Apparatus and method for displaying mass flow controller pressure
A mass flow controller includes a pressure sensor that senses pressure within the mass flow controller and displays the pressure. The pressure display may be local, mounted directly to the mass flow controller, or it may be connected through a link to the mass flow controller for remote display.
1. A mass flow sensor for operation with a mass flow controller that includes an outlet control valve for controlling fluid flow through the controller, the mass flow sensor comprising:
a thermal mass flow sensor, including a sensor bypass, configured to sense flow of fluid into an inlet of the controller and to produce a mass flow signal representative of said flow;
a pressure sensor configured to sense fluid pressure in a volume between the thermal mass flow sensor bypass and the outlet control valve;
an electronic controller configured to provide a closed loop control signal for said outlet control valve based on said mass flow signal; and
a display configured to display the fluid pressure sensed by said pressure sensor.
2. The mass flow sensor of claim 1 wherein the mass flow controller includes a housing which encloses the mass flow sensor and the display is supported by said housing.
3. The mass flow sensor of claim 1 wherein the display is connected to the mass flow controller through a serial data link.
4. The mass flow sensor of claim 1 wherein the display is connected to the mass flow controller through a parallel data link.
5. The mass flow sensor of claim 1 wherein said electronic controller is also configured to provide a network interface that permits the execution of mass flow controller active diagnostics from a device connected to the network.
6. The mass flow sensor of claim 5 wherein active diagnostics code operational with the mass flow controller's electronic controller includes code to enable the manipulation of operational signals from a device connected to the network.
7. The mass flow sensor of claim 5 wherein active diagnostics code operational with the mass flow controller's electronic controller includes code to enable the manipulation of diagnostic signals from a device connected to the network.
8. The mass flow sensor of claim 5 wherein active diagnostics code operational with the mass flow controller's electronic controller includes code to enable the monitoring of operational signals from a device connected to the network.
9. The mass flow sensor of claim 5 wherein active diagnostics code operational with the mass flow controller's electronic controller includes code to enable the monitoring of diagnostic signals from a device connected to the network.
10. The mass flow sensor of claim 5 further comprising:
on-line diagnostics code operational with the mass flow controller's electronic controller that enables on-line monitoring of operational signals from a device connected to the network.
11. The mass flow sensor of claim 5 further comprising:
on-line diagnostics code operational with the mass flow controller's electronic controller that enables on-line monitoring of diagnostic signals from a device connected to the network.
12. The mass flow sensor of claim 5 further comprising:
on-line diagnostics code operational with the mass flow controller's electronic controller that enables on-line manipulation of diagnostic signals from a device connected to the network.
13. The mass flow sensor of claim 5 further comprising:
on-line diagnostics code operational with the mass flow controller's electronic controller that enables on-line manipulation of operational signals from a device connected to the network.
14. A mass flow controller comprising:
a thermal mass flow sensor, including a sensor bypass, configured to sense the flow of fluid into an inlet of the controller and to produce a mass flow signal representative of said flow;
a pressure sensor configured to sense fluid pressure in a volume between the thermal mass flow sensor bypass and an outlet control valve;
a display configured to display the pressure sensed by said pressure sensor; and
an electronic controller configured to produce a closed loop control signal for the outlet control valve based on said mass flow signal, wherein said electronic controller comprises a dual-processor controller that is configured to provide a network interface that permits the execution of mass flow controller active diagnostics from a device connected to the network.
15. The mass flow controller of claim 14 wherein active diagnostics code operational with the mass flow controller's electronic controller includes code to enable the manipulation of operational mass flow controller signals from a device connected to the network.
16. The mass flow controller of claim 14 wherein active diagnostics code operational with the mass flow controller's electronic controller includes code to enable the manipulation of diagnostic mass flow controller signals from a device connected to the network.
17. The mass flow controller of claim 14 wherein active diagnostics code operational with the mass flow controller's electronic controller includes code to enable the monitoring of operational mass flow controller signals from a device connected to the network.
18. The mass flow controller of claim 14 wherein active diagnostics code operational with the mass flow controller's electronic controller includes code to enable the monitoring of diagnostic mass flow controller signals from a device connected to the network.
19. The mass flow controller of claim 14 further comprising:
on-line diagnostics code operational with the mass flow controller's electronic controller that enables on-line monitoring of mass flow controller signals from a device connected to the network.
20. The mass flow controller of claim 14 further comprising:
on-line diagnostics code operational with the mass flow controller's electronic controller that enables on-line manipulation of mass flow controller signals from a device connected to the network.
21. The mass flow controller of claim 14 wherein the network interface comprises a web server that enables a web-enabled device connected to the world wide web to execute on-line diagnostics from the web-enabled device.
22. The mass flow controller of claim 14 wherein the mass flow controller is self-calibrating.
23. A mass flow controller comprising:
a thermal mass flow sensor, including a sensor bypass, configured to sense the flow of fluid into an inlet of the controller and to produce a mass flow signal representative of said flow;
a pressure sensor configured to sense fluid pressure in a volume between the thermal mass flow sensor bypass and an outlet control valve;
a display configured to display the pressure sensed by said pressure sensor; and
an electronic controller configured to produce a closed loop control signal for the outlet control valve based on said mass flow signal, wherein said electronic controller comprises a dual-processor controller that is configured to provide a network interface that permits the execution of mass flow controller active diagnostics from a device connected to the network;
wherein said dual processors include a processor configured to operate in a deterministic mode and a processor configured to operate in a non-deterministic mode and the deterministic processor is configured to produce said closed loop control signal for an outlet valve.
24. The mass flow controller of claim 23 wherein the deterministic processor is configured to acquire one or more sensor readings.
25. The mass flow controller of claim 24 wherein the mass flow sensor is a thermal mass flow sensor, including a sensor bypass, configured to sense the flow of fluid into the inlet of the controller and the mass flow controller further comprises a pressures sensor configured to sense the fluid pressure in the volume between the thermal mass flow sensor bypass and the control valve, and said deterministic processor is configured to acquire a pressure signal produced by said pressure sensor and to compensate the sensed inlet flow rate sensed by said mass flow sensor using the pressure signal to thereby produce a compensated measure of the rate of fluid flow out of the controller.
26. The mass flow controller of claim 25 wherein the deterministic processor is configured to compute the time rate of change of pressure within the volume between the sensor bypass and the outlet control valve, and to use this time rate of change of pressure to produce the compensated measure of the rate of fluid flow out of the controller.