Power management system for a field device on a wireless network

• US 8,103,316 B2
• Filed: 07/25/2007
• Issued: 01/24/2012
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Chakraborty, Swapan, Orth, Kelly M.
• Primary Examiner(s): Eng, George
• Assistant Examiner(s): Torres, Marcos
• Application Number:
  US11/881,041
• Publication Number:
  US 20080081676A1
• Time in Patent Office: 1,644 Days
• Field of Search: 455/572, 455/574, 455/127.1, 455/0.5, 4553431-3432, 455/423, 455/67.11, 323/234, 370/311
• US Class Current: 455/574
• CPC Class Codes: G05B 19/4185 characterised by the network communication
• CPC Class Codes: G05B 2219/25289 Energy saving, brown out, standby, sleep, powerdown modus for microcomputer
• CPC Class Codes: G05B 2219/31121 Fielddevice, field controller, interface connected to fieldbus
• CPC Class Codes: G05B 2219/32021 Energy management, balance and limit power to tools
• CPC Class Codes: G05B 2219/33192 Radio link, wireless
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals
• CPC Class Codes: Y02P 70/10 Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A field device includes a power control module, a network interface module that communicates over a wireless network, and a device interface module for operating transducers, such as a sensor or an actuator. The power control module controls distribution of electrical power so that the network interface module receives electrical power while it is attempting to join the wireless network. Once the network interface module has joined the wireless network, the power control module allows the network interface module and the device interface module to share electrical power.

Claims

1. A field device comprising:

a network interface module for communicating over a wireless network;

a device interface module for operating a transducer;

a power control for determining how available electrical power is shared by the network interface module and the device interface module, wherein the power control is configured to monitor a network state of the network interface module and independently control allocation of power between the network interface module and the device interface module, wherein a portion of the available electrical power allocated to one of the network interface module and the device interface module is not available to the other of the network interface module and the device interface module; and

software or firmware utilized by the power control that provides a power allocation priority sequence as a function of the monitored network state of the network interface module, wherein the power allocation priority sequence prioritizes allocation of power by the power control to the network interface module when the network interface module is not connected to the wireless network, regardless of status of the device interface module, and the device interface module has an increased share of available electrical power after the network interface module has joined the wireless network.

2. The field device of claim 1 and further comprising:

a wireless transceiver for transmitting messages from the network interface module to the network and for receiving messages to the network interface module from the network.

3. The field device of claim 1 and further comprising:

a power source for providing electrical power.

4. The field device of claim 3, wherein the power source includes at least one of a battery, a solar cell, a thermoelectric cell, an atomic battery, an energy scavenger, and a storage capacitor.

5. The field device of claim 1, wherein the transducer includes at least one sensor or actuator.

6. The field device of claim 1, wherein the power control determines how available electrical power is shared so as to minimize total power consumption at any given time.

7. The field device of claim 1, wherein upon the device interface module waking up, the power control module determines whether to continue to allocate electrical power to the device interface module depending on whether the network interface is currently connected to the wireless network.

8. The field device of claim 1, wherein the wireless network is configured as a mesh network.

9. The field device of claim 1, wherein the joining process is defined as including one or more of:

a search for existing network nodes, an establishment of a handshake protocol with a neighboring field device, a provision of a neighbor list addressed to a network manager, an implementation of configuration information from the network manager, and an establishment of one or more links in the wireless network from the field device.

10. A field device comprising:

a wireless transceiver for transmitting messages to and receiving messages from a wireless network;

a network interface module for controlling operation of the wireless transceiver;

a transducer;

a device interface module for controlling operation of the transducer;

a power source;

a power control module configured to monitor a network state of the network interface module and independently control allocation of power between the network interface module and the device interface module;

software or firmware utilized by the power control module that provides a power allocation priority sequence as a function of the monitored network state of the network interface module, wherein the power allocation priority sequence prioritizes allocation of power by the power control module to the network interface module when the network interface module is not connected to the wireless network, regardless of status of the device interface module.

11. The field device of claim 10, wherein the power control module allocates all available power to the network interface module except for sleep mode power allocated to the device interface module by the power control module when network connection to the wireless network has not been established.

12. The field device of claim 11, wherein the power control module allocates power when network connection to the wireless network has been established so that both the network interface module and the device interface module receive power.

13. The field device of claim 10, wherein the network interface module controls power to the transceiver, and the device interface module controls power to the transducer.

14. The field device of claim 10, wherein the power source includes at least one of a battery, a solar cell, a thermoelectric cell, an atomic battery, an energy scavenger, and a storage capacitor.

15. The field device of claim 10, wherein the transducer includes at least one sensor.

16. The field device of claim 10, wherein the transducer includes an actuator.

17. The field device of claim 10, wherein when the device interface module wakes up, the power control module determines whether the network interface module has an established network connection.

18. The field device of claim 10, wherein the power control module allocates a greater portion of the power to the network interface module when a network connection is not established than when a network connection is established.

19. The field device of claim 10, wherein the wireless network is configured as a mesh network.

20. A method of operating a field device including a power source, a wireless transceiver, a transducer, a network interface module and a device interface module, the method comprising:

determining whether the network interface module is connected to a wireless network through the wireless transceiver;

monitoring the determination of whether the network interface module is connected to the wireless network through the wireless transceiver with a power control module that governs power allocation between the network interface module and the device interface module;

establishing a power allocation priority schedule as a function of the monitored determination of whether the network interface module is connected to the wireless network through the wireless transceiver, wherein the power allocation priority schedule prioritizes allocation of power to the network interface module when the network interface module is not connected to the wireless network, regardless of status of the device interface module; and

allocating available power from the power source independently between the network interface module and the device interface module with the power control module based upon the monitored determination of whether the network interface module is connected to the wireless network and the power allocation priority schedule, wherein a portion of the available electrical allocated for one of the network interface module and the device interface module is not available to the other of the network interface module and the device interface module.

21. The method of claim 20, wherein allocating power comprises:

allocating all available power to the network interface module except for sleep mode power allocated to the device interface module when the network interface module is not connected to the wireless network; and

allocating power to both the network interface module and the device interface module for waking operation when the network interface module is connected to the wireless network.

22. The method of claim 20 and further comprising:

powering the wireless transceiver with power from the network interface module; and

powering the transducer with power from the device interface module.

23. The method of claim 20, wherein determining whether the network interface module is connected to the wireless network occurs when the device interface module wakes up.