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

• US 20040019440A1
• Filed: 07/24/2002
• Published: 01/29/2004
• Est. Priority Date: 07/24/2002
• Status: Active Grant

• Current Assignee: Smar Research Corp.
• Original Assignee: Smar Research Corp.
• Inventors: Selli, Basilio
• Granted Patent: US 6,885,949 B2
• Time in Patent Office: Days
• 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.

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 7, 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 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.

9. 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.

10. 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.

11. The system according to claim 10, wherein the communications protocol is Fieldbus protocol.

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

13. The system according to claim 12, wherein the intrinsically safe barrier limits the voltage differential over the sensor to a particular limit.

14. The system according to claim 13, wherein the particular limit is approximately 18 V.

15. The system according to claim 14, wherein the intrinsically safe barrier limits the amount of current provided to the sensor to a particular current amount.

16. The system according to claim 15, wherein the particular current amount is approximately 120 mA.

17. 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.

18. 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.

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

20. 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.

21. The system according to claim 20, wherein the data representative of the second parameter received by the control logic arrangement from the second sensor is digital data.

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

23. The system according to claim 22, wherein the communications protocol is a Fieldbus protocol.

24. 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 galvonically isolated from external components.

25. The system according to claim 24, 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.

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

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

28. The system according to claim 25, wherein the control interface transmits commands to the sensor via the intrinsically safe barrier.

29. The system according to claim 24, 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.

30. The system according to claim 24, 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.

31. The system according to claim 30, 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 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.

32. The system according to claim 24, wherein the data representing the process parameter received by the control logic arrangement from the sensor is digital data.

33. The system according to claim 24, wherein the data representing the process parameter received by the control logic arrangement from the sensor is transmitted using a communications protocol.

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

35. The system according to claim 24, wherein the intrinsically safe barrier electrically isolates the sensor from the control logic arrangement.

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

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

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

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

40. The system according to claim 24, 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.

41. The system according to claim 24, further comprising an enclosure, wherein the control logic arrangement and the intrinsically safe barrier are located within the enclosure.

42. The system according to claim 24, 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.

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

44. The system according to claim 42, wherein the data representative of the second parameter received by the control logic arrangement from the second sensor is transmitted using a communications protocol.

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

46. 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, and 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.

47. The system according to claim 46, 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.

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

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

50. The system according to claim 47, wherein the control interface transmits commands to the sensor via the intrinsically safe barrier.

51. The system according to claim 46, 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.

52. The system according to claim 46, 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.

53. The system according to claim 52, 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 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.

54. The system according to claim 46, wherein the data representing the process parameter received by the control logic arrangement from the sensor is digital data.

55. The system according to claim 46, wherein the data representing the process parameter received by the control logic arrangement from the sensor is transmitted using a communications protocol.

56. The system according to claim 55, wherein the communications protocol is Fieldbus protocol.

57. The system according to claim 46, wherein the intrinsically safe barrier electrically isolates the sensor from the control logic arrangement.

58. The system according to claim 57, wherein the intrinsically safe barrier limits the voltage differential over the sensor to a particular limit.

59. The system according to claim 58, wherein the particular limit is approximately 18 V.

60. The system according to claim 59, wherein the intrinsically safe barrier limits the amount of current provided to the sensor to a particular current amount.

61. The system according to claim 60, wherein the particular current amount is approximately 120 mA.

62. The system according to claim 46, 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.

63. The system according to claim 46, further comprising an enclosure, wherein the control logic arrangement and the intrinsically safe barrier are located within the enclosure.

64. The system according to claim 46, 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.

65. The system according to claim 64, wherein the data representative of the second parameter received by the control logic arrangement from the second sensor is digital data.

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

67. The system according to claim 66, wherein the communications protocol is a Fieldbus protocol.

68. The system according to claim 46, wherein the control logic arrangement, the intrinsically safe barrier and the sensor are galvonically isolated from external components.