Selective activation of field devices in low power wireless mesh networks

• US 7,986,657 B2
• Filed: 01/11/2007
• Issued: 07/26/2011
• Est. Priority Date: 01/11/2006
• Status: Active Grant

• Current Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Original Assignee: Fisher-Rosemount Systems Incorporated (Emerson Electric Company)
• Inventors: Dobrowski, Patrick M., Orth, Kelly M., Lovegren, Eric R., Stotz, Kyle L.
• Primary Examiner(s): Hu; Jinsong
• Assistant Examiner(s): TAYLOR, NATHAN SCOTT
• Application Number:
  US11/652,395
• Publication Number:
  US 20070161352A1
• Time in Patent Office: 1,657 Days
• Field of Search: 709/224, 710/18, 370/311, 370/255, 370/395.31, 370/341, 370/328, 455/414.1, 455/7
• US Class Current: 370/328
• CPC Class Codes: G05B 2219/31162 Wireless lan
• CPC Class Codes: H04L 41/00 Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 41/22 comprising specially adapted graphical user interfaces [GUI]
• CPC Class Codes: H04L 43/045 for graphical visualisation of monitoring data
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/28 using route fault recovery
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/28 in relation to timing considerations
• CPC Class Codes: H04L 47/34 ensuring sequence integrity, e.g. using sequence numbers
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 16/22 Traffic simulation tools or models
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 28/02 Traffic management, e.g. flow control or congestion control
• CPC Class Codes: H04W 4/18 Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding
• CPC Class Codes: H04W 40/08 based on transmission power
• CPC Class Codes: H04W 40/10 based on available power or energy
• CPC Class Codes: H04W 40/22 using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
• CPC Class Codes: H04W 40/24 : Connectivity information management, e.g. connectivity discovery or connectivity update
• CPC Class Codes: H04W 52/02 : Power saving arrangements in wired systems H04L12/12; signaling of mobile application services, e.g. low battery notifications H04W4/20
• CPC Class Codes: H04W 52/0225 : using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: H04W 52/0229 : where the received signal is a wanted signal
• CPC Class Codes: H04W 56/00 : Synchronisation arrangements
• CPC Class Codes: H04W 76/20 : Manipulation of established connections
• CPC Class Codes: H04W 8/04 : Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 8/26 : Network addressing or numbering for mobility support
• CPC Class Codes: H04W 80/00 : Wireless network protocols or protocol adaptations to wireless operation
• CPC Class Codes: H04W 84/18 : Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/16 : Gateway arrangements
• CPC Class Codes: H04W 92/00 : Interfaces specially adapted for wireless communication networks
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

A control system uses a wireless network to provided communication between a host computer and field devices. The field devices are normally maintained in a lower power or sleep state. Only field devices that will be involved in a communication with the host computer are turned On and maintained On until communication between the field devices and the host computer is completed.

Claims

1. An industrial process control system comprising:

a host;

a field device; and

a wireless network for routing wireless messages between the host and the field device, the wireless network including a plurality of nodes and a gateway, wherein the gateway wirelessly communicates messages provided by the host to the nodes and controls an On/Off activation schedule of the nodes;

wherein in response to a communication period initiated by the host with a selected field device, the node associated with the selected field device generates a command to operate the selected field device in a full power state; and

wherein the node associated with the selected field device maintains the selected field device in the full power state through On/Off cycles of the activation schedule until communication between the host and the field device is complete, at which time the node generates a command to operate the selected field device in a low power state until a subsequent communication period initiated by the host.

2. An industrial process control system comprising:

a plurality of field devices;

a host for sending control messages to field devices and receiving response messages from the field devices; and

a wireless network for routing wireless messages among a plurality of nodes, each field device being associated with one of the plurality of nodes, wherein the wireless messages include content of the control messages and an address of a selected field device or content of response messages from the selected field device, the node associated with the selected field device generating a command to turn On the selected field device only in response to a control message from the host addressed to the selected field device,

wherein the node maintains the selected field device in the On state through On/Off cycles of the wireless network until communication between the host and the selected field device is complete, a which time the node associated with the selected field device generates a command to operate the selected field device in an Off state until a subsequent communication period initiated by the host.

3. The system of claim 2, wherein the node associated with the selected field device turns Off the selected field device at an end of communication between the host and the selected field device.

4. The system of claim 3, wherein the host provides a control message indicating the end of communication.

5. The system of claim 3, wherein the node associated with the selected field device identifies the end of communication by a period of inactivity in message traffic between the host and the selected field device.

6. The system of claim 2 wherein the node associated with the selected field device maintains the selected field device in a turn On state through On/Off activation cycles of the wireless network until communication between the host and the selected field device is completed.

7. The system of claim 2 wherein the node further comprises at least two field devices and only turns On the selected field device while leaving an unselected field device in a low power state.

8. A method of communicating between a host and field devices of an industrial process control system over a wireless network having a plurality of nodes that turn On/Off according to an activation schedule, the method comprising:

generating at the host a control message addressed to a field device;

generating a wireless message containing content of the control message including a node address;

transmitting the wireless message over the wireless network to the addressed node associated with the field device;

receiving the wireless message at the addressed node;

extracting the content of the control message from the wireless message;

generating a command to turn On only the field device to which the control message is addressed in response to the control message;

delivering the control message to the field device;

maintaining the field device to which the control message was addressed in the On state through On/Off cycles of the activation schedule associated with the plurality of nodes until communication between the host and the field device is complete; and

generating a command to turn Off the field device to which the control message was addressed until a subsequent communication period initiated by the host.

9. The method of claim 8 and further comprising:

generating a response message at the field device;

generating a wireless message including content of the response message;

transmitting the wireless message with the response message content over the wireless network;

receiving the wireless message with the response message content; and

delivering the response message to the host.

10. The method of claim 8 and further comprising:

maintaining the field device in a turned On state until communication between the host and the field device is complete, and then turning Off the field device.

11. The method of claim 10 and further comprising:

maintaining the field device in a turned Off state until another control message is received that is addressed to the field device.

12. The method of claim 8 and further comprising:

maintaining the field device in the turned On state through one or more scheduled On/Off cycles until communication between the host and the field device is complete.

13. A method of operating a wireless mesh network having a plurality of nodes capable of transmitting to and receiving messages from a field device associated with and selectively activated by commands generated by one of the plurality of nodes, the method comprising:

synchronizing the nodes of the network to a global regular active schedule that defines when messages can be transmitted and received by the nodes;

generating commands to selectively activate only those field devices to which a message will be sent during an active period of the schedule; and

maintaining those field devices to which a message is sent in an activated state despite the global regular active schedule associated with the nodes of the network until communication with the selected field devices is complete, at which time commands are generated to operate the selected field devices in a de-activated state until a subsequent communication period initiated for selected field devices.

14. The method of claim 13 and further comprising:

maintaining the field devices that are activated in an active state through one or more periods when messages are not being transmitted or received by the nodes until communication with the field devices is completed.

15. A method of communicating messages in a wireless mesh network having a plurality of nodes and having a plurality of field devices, each field device associated with one of the plurality of nodes wherein an On/Off state of each field device is controlled by commands generated by the node with which the field device is associated, the method comprising:

activating nodes to transmit and receive messages during an active period according to a global activation schedule;

generating commands to control which field devices are turned On during the active period of the schedule based upon whether messages will be sent to the field devices during the active period;

maintaining those field devices to which the message will be sent in the On state despite the global activation schedule of the nodes until communication with the field device is complete; and

generating commands to turn Off the field devices until a subsequent communication period is initiated with the field device.

16. The method of claim 15 and further comprising:

maintaining the field devices that are turned On in a turned On state until communication with the field device is completed.

17. The method of claim 15 and further comprising:

maintaining the field devices that are turned On in a turned On state through one or more active periods until communication with the field device is completed.