LOW POWER TELEMETRY SYSTEM AND METHOD

• US 20110215831A1
• Filed: 05/17/2011
• Published: 09/08/2011
• Est. Priority Date: 05/30/2003
• Status: Active Grant

• Current Assignee: General Dynamics Advanced Information Systems Incorporated (General Dynamics Corporation)
• Original Assignee: General Dynamics Advanced Information Systems Incorporated (General Dynamics Corporation)
• Inventors: Holt, Michael D.
• Granted Patent: US 8,537,849 B2
• Time in Patent Office: Days
• US Class Current: 326/30
• CPC Class Codes: H04Q 2209/30 using a wired architecture
• CPC Class Codes: H04Q 2209/756 where the polling of the sub-stations is cyclic, e.g. round-robin
• 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

A telemetry system is described in which a plurality of channels are coupled to a bus. A control subsystem controls the channels so that one of the channels presents to the bus during its designated time period a channel characteristic. The control subsystem interrogates in the analog domain each of the channels during its designated time period, and forms a signal representative of the channel characteristic. The control subsystem may combine one or more of the signals into a digital packet, and transmit the same over a network. Each channel in the telemetry system can include a sample-and-hold circuit, a variable resistor circuit, and a control element. The sample-and-hold circuit is configured to hold a sample of a signal. The variable resistor circuit is configured to present a variable impedance to one or more signal lines during a time period designated for the channel an impedance representative of the sample held by the sample-and-hold circuit. The control element is configured to control the variable resistor circuit to present to the one or more signal lines an open circuit equivalent impedance during times other than the time period designated for the channel. In some implementations, the channel also includes a switch which decouples the sample-and-hold circuit from the variable resistor circuit during times other than the time period designated for the channel. In some implementations, the control element is a programmable control element that is programmable with a unique channel identifier, and may include a timing element which is updated responsive to a control signal. The programmable control element determines that the designated time period for the channel is occurring or will occur based on a comparison of the contents of the timing element with the unique channel identifier. The control element can be a zero power control element.

Claims

1. A channel in a telemetry system, comprising:

a sample-and-hold circuit for holding a sample of a signal;

a variable resistor circuit for presenting a variable impedance to one or more signal lines during a time period designated for the channel an impedance representative of the sample held by the sample-and-hold circuit; and

a control element for controlling the variable resistor circuit to present to the one or more signal lines an open circuit equivalent impedance during times other than the time period designated for the channel.

2. The channel of claim 1, further comprising:

a switch which decouples the sample-and-hold circuit from the variable resistor circuit during times other than the time period designated for the channel.

3. The channel of claim 1, wherein the control element is a programmable control element.

4. The channel of claim 3, wherein the control element is programmable with a unique channel identifier.

5. The channel of claim 4, wherein the control element includes a timing element which is updated responsive to a control signal.

6. The channel of claim 5, wherein the control element determines that the designated time period for the channel is occurring or will occur based on a comparison of the contents of the timing element with the unique channel identifier.

7. The channel of claim 6, wherein the control element is a zero power control element.

8. A channel in a telemetry system, comprising:

a sample-and-hold circuit configured to hold a sample of a signal;

a variable resistor circuit configured to present a variable impedance to one or more signal lines during a time period designated for the channel an impedance representative of the sample held by the sample-and-hold circuit; and

a programmable control element configured to control the variable resistor circuit to present to the one or more signal lines an open circuit equivalent impedance during times other than the time period designated for the channel.

9. The channel of claim 8, further comprising:

a switch configured to decomple the sample-and-hold circuit from the variable resistor circuit during times other than the time period designated for the channel.

10. The channel of claim 8, wherein the programmable control element is programmable with a unique channel identifier.

11. The channel of claim 10, wherein the programmable control element includes a timing element which is configured to be updated responsive to a control signal.

12. The channel of claim 11, wherein the programmable control element that is configured to determine that the designated time period for the channel is occurring or will occur based on a comparison of the contents of the timing element with the unique channel identifier.

13. The channel of claim 12, wherein the programmable control element is a zero power programmable control element.

14. A channel in a telemetry system, comprising:

a sample-and-hold circuit for holding a sample of a signal;

a variable resistor circuit for presenting a variable impedance to one or more signal lines during a time period designated for the channel an impedance representative of the sample held by the sample-and-hold circuit;

a programmable control element for controlling the variable resistor circuit to present to the one or more signal lines an open circuit equivalent impedance during times other than the time period designated for the channel; and

a switch which decouples the sample-and-hold circuit from the variable resistor circuit during times other than the time period designated for the channel.

15. The channel of claim 14, wherein the programmable control element is programmable with a unique channel identifier.

16. The channel of claim 15, wherein the programmable control element includes a timing element which is updated responsive to a control signal.

17. The channel of claim 16, wherein the programmable control element determines that the designated time period for the channel is occurring or will occur based on a comparison of the contents of the timing element with the unique channel identifier.

18. The channel of claim 17, wherein the programmable control element is a zero power programmable control element.