Gauging system having wireless capability

• US 8,264,373 B2
• Filed: 01/04/2008
• Issued: 09/11/2012
• Est. Priority Date: 01/04/2008
• Status: Active Grant

• Current Assignee: Rosemount Tank Radar AB (Emerson Electric Company)
• Original Assignee: Rosemount Tank Radar AB (Emerson Electric Company)
• Inventors: Hägg, Lennart
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): VU, TOAN T
• Application Number:
  US11/969,345
• Publication Number:
  US 20090174570A1
• Time in Patent Office: 1,712 Days
• Field of Search: 340/870.07
• US Class Current: 340/870.07
• CPC Class Codes: G08C 17/02 using a radio link

Abstract

The present invention relates to a gauging system, comprising a gauge configured to sense a process variable and to provide process data representative of the process variable, a processing unit connected to the gauge, the processing unit comprising power supply circuitry configured to receive power from a remote external power source and to provide regulated power, and first circuitry configured to receive process data from the gauge and to superimpose the process data onto the regulated power forming a power signal, and a wireless communication unit electrically connected to the processing unit by means of a two-wire control loop, the wireless communication unit comprising second circuitry configured to receive the power signal and to separate the process data from the regulated power, an antenna, and radio frequency (RF) communication circuitry being powered by means of the regulated power from the second circuitry, configured to receive process data from the second circuitry, and to transmit RF signals representative of the process data using the antenna, wherein the power signal is capable of delivering enough regulated power to the wireless communication unit for allowing transmission of RF signals at any given moment.

Claims

1. A gauging system, comprising:

a gauge configured to sense a process variable and to provide process data representative of the process variable;

a processing unit connected to the gauge, the processing unit comprising;

power supply circuitry configured to receive power from a remote external power source other than a two-wire control loop and to provide regulated power; and

first circuitry configured to receive process data from the gauge and to superimpose the process data onto the regulated power forming a power signal; and

a wireless communication unit electrically connected to the processing unit by means of a two-wire control interface, the wireless communication unit comprising;

second circuitry configured to receive the power signal and to separate the process data from the regulated power;

an antenna; and

radio frequency (RF) communication circuitry being powered by means of the regulated power from the second circuitry, configured to receive process data from the second circuitry, and to transmit RF signals representative of the process data using the antenna.

2. The gauging system of claim 1, wherein the regulated power is provided in an intrinsically safe manner.

3. The gauging system of claim 1, wherein the power signal is provided in an intrinsically safe manner.

4. The gauging system of claim 1, wherein the remote external power source is configured to deliver at least 100 Volts to the power supply circuitry.

5. The gauging system of claim 1, wherein the process data is digitally superimposed on the regulated power.

6. The gauging system of claim 1, wherein the first circuitry comprises a digital HART modem, powered by said power supply circuitry and programmed to provide an output current sufficient to power the wireless communication unit.

7. The gauging system of claim 1, wherein said output power is sufficient to activate said wireless communication unit at any given moment.

8. The gauging system of claim 1, wherein the power supply circuitry provides at least 40 mW by means of the power signal to the wireless communication unit at a moment of transmission of RF signals.

9. The gauging system of claim 1, wherein the wireless communication unit is configured in accordance to a self-organizing mesh network.

10. The gauging system of claim 9, wherein the self-organizing mesh network is configured according to a time synchronized mesh protocol (TSMP).

11. The gauging system of claim 1, wherein the RF circuitry is configured for digital communication.

12. The gauging system of claim 1, wherein the RF circuitry is configured for analog communication.

13. The gauging system of claim 1, wherein the electrical connection between the processing unit and the wireless communication unit comprises a third wire.

14. The gauging system of claim 1, wherein the gauge is a microwave-based level gauge configured to sense a level of a product in a tank through reflection of microwave energy.

15. The gauging system of claim 1, wherein the gauge is a temperature gaug configured to sense a temperature of a product in a tank.

16. The gauging system of claim 1, wherein the gauge is a Coriolis flow meter configured to sense a direct measurement of mass flow of a product.

17. The gauging system of claim 1, wherein the gauge and the processing unit are physically separated.

18. The gauging system of claim 1, wherein the gauge and the processing unit are physically combined.

19. A method for providing power to a wireless communication unit electrically connected to a processing unit by means of a two-wire control interface, wherein the method comprises:

receiving a sensed process variable from a gauge connected to the processing unit, thereby forming process data representative of the process variable;

providing regulated power based on power received from a remote external power source other than a two-wire control loop;

superimposing the process data onto the regulated power, thereby forming a power signal;

providing the power signal to the wireless communication unit,

separating the process data from the regulated power;

providing the regulated power to radio frequency (RF) communication circuitry comprised in the wireless communication unit;

providing the separated process data to the RF communication circuitry; and

transmitting RF signals representative of the process data by means of an antenna connected to the RF circuitry.

20. Method of claim 19, further comprising the step of providing the regulated power in an intrinsically safe manner.

21. A gauging system, comprising:

power supply circuitry configured to receive power from an external power source other than a two-wire control loop,

a gauge, powered by said power supply circuitry, and configured to sense a process variable and to provide process data representative of the process variable;

a two-wire control interface, and

a wireless communication unit,

wherein said two-wire control interface is used to power said wireless communication unit and to communicate said process data to said wireless communication unit.

22. The gauging system according to claim 21, wherein said two-wire control interface comprises a HART modern powered by said power supply circuitry and programmed to provide an output current sufficient to power the wireless communication unit.

23. The gauging system according to claim 21, wherein said output power is sufficient to activate said wireless communication unit at any given moment.

24. The gauging system of claim 21, wherein the remote external power source is configured to deliver at least 100 Volts to the power supply circuitry.

25. The gauging system of claim 21, wherein said two-wire control interface is connected only to said wireless communication unit.

26. The gauging system of claim 21, wherein the process data is digitally superimposed on a power signal.

27. The gauging system of claim 21, wherein the two-wire interface provides at least 40 mW power to the wireless communication unit at a moment of wireless transmission.