Time synchronization of portable devices

• US 8,301,931 B2
• Filed: 05/22/2009
• Issued: 10/30/2012
• Est. Priority Date: 05/22/2009
• Status: Expired due to Fees

• Current Assignee: Itron, Inc.
• Original Assignee: Itron, Inc.
• Inventors: Johnson, Matthew
• Primary Examiner(s): MISIURA, BRIAN THOMAS
• Application Number:
  US12/470,694
• Publication Number:
  US 20100299457A1
• Time in Patent Office: 1,257 Days
• Field of Search: 710/13, 702/62, 713400-401, 34087001-87003
• US Class Current: 713/400
• CPC Class Codes: G01D 4/002 Remote reading of utility meters
• CPC Class Codes: G06F 1/10 Distribution of clock signals , e.g. skew
• CPC Class Codes: G06F 1/12 Synchronisation of different clock signals provided by a plurality of clock generators
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04L 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54
• CPC Class Codes: H04L 67/5683 Storage of data provided by user terminals, i.e. reverse caching
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y04S 20/30 Smart metering, e.g. specially adapted for remote reading

Abstract

A portable time transfer device is provided to transfer accurate date/time to reader devices and, thus, the reader devices do not have to be connected to a source of accurate time. A host computing system is configured to synchronize the portable time transfer device to a network, GPS, or other source of precise (accurate) time. Once the portable time transfer device is synchronized to the accurate date/time by the host computing system, the portable time transfer device is ready to be used by reader devices or any other devices (e.g., laptops, etc.) which need to maintain accurate time regardless of the connectivity to a network or GPS.

Claims

1. A method for transferring a standard for accurate time within a meter reading system that includes a computing system, a reader device, and a time transfer device, wherein the time transfer device is accessible by the computing system and the reader device, the method comprising:

detecting the time transfer device that is connected to the computing system;

obtaining accurate time from a time source;

accessing a clock of the time transfer device to read a device time of the time transfer device;

downloading data stored in the time transfer device; and

synchronizing the clock of the time transfer device to the obtained accurate time.

2. The method of claim 1, wherein the reader device synchronizes an internal clock to the time read from the clock of the time transfer device.

3. The method of claim 1, wherein the reader device collects data, times tamps the collected data and stores the time stamped data in the time transfer device.

4. The method of claim 3, wherein the time transfer device is connected to the computing system in order to transfer the stored data.

5. The method of claim 1, wherein the data stored in the time transfer device is downloaded into the computing system if a difference between the device time and the accurate time is within a tolerance range.

6. An apparatus for transferring a standard time to reader devices in a meter reading system, the apparatus comprising a clock and a memory, the apparatus operable to:

receive, from a host computing system, a first standard time into the clock, wherein the clock is synchronized to the received first standard time;

connect to a reader device for transferring the first standard time, wherein, upon connection, the reader device is synchronized to the first standard time;

receive data collected by the reader device, the received data being stored in the memory;

connect to the host computing system for downloading the data stored in the memory; and

receive, from the host computing system, a second standard time into the clock, wherein the clock is re-synchronized to the second standard time.

7. The apparatus of claim 6, wherein the host computing system obtains the first standard and the second standard times from a source of accurate time.

8. The apparatus of claim 6, wherein the host computing system downloads the data from the memory after verifying that a device time of the clock is within a predefined error range.

9. The apparatus of claim 7, wherein the source of accurate time is a network, or Global Positioning System.

10. The apparatus of claim 6, wherein the reader device comprises a real clock that is synchronized to the first standard time.

11. A method for transferring accurate time from a time transfer device to a reader device, wherein the time transfer device is accessible by the reader device, the method comprising:

detecting the time transfer device that is connected to the reader device at the time of initialization of the reader device;

accessing a clock of the time transfer device to read a device time of the time transfer device;

synchronizing the clock of the reader device to the device time of the time transfer device;

collecting meter reading data from meters; and

storing in the time transfer device the collected meter reading data with timestamps based on the clock of the reader device;

wherein, before the initialization of the reader device, the clock of the time transfer device was synchronized to the accurate time by a computing device that has connectivity to a source of the accurate time.

12. The method of claim 11, wherein, when the time transfer device is connected to the computing device for downloading the stored meter reading data, the computing device synchronizes the time transfer device to the source of accurate time.

13. The method of claim 11, wherein the initialization is triggered when power is provided to the reader device.