Attitude insensitive flow device system and method

1. A flow device comprising:

a processor;

a computer readable medium accessible by the processor, storing a set of computer instructions, wherein the set of computer instructions comprise instructions executable to:

receive an orientation signal;

receive a sensed flow signal; and

determine a flow through the flow device based on the sensed flow signal and the orientation signal.

2. The flow device of claim 1 , further comprising an orientation sensor connected to the processor that provides the orientation signal.

3. The flow device of claim 2 , wherein the orientation signal corresponds to the angle of a thermal mass flow sensor.

4. The flow device of claim 2 , further comprising a thermal mass flow sensor further comprising:

an inlet;

an outlet;

a bypass area in fluid communication with the inlet and the outlet;

a capillary tube in fluid communication with the bypass area;

an upstream sense element;

a downstream sense element; and

sensor logic connected to the upstream sense element, the downstream sense element and the processor that outputs the sensed flow signal.

5. A flow device comprising:

a processor;

a computer readable medium accessible by the processor, storing a set of computer instructions, wherein the set of computer instructions comprise instructions executable to:

receive an orientation;

receive a sensed flow; and

determine a flow through the flow device based on the sensed flow and the orientation;

wherein the set of computer instructions further comprise instructions executable to select an offset based on the orientation.

6. The flow device of claim 5 , wherein the flow through the flow device is determined based on the sensed flow and the offset.

7. The flow device of claim 5 , further comprising an orientation sensor operable to determine at least four orientations.

8. The flow device of claim 7 , wherein the offset corresponds to one of the at least four orientations.

9. A flow device comprising:

a processor;

a computer readable medium accessible by the processor, storing a set of computer instructions, wherein the set of computer instructions comprise instructions executable to:

receive an orientation;

receive a sensed flow; and

determine a flow through the flow device based on the sensed flow and the orientation;

wherein the computer instructions further comprise instructions executable to store a set of offsets, each offset from the set of offsets corresponding to a particular orientation.

10. The flow device of claim 9 , wherein each offset from the set of offsets further corresponds to a particular process fluid.

11. The flow device of claim 9 , wherein each offset from the set of offsets further corresponds to a particular pressure.

12. The flow device of claim 1 , wherein the set of computer instructions further comprise instructions executable to:

select an offset based on the orientation signal;

apply the offset to the sensed flow signal; and

generate an indicated flow.

13. The flow device of claim 12 , wherein the set of computer instructions further comprise instructions executable to:

receive a set point;

compare the indicated flow to the set point; and

generate a valve control signal based on a difference between the indicated flow and the set point.

14. The flow device of claim 1 , wherein the flow device is a mass flow meter.

15. The flow device of claim 1 , wherein the flow device is a mass flow controller.

16. A method for measuring a flow through a flow device comprising:

determining the orientation of a thermal mass flow sensor and providing an orientation signal indicative of the orientation;

determining a sensed flow and providing a sensed flow signal indicative of the sensed flow;

determining the flow through the flow device based on the sensed flow signal and the orientation signal; and

providing an output signal indicative of the flow through the flow device.

17. The method of claim 16 , wherein determining the orientation of the thermal mass flow sensor comprises determining the orientation of the thermal mass flow sensor using an orientation sensor.

18. The method of claim 16 , wherein the orientation sensor senses at least four orientations.

19. The method of claim 18 , further comprising selecting an offset, wherein the offset corresponds to one of the at least four orientations.

20. The method of claim 16 , further comprising:

storing a set of offsets, wherein each offset corresponds to a particular orientation.

21. The method of claim 16 , further comprising storing a set of offsets, wherein each offset corresponds to a particular orientation and process fluid.

22. The method of claim 16 , further comprising storing a set of offsets, wherein each offset corresponds to a particular orientation and pressure.

23. The method of claim 16 , further comprising:

selecting an offset based on the orientation signal; and

applying the offset to the sensed flow signal.

24. The method of claim 23 , further comprising:

generating an indicated flow based on the offset and the sensed flow signal;

receiving a set point;

comparing the indicated flow to the set point; and

generating a valve control signal based on a difference between the indicated flow and the set point.

25. The method of claim 16 , further comprising storing a set of offsets based on a device-by-device calibration.

26. The method of claim 16 , wherein the flow device includes a valve and restrictor, the method further comprising storing a set of offsets based on a calibration of one or more devices having a similar combination of valve and restrictor.

27. A computer program product comprising a computer readable medium storing a set of computer instructions, wherein the set of computer instructions comprise instructions executable to:

receive an orientation signal;

receive a sensed flow signal;

determine a flow through a flow device based on the sensed flow signal and the orientation; and

provide an output signal indicative of the flow through the flow device.

28. The computer program product of claim 27 , wherein the orientation signal is received from an orientation sensor.

29. The computer program product of claim 28 , wherein the orientation sensor senses at least four orientations.

30. The computer program product of claim 29 , wherein the set of computer instructions further comprise instructions executable to select an offset based on the orientation signal.

31. The computer program product of claim 27 , wherein the set of computer instructions further comprise instructions executable to store a set of offsets, wherein each offset corresponds to a particular orientation.

32. The computer program product of claim 27 , wherein the set of computer instructions further comprise instructions executable to store a set of offsets, wherein each offset corresponds to a particular orientation and process fluid.

33. The computer program product of claim 27 , wherein the set of computer instructions further comprise instructions executable to store a set of offsets, wherein each offset corresponds to a particular orientation and pressure.

34. The computer program product of claim 27 , wherein the set of computer instructions further comprise instructions executable to select an offset based on the orientation signal and apply the offset to the sensed flow signal.

35. The computer program product of claim 34 , wherein the set of computer instructions further comprise instructions executable to generate an indicated flow based on the sensed flow signal and the offset.

36. The computer program product of claim 35 , wherein the set of computer instructions further comprise instructions executable to:

receive a set point;

compare the indicated flow to the set point; and

generate a valve control signal based on a difference between the indicated flow and the set point.

37. A mass flow controller comprising:

a thermal mass flow sensor, further comprising,

an inlet;

an outlet;

a bypass area in fluid communication with the inlet and outlet;

a capillary tube in fluid communication with the bypass area;

an upstream sense element and a downstream sense element to sense flow in the capillary tube;

sensor logic connected to the upstream sense element and downstream sense element that outputs a sensed flow;

an orientation sensor that outputs an orientation of the thermal mass flow sensor;

a processor that receives the sensed flow and the orientation;

a computer readable medium accessible by the processor; and

a set of computer instructions stored on the computer readable medium, the set of computer instructions comprising instructions executable to:

receive the sensed flow;

receive the orientation;

select an offset based on the orientation;

generate an indicated flow based on the sensed flow and offset;

receive a set point;

compare the indicated flow to the set point; and

generate a valve control signal based on a difference between the indicated flow and the set point.