System and method for measuring system parameters and process variables using multiple sensors which are isolated by an intrinsically safe barrier

• US 6,885,949 B2
• Filed: 07/24/2002
• Issued: 04/26/2005
• Est. Priority Date: 07/24/2002
• Status: Expired due to Fees

• Current Assignee: Smar Research Corp.
• Original Assignee: Smar Research Corp.
• Inventors: Selli, Basilio
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): KIM, PAUL L
• Application Number:
  US10/202,345
• Publication Number:
  US 20040019440A1
• Time in Patent Office: 1,007 Days
• Field of Search: 700/79, 361 55- 57, 361/90, 361103-104, 702/57, 702/58
• US Class Current: 702/57
• CPC Class Codes: G01D 21/00 Measuring or testing not otherwise provided for
• CPC Class Codes: G01D 3/08 with provision for safeguarding the apparatus, e.g. against abnormal operation, against breakdown

Abstract

A system for measuring at least one parameter is provided. The system includes a control logic arrangement powered by a power source, and an intrinsically safe barrier operatively connected to the control logic arrangement, and also powered by the same power source. The intrinsically safe barrier is adapted to be operatively connected to at least one sensor which is also powered by the same power source. The sensor is configured to communicate data representing a parameter to the control logic arrangement via the intrinsically safe barrier. In one embodiment, the control logic arrangement, the intrinsically safe barrier and the sensor are galvonically isolated from external components and/or provided in one enclosure.

Claims

1. A system for measuring at least one of a parameter and variable, comprising:

a control logic arrangement powered by a power source; and

an intrinsically safe barrier operatively connected to the control logic arrangement, and powered by the power source, wherein the intrinsically safe barrier is adapted to be operatively connected to at least one sensor, wherein the sensor is powered by the power source, wherein the sensor is configured to communicate data representing the at least one of the parameter and the variable to the control logic arrangement via the intrinsically safe barrier, and wherein the power source is directly connected to the control logic arrangement and the intrinsically safe barrier, and

wherein the control logic arrangement includes;

a further transformer having a first terminal, a second terminal, a third terminal, and a fourth terminal, wherein the further transformer is electrically connected to the processor, and

a control interface electrically connected to the further transformer, wherein the control interface is configured to receive data representing the parameter from the control logic arrangement, and wherein the control interface transmits commands to the sensor via the control logic arrangement.

2. The system via the intrinsically safe barrier according to claim 1, further comprising a control interface powered by a further power source, wherein the control interface is configured to receive data representative of the parameter from the control logic arrangement.

3. The system according to claim 2, wherein the control interface transmits commands to the sensor via the control logic arrangement.

4. The system according to claim 3, wherein the control logic arrangement transmits the commands received from the control interface to the sensor via the intrinsically safe barrier.

5. The system according to claim 2, wherein the control interface transmits commands to the sensor via the intrinsically safe barrier.

6. The system according to claim 1, further comprising a control interface powered by a further power source, wherein the control interface is configured to receive data representing the parameter from the control logic arrangement, and wherein the control interface is configured to transmit commands directly to the sensor.

7. The system according to claim 1, wherein the control logic arrangement includes:

a transformer having a positive terminal and a negative terminal,

a capacitor having a first terminal and a second terminal,

a diode having a cathode and an anode, wherein the anode is electrically connected to the positive terminal of the transformer and the first terminal of the capacitor, and

a processor electrically connected to the cathode of the diode, and electrically connected to negative terminal of the transformer and the second terminal of the capacitor.

8. The system according to claim 1, wherein the data representing the process parameter received by the control logic arrangement from the sensor is digital data.

9. The system according to claim 1, wherein the data representing the process parameter received by the control logic arrangement from the sensor is transmitted using a communications protocol.

10. The system according to claim 1, wherein the intrinsically safe barrier electrically isolates the sensor from the control logic arrangement.

11. The system according to claim 10, wherein the intrinsically safe barrier limits the voltage differential over the sensor to a particular limit.

12. The system according to claim 11, wherein the particular limit is approximately 18 V.

13. The system according to claim 12, wherein the intrinsically safe barrier limits the amount of current provided to the sensor to a particular current amount.

14. The system according to claim 13, wherein the particular current amount is approximately 120 mA.

15. The system according to claim 1, wherein the intrinsically safe barrier includes:

a fuse,

a zener diode having a cathode and an anode, and

a resistor having a first terminal and a second terminal, wherein the first terminal of the resistor is electrically connected to the cathode of the zener diode and the fuse.

16. The system according to claim 1, further comprising an enclosure, wherein the control logic arrangement and the intrinsically safe barrier are located within the enclosure.

17. The system according to claim 1, wherein the control logic arrangement, the intrinsically safe barrier and the sensor are galvanically isolated from external components.

18. The system according to claim 1, wherein the intrinsically safe barrier is further adapted to be operatively connected to a second sensor, and wherein the second sensor is powered by the power source and configured to transmit data representing a further parameter via the intrinsically safe barrier to the control logic arrangement.

19. The system according to claim 18, wherein the data representative of the second parameter received by the control logic arrangement from the second sensor is digital data.

20. The system according to claim 18, wherein the data representative of the second parameter received by the control logic arrangement from the second sensor is transmitted using a communications protocol.

21. The system according to claim 20, wherein the communications protocol is a Fieldbus protocol.

22. A The system for measuring at least one of a parameter and variable, comprising:

a control logic arrangement powered by a power source; and

an intrinsically safe barrier operatively connected to the control logic arrangement, and powered by the power source, wherein the intrinsically safe barrier is adapted to be operatively connected to at least one sensor, wherein the sensor is powered by the power source, wherein the sensor is configured to communicate data representing the at least one of the parameter and the variable to the control logic arrangement via the intrinsically safe barrier, wherein the power source is directly connected to the control logic arrangement and the intrinsically safe barrier, and wherein the data representing the process parameter received by the control logic arrangement from the sensor is transmitted using a Fieldbus protocol.

23. A system for measuring at least one of a parameter and a variable, comprising:

a control logic arrangement; and

an intrinsically safe barrier operatively connected to the control logic arrangement, wherein the intrinsically safe barrier is adapted to be operatively connected to at least one sensor, wherein the sensor is configured to communicate data representing the at least one of the parameter and the variable to the control logic arrangement via the intrinsically safe barrier, and wherein the control logic arrangement, the intrinsically safe barrier and the sensor are galvanically isolated from external components.

24. The system according to claim 23, further comprising a control interface powered by a further power source, wherein the control interface is configured to receive data representative of the parameter from the control logic arrangement.

25. The system according to claim 24, wherein the control interface transmits commands to the sensor via the control logic arrangement.

26. The system according to claim 25, wherein the control logic arrangement transmits the commands received from the control interface to the sensor via the intrinsically safe barrier.

27. The system according to claim 24, wherein the control interface transmits commands to the sensor via the intrinsically safe barrier.

28. The system according to claim 23, further comprising a control interface powered by a further power source, wherein the control interface is configured to receive data representing the parameter from the control logic arrangement, and wherein the control interface is configured to transmit commands directly to the sensor.

29. The system according to claim 23, wherein the control logic arrangement includes:

a transformer having a positive terminal and a negative terminal,

a capacitor having a first terminal and a second terminal,

a diode having a cathode and an anode, wherein the anode is electrically connected to the positive terminal of the transformer and the first terminal of the capacitor, and

a processor electrically connected to the cathode of the diode, and electrically connected to negative terminal of the transformer and the second terminal of the capacitor.

30. The system according to claim 29, wherein the control logic arrangement further includes:

a further transformer having a first terminal, a second terminal, a third terminal, and a fourth terminal, wherein the further transformer is electrically connected to the processor, and

a control interface electrically connected to the further transformer, wherein the control interface is configured to receive data representing the parameter from the control logic arrangement, and wherein the control interface transmits commands to the sensor via the control logic arrangement.

31. The system according to claim 23, wherein the data representing the process parameter received by the control logic arrangement from the sensor is digital data.

32. The system according to claim 23, wherein the data representing the process parameter received by the control logic arrangement from the sensor is transmitted using a communications protocol.

33. The system according to claim 32, wherein the communications protocol is Fieldbus protocol.

34. The system according to claim 23, wherein the intrinsically safe barrier electrically isolates the sensor from the control logic arrangement.

35. The system according to claim 34, wherein the intrinsically safe barrier limits the voltage differential over the sensor to a particular limit.

36. The system according to claim 35, wherein the particular limit is approximately 18 V.

37. The system according to claim 36, wherein the intrinsically safe barrier limits the amount of current provided to the sensor to a particular current amount.

38. The system according to claim 37, wherein the particular current amount is approximately 120 mA.

39. The system according to claim 23, wherein the intrinsically safe barrier includes:

a fuse,

a zener diode having a cathode and an anode, and

a resistor having a first terminal and a second terminal, wherein the first terminal of the resistor is electrically connected to the cathode of the zener diode and the fuse.

40. The system according to claim 23, comprising an enclosure, wherein the control logic arrangement and the intrinsically safe barrier are located within the enclosure.

41. The system according to claim 23, wherein the power source is directly connected to the control logic arrangement and the intrinsically safe barrier, wherein the intrinsically safe barrier is further adapted to be operatively connected to a second sensor, and wherein the second sensor is powered by the power source and configured to transmit data representing a further parameter via the intrinsically safe barrier to the control logic arrangement.

42. The system according to claim 41, wherein the data representative of the second parameter received by the control logic arrangement from the second sensor is digital data.

43. The system according to claim 41, wherein the data representative of the second parameter received by the control logic arrangement from the second sensor is transmitted using a communications protocol.

44. The system according to claim 43, wherein the communications protocol is a Fieldbus protocol.

45. A measuring system for measuring at least one of a parameter and a variable, comprising:

an enclosure;

a control logic arrangement located within the enclosure; and

an intrinsically safe barrier operatively connected to the control logic arrangement and located within the enclosure, wherein the intrinsically safe barrier is adapted to be operatively connected to at least one sensor, wherein the sensor is configured to communicate data representing the at least one of the parameter and the variable to the control logic arrangement via the intrinsically safe barrier, and

wherein the control logic arrangement includes;

a further transformer having a first terminal, a second terminal, a third terminal, and a fourth terminal, wherein the further transformer is electrically connected to the processor, and

a control interface electrically connected to the further transformer, wherein the control interface is configured to receive data representing the parameter from the control logic arrangement, and wherein the control interface transmits commands to the sensor via the control logic arrangement.

46. The system according to claim 45, further comprising a control interface powered by a further power source, wherein the control interface is configured to receive data representative of the parameter from the control logic arrangement.

47. The system according to claim 46, wherein the control interface transmits commands to the sensor via the control logic arrangement.

48. The system according to claim 47, wherein the control logic arrangement transmits the commands received from the control interface to the sensor via the intrinsically safe barrier.

49. The system according to claim 46, wherein the control interface transmits commands to the sensor via the intrinsically safe barrier.

50. The system according to claim 48, further comprising a control interface powered by a further power source, wherein the control interface is configured to receive data representing the parameter from the control logic arrangement, and wherein the control interface is configured to transmit commands directly to the sensor.

51. The system according to claim 45, wherein the control logic arrangement includes:

a transformer having a positive terminal and a negative terminal,

a capacitor having a first terminal and a second terminal,

a diode having a cathode and an anode, wherein the anode is electrically connected to the positive terminal of the transformer and the first terminal of the capacitor, and

a processor electrically connected to the cathode of the diode, and electrically connected to negative terminal of the transformer and the second terminal of the capacitor.

52. The system according to claim 45, wherein the data representing the process parameter received by the control logic arrangement from the sensor is digital data.

53. The system according to claim 45, wherein the data representing the process parameter received by the control logic arrangement from the sensor is transmitted using a communications protocol.

54. The system according to claim 53, wherein the communications protocol is Fieldbus protocol.

55. The system according to claim 45, wherein the intrinsically safe barrier electrically isolates the sensor from the control logic arrangement.

56. The system according to claim 55, wherein the intrinsically safe barrier limits the voltage differential over the sensor to a particular limit.

57. The system according to claim 56, wherein the particular limit is approximately 18 V.

58. The system according to claim 57, wherein the intrinsically safe barrier limits the amount of current provided to the sensor to a particular current amount.

59. The system according to claim 58, wherein the particular current amount is approximately 120 mA.

60. The system according to claim 45, wherein the intrinsically safe barrier includes:

a fuse,

a zener diode having a cathode and an anode, and

a resistor having a first terminal and a second terminal, wherein the first terminal of the resistor is electrically connected to the cathode of the zener diode and the fuse.

61. The system according to claim 45, further comprising an enclosure, wherein the control logic arrangement and the intrinsically safe barrier are located within the enclosure.

62. The system according to claim 45, wherein the power source is directly connected to the control logic arrangement and the intrinsically safe barrier, wherein the intrinsically safe barrier is further adapted to be operatively connected to a second sensor, and wherein the second sensor is powered by the power source and configured to transmit data representing a further parameter via the intrinsically safe barrier to the control logic arrangement.

63. The system according to claim 62, wherein the data representative of the second parameter received by the control logic arrangement from the second sensor is digital data.

64. The system according to claim 62, wherein the data representative of the second parameter received by the control logic arrangement from the second sensor is transmitted using a communications protocol.

65. The system according to claim 64, wherein the communications protocol is a Fieldbus protocol.

66. The system according to claim 45, wherein the control logic arrangement, the intrinsically safe barrier and the sensor are galvanically isolated from external components.

67. A system for measuring at least one of a parameter and variable, comprising:

a control logic arrangement powered by a power source, wherein the control logic arrangement includes a control interface electrically isolated from the control logic arrangement and configured to receive data representing the parameter from the control logic arrangement; and

an intrinsically safe barrier operatively connected to the control logic arrangement, and powered by the power source, wherein the intrinsically safe barrier is adapted to be operatively connected to at least one sensor, wherein the sensor is powered by the power source, wherein the sensor is configured to communicate data representing the at least one of the parameter and the variable to the control logic arrangement via the intrinsically safe barrier, and wherein the power source is directly connected to the control logic arrangement and the intrinsically safe barrier.

68. The system of claim 67, wherein the control interface is electronically isolated from the control logic arrangement by a transformer.