Performing metering using pulse counting

• US 8,136,409 B2
• Filed: 05/28/2010
• Issued: 03/20/2012
• Est. Priority Date: 05/28/2010
• Status: Active Grant

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Pflum, Marty Lynn
• Primary Examiner(s): Thompson, Jewel V
• Application Number:
  US12/790,466
• Publication Number:
  US 20110290036A1
• Time in Patent Office: 662 Days
• Field of Search: 734/62, 734/64, 738/610.8
• US Class Current: 73/861.08
• CPC Class Codes: G01D 4/02 Details
• CPC Class Codes: G01F 15/063 using electrical means
• CPC Class Codes: G01R 11/16 Adaptations of counters to electricity meters
• CPC Class Codes: H03K 3/356121 with synchronous operation H03K3/35613, H03K3/356147 take precedence

Abstract

An apparatus can include a first detector to receive a first signal from a first switch configured to open and close based on position of a metering wheel associated with a flow line. The apparatus can further include a first counter to count within a first range based on a change in a state of the first signal. Using this information, the apparatus can determine usage and direction of, e.g., a fluid or liquid flowing along the flow line.

Claims

1. An apparatus comprising:

a first detector to receive a first signal from a first switch configured to open and close based on position of a metering wheel associated with a flow line;

a second detector to receive a second signal from a second switch configured to open and close based on the metering wheel position;

a first counter to count within a first predetermined range based on a change in a state of at least one of the first and second signals that indicates movement of the metering wheel in a first direction; and

a second counter to count within a second predetermined range based on a change in the state that indicates movement of the metering wheel in a second direction, wherein usage and direction of a fluid or gas flowing along the flow line is based on counts of the first and second counters.

2. The apparatus of claim 1, wherein the first counter is programmed to count in a first direction when the flow direction is forwards and to count in an opposite direction when the flow direction is backwards.

3. The apparatus of claim 2, wherein the second counter is to count only when the flow direction is backwards.

4. The apparatus of claim 1, further comprising a wake circuit to cause a controller to wake up when at least one of the first and second counters reaches an end of the corresponding predetermined range.

5. The apparatus of claim 4, wherein the controller increments a stored value to update a consumption level of the fluid or gas when the first counter reaches the first predetermined range end and to reset the first counter to a beginning of the first predetermined range, and thereafter enters a sleep state.

6. The apparatus of claim 1, further comprising a first pull up circuit coupled to the first detector, the first pull up circuit controllable to provide a pull up impedance between a first voltage node and the first detector, wherein the first pull up circuit can be disabled to reduce power consumption of the apparatus.

7. The apparatus of claim 6, wherein a value of the pull up impedance is set based on a calibration in which a maximum pull up impedance is tested, and then a line coupled to the first detector is discharged and charged using a selected pull up impedance and a current is determined, and wherein the discharging, charging and current determination is sequentially performed until a lowest strength pull up impedance that provides a predetermined current level within a predetermined time period is selected.

8. The apparatus of claim 1, further comprising debounce circuitry coupled between the first detector and the first counter, wherein the debounce circuitry includes a programmable integrator to enable a level detection of the first signal if a predetermined number of samples of the first signal at a first level have occurred during a sample period.

9. The apparatus of claim 1, wherein the apparatus comprises an integrated circuit having a first die including the first and second detectors and the first and second counters, and a second die including a radio circuit to couple with an antenna to wirelessly communicate information received from the first die.

10. The apparatus of claim 1, wherein the second counter is disabled when the apparatus is in a single or dual mode and enabled when the apparatus is in a quadrature mode.

11. A method comprising:

receiving a first signal in a metering circuit from a first switch associated with a metering wheel associated with a flow line;

determining, in the metering circuit, whether the first signal has transitioned from a first state to a second state; and

updating a first count of the metering circuit within a first predetermined range responsive to a first control signal received from a state machine for an operation mode of the metering circuit, the first control signal based at least in part on the transition.

12. The method of claim 11, further comprising:

sending a wake up signal to a control circuit to wake the control circuit when the first count has reached an end of the first predetermined range.

13. The method of claim 12, further comprising updating a stored value to reflect that the first count has reached the end of the first predetermined range and resetting the first count to a beginning of the first predetermined range, and thereafter disabling the control circuit.

14. The method of claim 11, further comprising:

receiving a second signal in the metering circuit from a second switch associated with the metering wheel;

determining, in the metering circuit, whether the second signal has transitioned from a first state to a second state; and

updating the first count in a first direction if the transition in at least one of the first and second signals indicates clockwise movement of the metering wheel, and otherwise not updating the first count if the transition indicates counter-clockwise movement of the metering wheel.

15. The method of claim 14, further comprising updating a second count if the transition indicates counter-clockwise movement of the metering wheel.

16. The method of claim 11, further comprising outputting a first control signal from a programmable integrator coupled to the first switch if a predetermined number of samples of the first signal at a first level have occurred during a sample period.

17. The method of claim 11, further comprising sending a first disable signal from the state machine to a first pull up circuit coupled to a first detector that receives the first signal based on a state of the first signal, the first pull up circuit controllable to provide a pull up impedance between a first voltage node and the first detector when not disabled by the first disable signal.

18. A system comprising:

a metering circuit including a first detector to receive a first signal from a first switch configured to open and close based on position of a metering wheel associated with a flow line and to output a first detection signal, a logic unit to receive the first detection signal, to generate a first control signal based on a state of the first detection signal, and to provide the first control signal to a first counter to update a first count within a first predetermined range responsive to the first control signal, and a controller to update a metering count when the first counter reaches an end of the first predetermined range, the metering count corresponding to an amount of fluid or gas that has flowed through the flow line; and

a radio circuit coupled to the metering circuit, the radio circuit to communicate control information to the metering circuit and to receive metering information from the metering circuit, the metering information including the metering count, wherein the radio circuit is to couple to an antenna to enable wireless transmission of at least some of the metering information.

19. The system of claim 18, wherein the metering circuit further includes a second detector to receive a second signal from a second switch configured to open and close based on the metering wheel position and to output a second detection signal, and a second counter, wherein the second counter counts within a second predetermined range responsive to a second control signal generated by the logic unit based on a change in state of at least one of the first and second detection signals.

20. The system of claim 19, wherein the metering circuit further includes:

a third counter to be incremented on a first edge of the first control signal and to be decremented on a first edge of the second control signal;

a fourth counter to be incremented on a second edge of the first control signal and to be decremented on a second edge of the second control signal; and

a third detector to detect flutter or an error in the first or second switch based on a count of at least one of the third and fourth counters.

21. The system of claim 18, wherein the system comprises a meter device including a first semiconductor die having the metering circuit and a second semiconductor die having the radio circuit.