based mass flow control apparatus includes outlet pressure sensing to enable correction for non-ideal operating conditions. Further the mass flow control apparatus having a fluid pathway, a shutoff valve in the fluid pathway, a reference volume in the fluid pathway, a first pressure measuring sensor in fluid communication with the reference volume, a first temperature measuring sensor providing a temperature signal indicative of the fluid temperature within the reference volume, a proportional valve in the fluid pathway, and a second pressure measuring sensor in fluid communication with the fluid pathway.

Provided are systems and methods for line volume calibration, and measurement of fluid samples delivered to an interrogation point. In various embodiments, a known fluid volume comprising a sample line fluid and a secondary fluid is delivered to a fluid boundary sensor. The fluid boundary sensor assists in determining the position of the boundaries between the various fluids, and the positions of these boundaries are used to determine the sample line fluid volume.

Provided are systems and methods for line volume calibration, and measurement of fluid samples delivered to an interrogation point. In various embodiments, a known fluid volume comprising a sample line fluid and a secondary fluid is delivered to a fluid boundary sensor. The fluid boundary sensor assists in determining the position of the boundaries between the various fluids, and the positions of these boundaries are used to determine the sample line fluid volume.

Aspects generally relate to methods, systems, and apparatus for conducting a calibration operation for a plurality of mass flow controllers (MFCs) of a substrate processing system. In one aspect, a corrected flow curve is created for a range of target flow rates across a plurality of setpoints. In one implementation, a method of conducting a calibration operation for a plurality of mass flow controllers (MFCs) of a substrate processing system includes prioritizing the plurality of MFCs for the calibration operation. The prioritizing includes determining an operation time for each MFC of the plurality of MFCs, and ranking the plurality of MFCs in a rank list according to the operation time for each MFC. The method includes conducting the calibration operation for the plurality of MFCs according to the rank list and during an idle time for the substrate processing system.

Aspects generally relate to methods, systems, and apparatus for conducting a calibration operation for a plurality of mass flow controllers (MFCs) of a substrate processing system. In one aspect, a corrected flow curve is created for a range of target flow rates across a plurality of setpoints. In one implementation, a method of conducting a calibration operation for a plurality of mass flow controllers (MFCs) of a substrate processing system includes prioritizing the plurality of MFCs for the calibration operation. The prioritizing includes determining an operation time for each MFC of the plurality of MFCs, and ranking the plurality of MFCs in a rank list according to the operation time for each MFC. The method includes conducting the calibration operation for the plurality of MFCs according to the rank list and during an idle time for the substrate processing system.

A multi-chamber rate-of-change flow meter system and methods for operating the same are disclosed. The multi-chamber rate-of-change flow meter system includes a collection of N chambers, means for drawing a gas into or out of the collection of N chambers, N pressure sensors corresponding one of the N chambers, and means for redistributing the gas among the chambers. A measurement module is coupled to the pressure sensors to obtain a rate of change of pressure in each of the chambers due to the redistribution of the gas and calculate a flow rate of the gas flowing into or out of the collection of N chambers based upon the rate of change of pressure in each of the chambers.

A multi-chamber rate-of-change flow meter system and methods for operating the same are disclosed. The multi-chamber rate-of-change flow meter system includes a collection of N chambers, means for drawing a gas into or out of the collection of N chambers, N pressure sensors corresponding one of the N chambers, and means for redistributing the gas among the chambers. A measurement module is coupled to the pressure sensors to obtain a rate of change of pressure in each of the chambers due to the redistribution of the gas and calculate a flow rate of the gas flowing into or out of the collection of N chambers based upon the rate of change of pressure in each of the chambers.

A method of obtaining the output flow rate of the flow rate controller according to an aspect is provided. The method including a first step of outputting gas whose flow rate is adjusted according to a designated set flow rate from the flow rate controller, in a state where the diaphragm mechanism is opened; a second step of adjusting the diaphragm mechanism so that the pressure in the second pipe is the target pressure value, in a state where the output of gas from the flow rate controller is continued in the first step; and a third step of obtaining the output flow rate of the flow rate controller by using a pressure value and a temperature value in the tank, after the pressure in the second pipe is set to the target pressure value in the second step.