Battery-powered level gauge system adapted for wireless communication

• US 8,970,395 B2
• Filed: 06/29/2012
• Issued: 03/03/2015
• Est. Priority Date: 06/29/2012
• Status: Active Grant

• Current Assignee: Rosemount Tank Radar AB (Emerson Electric Company)
• Original Assignee: Rosemount Tank Radar AB (Emerson Electric Company)
• Inventors: Nilsson, Leif, Nyberg, Hkan, Delin, Hkan
• Primary Examiner(s): MCNALLY, KERRI L
• Application Number:
  US13/537,513
• Publication Number:
  US 20140002274A1
• Time in Patent Office: 977 Days
• Field of Search: 340/870.02
• US Class Current: 340/870.02
• CPC Class Codes: G01F 23/284 Electromagnetic waves
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• CPC Class Codes: H04Q 2209/883 where the sensing device enters an active or inactive mode
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

The present invention relates to a method comprising providing an activation signal from a wireless communication unit to a measurement unit to switch the measurement unit from its inactive state to its active state; providing a measurement request signal to the measurement unit to request measurement of a filling level of a product in a tank; and thereafter switching the wireless communication unit from its active state to its inactive state. The measurement unit measures the filling level and provides a measurement ready signal to the wireless communication unit; the wireless communication unit is switched from its inactive state to its active state in response to the measurement ready signal received from the measurement unit; the wireless communication unit retrieves the value indicative of the filling level from the measurement unit; and wirelessly transmits the value indicative of the filling level to the remote device.

Claims

1. A method of providing a value indicative of a filling level of a product contained in a tank to a remote device using a battery-powered level gauge system comprising a measurement unit and a wireless communication unit, each being controllable between an active state and an inactive state with a lower power consumption than said active state, the method comprising the steps of:

providing an activation signal from said wireless communication unit to said measurement unit to switch said measurement unit from its inactive state to its active state;

providing a measurement request signal from said wireless communication unit to said measurement unit to request measurement of said filling level;

switching said wireless communication unit from its active state to its inactive state after having provided said measurement request signal to said measurement unit;

measuring said filling level by said measurement unit;

providing, after having measured said filling level, a measurement ready signal from said measurement unit to said wireless communication unit;

switching said wireless communication unit from its inactive state to its active state in response to said measurement ready signal received from said measurement unit at said wireless communication unit;

retrieving said value indicative of said filling level from said measurement unit to said wireless communication unit; and

wirelessly transmitting said value indicative of said filling level to said remote device.

2. The method according to claim 1,

wherein said step of wirelessly transmitting said value indicative of said filling level to said remote device takes place during a time slot for wireless communication, consecutive time slots for wireless communication being separated by an interval time, and

wherein said wireless communication unit controls said measurement unit to measure said filling level during a measurement time period being in a latter half of said interval time.

3. The method according to claim 2, wherein said measurement time period is in a final tenth of said interval time.

4. The method according to claim 2, wherein said wireless communication unit provides said activation signal and said measurement request signal to said measurement unit during said latter half of said interval time.

5. The method according to claim 2, wherein a timing of said measurement time period is encoded by said measurement request signal.

6. The method according to claim 1, further comprising the step of:

providing a deactivation signal from said wireless communication unit to said measurement unit after having retrieved said value indicative of said filling level, to switch said measurement unit from its active state to its inactive state.

7. The method according to claim 1, wherein said method, after the step of providing said measurement request signal from said wireless communication unit to said measurement unit, further comprises the step of:

controlling a timer to switch said wireless communication unit from its inactive state to its active state after a predefined time-out period being longer than an expected time period until receiving said measurement ready signal from said measurement unit.

8. The method according to claim 1, wherein said filling level is measured by transmitting an electromagnetic transmit signal towards a surface of said product contained in the tank, receiving an electromagnetic reflection signal resulting from reflection of said electromagnetic transmit signal at said surface, and determining said filling level based on said electromagnetic reflection signal.

9. A battery-powered level gauge system for providing a value indicative of a filling level of a product contained in a tank to a remote device using wireless communication, said battery-powered level gauge system comprising:

a measurement unit configured to measure said filling level, said measurement unit being controllable between an active state and an inactive state with a lower power consumption than said active state;

a wireless communication unit connected to said measurement unit for retrieving said value indicative of said filling level from said measurement unit and wirelessly transmitting said value indicative of said filling level to said remote device, said wireless communication unit being controllable between an active state and an inactive state with a lower power consumption than said active state; and

a local energy store connected to said measurement unit and said wireless communication unit for supplying energy sufficient for operation of said measurement unit and said wireless communication unit,

wherein said measurement unit is configured to;

measure said filling level in response to a measurement request signal from said wireless communication unit; and

provide, after having measured said filling level, a measurement ready signal to said wireless communication unit; and

wherein said wireless communication unit is configured to;

provide an activation signal to said measurement unit to switch said measurement unit from its inactive state to its active state;

provide a measurement request signal to said measurement unit to request measurement of said filling level;

switch said wireless communication unit from its active state to its inactive state after having provided said measurement request signal to said measurement unit;

switch said wireless communication unit from its inactive state to its active state in response to a measurement ready signal received from said measurement unit;

retrieve said value indicative of said filling level from said measurement unit; and

wirelessly transmit said value indicative of said filling level to said remote device.

10. The battery-powered level gauge system according to claim 9, wherein:

said measurement unit comprises a first output for providing said measurement ready signal, and a second output, separate from said first output, for providing said value indicative of said filling level to said wireless communication unit; and

said wireless communication unit comprises a first input connected to said first output of the measurement unit for receiving said measurement ready signal, and a second input, separate from said first input, connected to said second output of the measurement unit for receiving said value indicative of said filling level.

11. The battery-powered level gauge system according to claim 9, wherein said wireless communication unit is further configured to provide a deactivation signal to said measurement unit after having retrieved said value indicative of said filling level, to switch said measurement unit from its active state to its inactive state.

12. The battery-powered level gauge system according to claim 9, wherein:

said wireless communication unit further comprises a timer; and

said wireless communication unit is further configured to control said timer to switch said wireless communication unit from its inactive state to its active state after a predefined time-out period being longer than an expected time period until receiving said measurement ready signal from said measurement unit.

13. The battery-powered level gauge system according to claim 9,

wherein said wireless communication unit is configured to wirelessly transmit said value indicative of said filling level to said remote device during a time slot for wireless communication, consecutive time slots for wireless communication being separated by an interval time, and

wherein said wireless communication unit configured to control said measurement unit to measure said filling level during a measurement time period being in a latter half of said interval time.

14. The battery-powered level gauge system according to claim 9, wherein said wireless communication unit is configured to wirelessly transmit said value indicative of said filling level to said remote device only during fixed time slots.

15. The battery-powered level gauge system according to claim 9, wherein said measurement unit comprises:

a transceiver for generating, transmitting and receiving electromagnetic signals;

a propagation device connected to said transceiver for propagating an electromagnetic transmit signal from said transceiver towards a surface of said product contained in said tank and to return to said transceiver an electromagnetic return signal resulting from reflection at said surface of said electromagnetic transmit signal; and

processing circuitry for determining said filling level based on said electromagnetic return signal.