Process control system and method with automatic fault avoidance

• US 6,473,660 B1
• Filed: 12/03/1999
• Issued: 10/29/2002
• Est. Priority Date: 12/03/1999
• Status: Expired due to Term

• Current Assignee: Schneider Electric Systems USA, Inc. (Schneider Electric SE)
• Original Assignee: The Foxboro Company (Schneider Electric SE)
• Inventors: Thibault, Richard L.
• Primary Examiner(s): Black, Thomas
• Assistant Examiner(s): Hartman, Jr., Ronald D
• Application Number:
  US09/454,053
• Time in Patent Office: 1,061 Days
• Field of Search: 700/79, 700/2-3, 700/82, 700/83, 700/19-20, 700/21, 709/210, 709/211, 714/2, 714/6, 714/11, 714/37
• US Class Current: 700/79
• CPC Class Codes: G05B 9/03 with multiple-channel loop, i.e. redundant control systems

Abstract

A control system incorporates components that automatically switch information sources in response to actual or potential degradation of information generated by them. Thus, a control system has first and second control components that generate first and second “source” signals, respectively, representing substantially identical or related process control variables. A third control component, which normally processes the first source signal, responds to actual or potential degradation of that signal for processing the second source signal in lieu of the first.

Claims

1. A control system comprising

a first set comprising plural control components, each control component generating a source signal representative of control variable, an identifier signal identifying that control variable, and a confidence signal indicative of any of actual and potential degradation of that source signal,

a second set comprising at least one control component that processes a selected source signal and that responds to any of actual and potential degradation that source signal by (i) identifying from the identifier signals an alternate source signal, and (ii) processing that alternate source signal in lieu of the selected source signal,

wherein the first and second sets have any of zero, one or more control components in common.

2. A control system according to claim 1, wherein at least the control component that generates the selected source signal is self-validating.

3. A control system according to claim 2, wherein the self-validating control component generates the confidence signal to be representative of any of a status of a value represented by the corresponding source signal and a status of the control component.

4. A control system according to claim 1, comprising one or more registries that are coupled to the control components in the first and second sets for storing the identifier signals.

5. A control system according to claim 4, comprising a plurality of distributed registries.

6. A control system according to claim 1, wherein the control components of the first and second sets are coupled by any of a bus, a network and other communications media.

7. A control system according to claim 6, wherein the control components of the first and second sets are coupled by communications media operable in accord with any of a Foundation Fieldbus standard, a Profibus standard, a DeviceNet™

standard, an InterBus™

standard and a Modbus®

standard.

8. A control system comprising

a first set comprising plural control components, each control component generating a source signal representative of control variable, and a confidence signal indicative of any of actual and potential degradation of that source signal,

one or more registries that store identifier signals, each identifying a control variable and any of a control signal or control component corresponding thereto,

a second set comprising at least one control component that processes a selected source signal and that responds to any of actual and potential degradation that source signal by (i) identifying from the identifier signals an alternate source signal, and (ii) processing that alternate source signal in lieu of the selected source signal,

wherein the first and second sets have any of zero, one or more control components in common,

wherein the registries, the control components of the first set and the control components of the second set are coupled by communications media operable in accord with any of a Foundation Fieldbus standard, a Profibus standard, a DeviceNet™

standard, an InterBus™

standard and a Modbus®

standard.

9. A process control system comprising

a first set comprising plural process control components, each process control component generating a source signal representative of process variable, an identifier signal identifying that process variable, and a confidence signal indicative of any of actual and potential degradation of that source signal,

a second set comprising at least one process control component that processes a selected source signal and that responds to any of actual and potential degradation that source signal by (i) identifying from the identifier signals an alternate source signal, and (ii) processing that alternate source signal in lieu of the selected source signal,

wherein the first and second sets have any of zero, one or more process control components in common.

10. A process control system according to claim 9, wherein at least the process control component that generates the selected source signal is a self-validating process control component.

11. A process control system according to claim 10, wherein the self-validating process control component generates the confidence signal to be representative of any of a status of a value represented by the corresponding source signal and a status of the process control component.

12. A process control system according to claim 9, comprising one or more registries that are coupled to the process control components in the first and second sets for storing the identifier signals.

13. A process control system according to claim 12, wherein the registries are distributed.

14. A process control system according to claim 9, wherein the process control components of the first and second sets are coupled by any of a bus, a network and other communications media.

15. A process control system according to claim 14, wherein the process control components of the first and second sets are coupled by communications media operable in accord with any of a Foundation Fieldbus standard, a Profibus standard, a DeviceNet™

standard, an InterBus™

standard and a Modbus®

standard.

16. A process control system comprising

a first set comprising plural process control components, each process control component generating a source signal representative of process variable, and a confidence signal indicative of any of actual and potential degradation of that source signal,

one or more registries that store identifier signals, each identifying a process variable and any of a control signal or process control component corresponding thereto,

a second set comprising at least one process control component that processes a selected source signal and that responds to any of actual and potential degradation of that source signal by (i) identifying from the identifier signals an alternate source signal, and (ii) processing that alternate source signal in lieu of the selected source signal,

wherein the first and second sets have any of zero, one or more process control components in common,

wherein the registries, the process control components of the first set and the process control components of the second set are coupled by communications media operable in accord with any of a Foundation Fieldbus standard, a Profibus standard, a DeviceNet™

standard, an InterBus™

standard and a Modbus®

standard.

17. A method of operating a control system, comprising

generating, with each control component in a first set of plural control components, a source signal representative of a control variable and confidence signals indicative of any of actual and potential degradation of that source signal,

storing, in one or more registries, one or more identifier signals that identify control variables and any of control signals and control component corresponding thereto,

with a control component of a second set that comprises at least one control component, processing a selected source signal and responding to any of actual and potential degradation that selected source signal by (i) identifying from the identifier signals in the registries an alternate source signal, and (ii) processing that alternate source signal in lieu of the selected source signal,

wherein the first and second sets have any of zero, one or more control components in common,

transferring information among any of the registries and the control components via a communications medium operable in accord with any of a Foundation Fieldbus standard, a Profibus standard, a DeviceNet™

standard, an InterBus™

standard and a Modbus®

standard.

18. A method of operating a process control system, comprising

generating, with each process control component in a first set of plural process control components, a source signal representative of process variable, an identifier signal identifying that process variable, and a confidence signal indicative of any of actual and potential degradation of that source signal,

with a process control component in a second set comprising at least one process control component, processing a selected source signal and responding to any of actual and potential degradation that source signal by (i) identifying from the identifier signals an alternate source signal, and (ii) processing that alternate source signal in lieu of the selected source signal,

wherein the first and second sets have any of zero, one or more process control components in common.

19. A method according to claim 18, wherein at least the process control component that generates the selected source signal is a self-validating process control component.

20. A method according to claim 19, comprising generating, with the self-validating process control component, the confidence signal to be representative of any of a status of a value represented by the corresponding source signal and a status of the self-validating process control component.

21. A method according to claim 18, comprising storing the identifier signals in one or more registries.

22. A method according to claim 21, wherein the registries are distributed about the process control system.

23. A method according to claim 18, comprising transferring information among any of the process control components via any of a bus, a network and other communications media.

24. A method according to claim 23, comprising transferring information among any of the process control components via communications media operable in accord with any of a Foundation Fieldbus standard, a Profibus standard, a DeviceNet™

standard, an InterBus™

standard and a Modbus®

standard.

25. A method of operating a process control system comprising

generating, with each process control component in a first set of plural process control components, a source signal representative of process variable and a confidence signal indicative of any of actual and potential degradation of that source signal,

storing identifier signals in one or more registries, each identifying a process variable and any of a control signal or process control component corresponding thereto,

with a process control component in second set comprising at least one process control component, processing a selected source signal and responding to any of actual and potential degradation of that source signal by (i) identifying from the identifier signals an alternate source signal, and (ii) processing that alternate source signal in lieu of the selected source signal,

transferring information among any of the registries and the control components via a communications medium operable in accord with any of a Foundation Fieldbus standard, a Profibus standard, a DeviceNet™

standard, an InterBus™

standard and a Modbus®

standard,

wherein the first and second sets have any of zero, one or more process control components in common.

26. A control system comprising

a first control component generating a first source signal,

a third control component that is in at least selective communication with the first control component,

the third control component processing the first source signal and responding to any of actual and potential degradation of that signal by selectively processing a second source signal, generated by a second control component, in lieu of the first source signal, such selective processing being in response to an identifier signal identifying the second source signal as representative of a control variable that is any of substantially identical to and related to a control variable represented by the first source signal.

27. A control system according to claim 26, wherein the first control component generates a confidence signal indicative of any of actual and potential degradation of the first source signal.

28. A control system according to claim 27, wherein the first control component is self-validating.

29. A control system according to claim 27, wherein the first source signal is a measurement.

30. A control system according to claim 29, wherein the first control component is self-validating sensor.

31. A control system according to claim 27, wherein the second control component generates an identifier signal identifying a control variable represented by the second source signal.

32. A control system according to claim 31, wherein the third control component processes the second source signal in lieu of the first source signal in response to a confidence signal indicative of any of actual and potential degradation of the first control signal and in response to an identifier signal identifying the second source signal as representative of a control variable that is any of substantially identical to and related to a control variable represented by the first source signal.

33. A control system according to claim 31, comprising a registry that stores the identifier signal.

34. A control system according to claim 33, wherein the third control component obtains the identifier signal from the registry.

35. A process control system comprising

a first process control component generating a first source signal,

a third process control component that is in at least selective communication with the first process control component,

the third process control component processing the first source signal and responding to any of actual and potential degradation of that signal by selectively processing a second source signal, generated by a second process control component, in lieu of the first source signal, such selective processing being in response to an identifier signal identifying the second source signal as representative of a control variable that is any of substantially identical to and related to a control variable represented by the first source signal.

36. A process control system according to claim 35, wherein the first process control component generates a confidence signal indicative of any of actual and potential degradation of the first source signal.

37. A process control system according to claim 36, wherein the first process control component is self-validating.

38. A process control system according to claim 36, wherein the first source signal is a measurement.

39. A process control system according to claim 38, wherein the first process control component is self-validating sensor.

40. A process control system according to claim 36, wherein the second process control component generates an identifier signal identifying the process variable represented by the second source signal.

41. A process control system according to claim 40, wherein the third process control component processes the second source signal in lieu of the first source signal in response to a confidence signal indicative of any of actual and potential degradation of the first control signal and in response to an identifier signal identifying the second source signal as representing a process variable that is any of substantially identical or related to the process variable represented by the first control signal.

42. A process control system according to claim 40, comprising a registry that stores the identifier signal.

43. A process control system according to claim 42, wherein the third process control component obtains the identifier signal from the registry.

44. A process control system comprising

a first field device generating a first source signal,

a process control component in communication with the first field device,

the process control component processing the first source signal and responding to any of actual and potential degradation of that signal by selectively processing a second source signal, generated by a second process control component, in lieu of the first source signal, such selective processing being in response to an identifier signal identifying the second source signal as representative of a control variable that is any of substantially identical to and related to a control variable represented by the first source signal.

45. A process control system according to claim 44, wherein the process control component is a controller.

46. A process control system according to claim 44, wherein the process control component is coupled with any of the first field device and the second field device by any of a bus, a network and other communications media.

47. A process control system according to claim 46, wherein process control component is coupled with any of the first field device and the second field device by communications media operable in accord with any of a Foundation Fieldbus standard, a Profibus standard, a DeviceNet™

standard, an InterBus™

standard and a Modbus®

standard.

48. A process control system according to claim 44, wherein the first source signal and the second source signal represent a characteristic of a same process element and a same process control component.

49. A process control system according to claim 48, wherein the first source signal and the second source signal represent related characteristics of any of a same process element and a same process control component.

50. A process control system according to claim 49, wherein the first field device generates a confidence signal indicative of any of actual and potential degradation of the first source signal.

51. A process control system according to claim 50, wherein the first field device is self-validating.

52. A process control system according to claim 50, wherein the first source signal is a measurement.

53. A process control system according to claim 52, wherein the first field device is self-validating sensor.

54. A process control system according to claim 50, wherein the second field device generates an identifier signal identifying the process variable represented by the second source signal.

55. A process control system according to claim 54, wherein the process control component processes the second source signal in lieu of the first source signal in response to a confidence signal indicative of any of actual and potential degradation of the first control signal and in response to an identifier signal identifying the second source signal as representing a process variable that is any of substantially identical or related to the process variable represented by the first control signal.

56. A process control system according to claim 54, comprising a registry that stores the identifier signal.

57. A process control system according to claim 56, wherein the process control component obtains the identifier signal from the registry.

58. A method of operating a control system, comprising the steps of

generating, with a first control component, a first source signal,

with a third control component processing the first source signal and responding to any of actual and potential degradation of that signal by selectively processing a second source signal in lieu of the first source signal, such selective processing being in response to an identifier signal identifying the second source signal as representative of a control variable that is any of substantially identical to and related to a control variable represented by the first source signal.

59. A method of operating a control system according to claim 58, comprising the step of generating, with the first control component, a confidence signal indicative of any of actual and potential degradation of the first source signal.

60. A method of operating a control system according to claim 59, wherein the first control component is self-validating.

61. A method of operating a control system according to claim 59, comprising the step of generating the first source signal as a measurement.

62. A method of operating a control system according to claim 61, wherein the first control component is self-validating sensor.

63. A method of operating a control system according to claim 59, comprising the step of generating, with the second control component, an identifier signal identifying the control variable represented by the second source signal.

64. A method of operating a control system according to claim 63, comprising the step of

responding to a confidence signal indicative of any of actual and potential degradation of the first control signal and to an identifier signal identifying the control variable represented by the second source signal as any of substantially identical and related to the control variable represented by the first source signal,

by processing, with the third control component, the second source signal in lieu of the first source signal.

65. A method of operating a control system according to claim 63, comprising the step of storing the identifier signal in a registry.

66. A method of operating a control system according to claim 65, comprising the step of using the third control component to obtain the identifier signal from the registry.

67. A method of operating a process control system, comprising the steps of

generating, with a first process control component, a first source signal,

with a third process control component, processing the first source signal and responding to any of actual and potential degradation of that signal by selectively processing a second source signal in lieu of the first source signal, such selective processing being in response to an identifier signal identifying the second source signal as representative of a control variable that is any of substantially identical to and related to a control variable represented by the first source signal.

68. A method of operating a process control system according to claim 67, comprising the step of generating, with the first process control component, a confidence signal indicative of any of actual and potential degradation the first source signal.

69. A method of operating a process control system according to claim 68, wherein the first process control component is self-validating.

70. A method of operating a process control system according to claim 68, comprising the step of generating the first source signal as a measurement.

71. A method of operating a process control system according to claim 70, wherein the first process control component is self-validating sensor.

72. A method of operating a process control system according to claim 68, comprising the step of generating, with the second process control component, an identifier signal identifying the process variable represented by the second source signal.

73. A method of operating a process control system according to claim 72, wherein the third process control component processes the second source signal in lieu of the first source signal in response to a confidence signal indicative of any of actual and potential degradation the first control signal and to an identifier signal identifying the second source signal as representing a process variable that is any of substantially identical and related to the process variable represented by the first source signal.

74. A method of operating a process control system according to claim 72, comprising the step of storing the identifier signal in a registry.

75. A method of operating a process control system according to claim 74, wherein the third process control component obtains the identifier signal from the registry.

76. A method of operating a process control system comprising

generating, with a first field device, a first source signal,

with a process control component, processing the first source signal and responding to any of actual and potential degradation of that signal by selectively processing a second source signal in lieu of the first source signal, such selective processing being in response to an identifier signal identifying the second source signal as representative of a control variable that is any of substantially identical to and related to a control variable represented by the first source signal.

77. A method of operating a process control system according to claim 76, wherein the process control component is a controller.

78. A method of operating a process control system according to claim 76, comprising communicating between the process control component and any of the first field device and the second field device by way of any of a bus, a network and other communications media.

79. A method of operating a process control system according to claim 78, comprising communicating between the process control component and any of the first field device and the second field device by communications media operable in accord with any of a Foundation Fieldbus standard, a Profibus standard, a DeviceNet™

standard, an InterBus™

standard and a Modbus®

standard.

80. A method of operating a process control system according to claim 76, wherein the first and second source signals represent like characteristics of any of a same process element and a same process control component.

81. A method of operating a process control system according to claim 80, wherein the first and second control signals represent related characteristic of any of a same process element and a same process control component.

82. A method of operating a process control system according to claim 81, comprising generating with the first field device a confidence signal indicative of any of actual and potential degradation the first source signal.

83. A method of operating a process control system according to claim 82, wherein the first field device is self-validating.

84. A method of operating a process control system according to claim 82, comprising the step of generating the first source signal as a measurement.

85. A method of operating a process control system according to claim 84, wherein the first field device is self-validating sensor.

86. A method of operating a process control system according to claim 82, comprising generating with the second field device an identifier signal identifying the process variable represented by the second source signal.

87. A method of operating a process control system according to claim 86, comprising

responding to a confidence signal indicative of any of actual and potential degradation the first control signal and to an identifier signal identifying the second source signal as representing a control variable that is any of substantially identical to and related to the control variable represented by the first source signal,

by processing, with the process control component, the second source signal in lieu of the first source signal.

88. A method of operating a process control system according to claim 86, comprising the step of storing the identifier signal in a registry.

89. A method of operating a process control system according to claim 88, comprising the step of using the process control component to obtain the identifier signal from the registry.

90. A control system comprising

a plurality of field devices, each generating a source signal representative of a control variable, an identifier signal identifying that control variable, and a confidence signal indicative of any of actual and potential degradation of that source signal,

at least one block that processes a selected source signal and that responds to any of actual and potential degradation that source signal by (i) identifying from the identifier signals an alternate source signal, and (ii) processing that alternate source signal in lieu of the selected source signal,

wherein the field devices and blocks are coupled by any of a bus, a network and other communications media.

91. A control system according to claim 90, wherein the block executes within a field device.

92. A control system according to claim 90, wherein the field devices comprise any of a flow sensor, pressure sensor, temperature sensor, level sensor, valve, recorder, positioner, other sensor, and other actuator.

93. A control system according to claim 90, wherein at least one field device is self-validating.

94. A control system according to claim 93, wherein the self-validating field device generates the confidence signal to be representative of any of a status of a value represented by the corresponding source signal and a status of that self-validating field device.

95. A control system according to claim 90, comprising one or more registries that store the identifier signals.

96. A control system according to claim 95, comprising a plurality of distributed registries.

97. A control system according to claim 90, wherein the communications media is operable in accord with any of a Foundation Fieldbus standard, a Profibus standard, a DeviceNet™

standard, an InterBus™

standard and a Modbus®

standard.

98. A process control system comprising

a plurality of field devices, each generating a source signal representative of a control variable, an identifier signal identifying that control variable, and a confidence signal indicative of any of actual and potential degradation of that source signal,

wherein the field devices comprise any of flow sensors, pressure sensors, temperature sensors, level sensors, valves, recorders, positioners, other sensors and other actuators,

one or more registries that store the identifier signals,

at least one process control block that processes a selected source signal and that responds to any of actual and potential degradation that source signal by (i) identifying from the identifier signals an alternate source signal, and (ii) processing that alternate source signal in lieu of the selected source signal,

wherein the field devices, registries and control blocks are coupled by a network comprising one or more buses operable in accord with any of a Foundation Fieldbus standard, a Profibus standard, a DeviceNet™

standard, an InterBus™

standard and a Modbus®

standard.

99. A process control system according to claim 98, wherein any of a process control block and a registry are resident within a field device.

100. A process control system according to claim 98, wherein at least one field device is self-validating.

101. A process control system according to claim 98, wherein the self-validating field device generates the confidence signal to be representative of any of a status of a value represented by the corresponding source signal and a status of that self-validating field device.

102. A process control system according to claim 101, comprising plural registries that are distributed within the process control system.

103. A method of operating a control system comprising

generating, with each field device in a set of plural field devices, a source signal representative of a control variable, an identifier signal identifying that control variable, and a confidence signal indicative of any of actual and potential degradation of that source signal,

with at least one block, processing a selected source signal and responding to any of actual and potential degradation that source signal by (i) identifying from the identifier signals an alternate source signal, and (ii) processing that alternate source signal in lieu of the selected source signal,

wherein the field devices and blocks are coupled by any of a bus, a network and other communications media.

104. A method of operating a control system according to claim 103, comprising executing the block within a field device.

105. A method of operating a control system according to claim 103, wherein the field devices comprise any of a flow sensor, pressure sensor, temperature sensor, level sensor, valve, recorder, positioner, other sensor and other actuator.

106. A method of operating a control system according to claim 103, wherein at least one field device is self-validating.

107. A method of operating a control system according to claim 106, comprising generating, with the self-validating field device, the confidence signal to be representative of any of a status of a value represented by the corresponding source signal and a status of that self-validating field device.

108. A method of operating a control system according to claim 103, comprising storing the identifier signals in one or more registries.

109. A method of operating a control system according to claim 103, comprising storing the identifier signal in plural registries that are distributed about the control system.

110. A method of operating a control system according to claim 103, comprising transferring information among the field devices and blocks with a communications media operable in accord with any of a Foundation Fieldbus standard, a Profibus standard, a DeviceNet™

standard, an InterBus™

standard and a Modbus®

standard.

111. A method of operating a process control system comprising

generating, with each field device in a set of plural field devices, a source signal representative of a control variable, an identifier signal identifying that control variable, and a confidence signal indicative of any of actual and potential degradation of that source signal,

wherein the field devices comprise any of flow sensors, pressure sensors, temperature sensors, level sensors, valves, recorders, positioners, other sensors and other actuators,

one or more registries that store the identifier signals,

with at least one block, processing a selected source signal and responding to any of actual and potential degradation that source signal by (i) identifying from the identifier signals an alternate source signal, and (ii) processing that alternate source signal in lieu of the selected source signal,

transferring information among the field devices, registries and control blocks via a communications medium comprising one or more buses operable in accord with any of a Foundation Fieldbus standard, a Profibus standard, a DeviceNet™

standard, an InterBus™

standard and a Modbus®

standard.

112. A method of operating a process control system according to claim 111, comprising the step of executing a process control block within a field device.

113. A method of operating a process control system according to claim 111, wherein at least one field device is self-validating.

114. A method of operating a process control system according to claim 111, comprising generating, with the self-validating field device, the confidence signal to be representative of any of a status of a value represented by the corresponding source signal and a status of that self-validating field device.

115. A method of operating a process control system according to claim 114, comprising plural registries that are distributed within the process control system.