MEASURING THE ACCURACY OF AN ENDPOINT CLOCK FROM A REMOTE DEVICE

• US 20100188938A1
• Filed: 01/29/2009
• Published: 07/29/2010
• Est. Priority Date: 01/29/2009
• Status: Active Grant

• Current Assignee: Itron, Inc.
• Original Assignee: Itron, Inc.
• Inventors: Johnson, Matthew, Cornwall, Mark
• Granted Patent: US 8,891,338 B2
• Time in Patent Office: Days
• US Class Current: 368/47
• CPC Class Codes: G01D 4/004 Remote reading of utility meters to a fixed location
• CPC Class Codes: G04C 11/04 over a line transmitting time signals over telephone networks H04M11/06 ; time setting G04C9/00
• 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

Packet formats and associated metering infrastructure for filtering meter reading data that is being transmitted by utility meters are disclosed. In one embodiment, a method is provided of measuring the accuracy of an endpoint clock, such as a utility meter clock, from a remote device configured to capture transmissions that originate from the utility meter. Generally, the method includes synchronizing the time maintained by the utility meter with the time maintained by the remote device. The method receives and decodes a packet that includes a time stamp provided by the utility meter. Then, the method calculates the extent of the inaccuracy of the time stamp in the received packet and determines whether the extent of the inaccuracy satisfies a predetermined threshold.

Claims

1. A method of measuring the accuracy of a utility meter clock from a remote device configured to capture transmissions that originate from the utility meter, the method comprising:

synchronizing the time maintained by the utility meter with the time maintained by the remote device;

receiving and decoding a packet that includes a time stamp provided by the utility meter; and

calculating the extent of the inaccuracy of the time stamp in the received packet and determining whether the extent of the inaccuracy satisfies a predetermined threshold.

2. The method as recited in claim 1, further comprising if a determination is made that the extent of the inaccuracy satisfies a predetermined threshold, causing a software update to be installed on the utility meter that compensates for the inaccuracy.

3. The method as recited in claim 1, wherein the time stamp records the time elapsed by the utility meter clock since the most recent synchronization with the remote device.

4. The method as recited in claim 1, wherein determining whether the extent of the inaccuracy satisfies a predetermined threshold includes normalizing inaccuracies reflected in a plurality of received packets.

5. The method as recited in claim 1, wherein determining whether the extent of the inaccuracy satisfies a predetermined threshold includes identifying the percentage of the inaccuracy relative to the most recent synchronization.

6. A collector configured to assess the accuracy of a utility meter clock having instructions that, when executed by a processor, cause the collector to:

receive and decode a packet that includes a time stamp provided by the utility meter;

perform a comparison between the time stamp in the received packet with the time maintained by the collector; and

based on the comparison, calculating the extent of the inaccuracy of the time stamp in the received packet.

7. The collector as recited in claim 6, further configured to:

cause a host server to determine whether the extent of the inaccuracy of the time stamp is indicative of an error condition; and

if the host server determines that the inaccuracy is indicative of an error condition, the collector is further configured to obtain a software update from the host server and cause the software update to be installed on the utility meter to correct the inaccuracy.

8. The collector as recited in claim 6, wherein the time maintained by the utility meter is synchronized with the time of the collector on a periodic basis and the time stamp in the packet represents the elapsed time since the most recent synchronization.