Support for Network Management and Device Communications in a Wireless Network

• US 20090010204A1
• Filed: 04/10/2008
• Published: 01/08/2009
• Est. Priority Date: 04/13/2007
• Status: Active Grant

• Current Assignee: FieldComm Group, Inc.
• Original Assignee: Hart Communication Foundation (FieldComm Group, Inc.)
• Inventors: Nixon, Mark J., Rotvold, Eric D., Pratt, Wallace A. JR., Pramanik, Robin S., Lennvall, Tomas P.
• Granted Patent: US 8,942,219 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: G01D 21/00 Measuring or testing not otherwise provided for
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 56/002 Mutual synchronization
• CPC Class Codes: H04W 80/00 Wireless network protocols or protocol adaptations to wireless operation

Abstract

A method of efficiently operating a wireless communication network in a process control environment, such that the wireless communication network includes a plurality of field devices, includes defining a communication protocol for supporting wireless communications between pairs of the plurality of field devices, including providing a set of protocol commands, transferring process control data from at least some of the plurality of field devices using a first subset of the set of protocol commands of the communication protocol, and transferring network management data to at least some of the plurality of field devices using a second subset of the set of protocol commands of the communication protocol.

Claims

1. A method of efficiently operating a wireless communication network in a process control environment, wherein the wireless communication network includes a plurality of field devices, the method comprising:

defining a communication protocol for supporting wireless communications between pairs of the plurality of field devices, including providing a set of protocol commands;

transferring process control data from at least some of the plurality of field devices using a first subset of the set of protocol commands of the communication protocol; and

transferring network management data to at least some of the plurality of field devices using a second subset of the set of protocol commands of the communication protocol.

2. The method of claim 1, wherein defining a communication protocol includes:

defining a plurality of protocol layers of the communication protocol;

associating the first subset of the set of protocol commands with a first one of the plurality of protocol layers; and

associating the second subset of the set of protocol commands with a second one of the plurality of protocol layers.

3. The method of claim 1, wherein providing a set of protocol commands includes providing at least some commands of the Highway Addressable Remote Transducer (HART®

) communication protocol.

4. The method of claim 1, further comprising:

transferring alert or event data from at least some of the plurality of field devices using a third subset of the set of protocol commands of the communication protocol.

5. The method of claim 1, wherein transferring network management data includes associating network management data with a first level of priority;

and wherein

transferring process control data includes associating process control data with a second priority.

6. The method of claim 1, further comprising:

defining a plurality of concurrent overlapping superframes as repeating cycles of consecutively scheduled communication timeslots of a certain duration;

wherein at least two of the plurality of concurrent overlapping superframes include a different number of communication timeslots.

7. The method of claim 6, wherein defining a plurality of concurrent superframes further includes:

associating a first one of the plurality of concurrent superframes with the network management data;

wherein the first one of the plurality of concurrent superframes has a first number of communication timeslots and wherein each of the plurality of field devices receives the network management data in at least one of the communication timeslots of the first one of the plurality of concurrent superframes;

associating a second one of the plurality of concurrent superframes with an update of a first one of the plurality of field devices;

wherein the first one of the plurality of field devices originates process data within one of the communication timeslots of the second one of the plurality of concurrent superframes and wherein a number of timeslots in the second one of the plurality of concurrent superframes corresponds to the update rate of the first one of the plurality of field devices; and

associating a third one of the plurality of concurrent superframes with an update of a second one of the plurality of field devices;

wherein the second one of the plurality of field devices originates process data within one of the communication timeslots of the third one of the plurality of concurrent superframes and wherein a number of timeslots in the third one of the plurality of concurrent superframes corresponds to the update rate of the second one of the plurality of field devices.

8. The method of claim 6, further comprising:

establishing a plurality of direct wireless connections between pairs of the plurality of field devices;

generating a plurality of directed graphs defining communication paths between pairs of the plurality of field devices based on a topology of the wireless network, wherein each directed graph includes at least one of the plurality direct connections;

associating one of the plurality of directed graphs with the network management data; and

associating another of the plurality of directed graphs with the process control data.

9. The method of claim 1, wherein transferring process control data includes transferring the process control data to a gateway device communicatively coupled to a plant automation network;

and wherein transferring network management data includes transferring the network management data to a network manager responsible for at least one of a scheduling scheme and a routing scheme in the wireless communication network.

10. The method of claim 1, further comprising tunneling data associated with another communication protocol using a tunneling subset of the set of protocol commands.

11. A method of transferring data in a wireless mesh communication network including a plurality of wireless field devices and operating in a process control environment, the method comprising:

generating a communication schedule for the wireless mesh communication network, including;

defining a communication timeslot of a certain duration;

defining a plurality of concurrent overlapping superframes as repeating cycles of a number of consecutively scheduled communication timeslots;

associating a first one of the plurality of concurrent superframes with network management data; and

associating a subset of the plurality of concurrent superframes with process control data, wherein the subset does not include the first one of the plurality of concurrent superframes; and

scheduling communications of each of the plurality of wireless field devices within communication timeslots associated with the plurality of concurrent superframes.

12. The method of claim 11, wherein associating a first one of the plurality of concurrent superframes with network management data includes associating the first one of the plurality of concurrent superframes with data related to dynamic formation, configuration, and maintenance of the wireless mesh communication network;

and wherein associating a subset of the plurality of concurrent superframes with process control data includes associating the subset with data related to measurements obtained by some at least some of the plurality of wireless field devices and to commands controlling a respective operation of at least some of the plurality of wireless field devices.

13. The method of claim 11, wherein associating a subset of the plurality of concurrent superframes with process control data includes:

associating each superframe in the subset with a periodic update of a respective one of the plurality of wireless field devices;

wherein a number of communication timeslots in the superframe is proportional to a rate of the periodic update.

14. The method of claim 11, further comprising:

establishing a plurality of direct wireless connections between pairs of the plurality of wireless field devices;

generating a plurality of directed graphs defining communication paths from or to each the plurality of field devices, wherein each directed graph includes at least one of the plurality direct connections; and

associating each scheduled communication timeslot with one of the plurality of direct wireless connections associated with one or more of the plurality of directed graphs.

15. The method of claim 14, wherein generating a plurality of directed graphs includes:

exclusively associating a first one of the plurality of directed graphs with network management data; and

exclusively associating a second one of the plurality of directed graphs with process data.

16. The method of claim 11, further comprising:

associating the network management data with a first level of priority;

associating the process data with a second level of priority;

associating each of the plurality of wireless field devices with a priority mask including one or both of the first level of priority and the second level of priority; and

wherein

scheduling communications includes, at each of the plurality of wireless field devices;

scheduling a communication timeslot within the first one of the plurality of concurrent superframes only if a priority mask of the wireless field device includes the first level of priority.

17. The method of claim 16, further comprising:

dynamically updating a priority mask at one of the plurality of wireless field devices in response to detecting a change in the wireless mesh communication network.

18. The method of claim 11, wherein associating a first one of the plurality of concurrent superframes with network management data includes associating the first one of the plurality of concurrent superframes with a length equal to an update rate of a slowest one of the plurality of wireless field devices;

wherein the length of the first one of the plurality of concurrent superframes corresponds to a number of communication timeslots.

19. A method of transferring data in a wireless mesh communication network including a plurality of wireless network devices and operating in a process control environment, the method comprising:

generating a communication schedule for the wireless mesh communication network, including defining a plurality of concurrent overlapping superframes as repeating cycles of a number of consecutively scheduled communication timeslots of a fixed duration;

generating a plurality of directed graphs defining communication paths in a direction of one of toward or away from each the plurality of network devices, wherein each directed graph includes at least one of a plurality direct connections between pairs of the plurality of network devices; and

assigning transmission opportunities to a plurality of communication timeslots, wherein each of the plurality of communication timeslots is scheduled within one of the plurality of concurrent overlapping superframes, and wherein each of the plurality of communication timeslots is associated with one of the plurality direct connections associated with one of the plurality of directed graphs, including;

associating a first one of the plurality of communication timeslots with transmission of process data; and

associating a first one of the plurality of communication timeslots with transmission of network management data.

20. The method of claim 19, wherein the plurality of wireless network devices includes a plurality of wireless field devices producing the process data.

21. The method of claim 19, wherein assigning transmission opportunities to a plurality of communication timeslots includes associating each transmission opportunity with a command of a communication protocol supported by each of the plurality of network devices.

22. The method of claim 19, wherein assigning transmission opportunities to a plurality of communication timeslots further comprises:

associating a third one of the plurality of communication timeslots with transmission of device management data.

23. The method of claim 22, wherein the device management data includes at least one of device diagnostic, device calibration, or device configuration data.

24. A method of efficiently operating a wireless communication network in a process control environment, wherein the wireless communication network includes a plurality of field devices, the method comprising:

defining a communication protocol for supporting wireless communications between pairs of the plurality of field devices, including providing a set of protocol commands;

transferring device data from at least some of the plurality of field devices using a first subset of the set of protocol commands of the communication protocol; and

transferring network management data to at least some of the plurality of field devices using a second subset of the set of protocol commands of the communication protocol.

25. The method of claim 24, wherein transferring device data includes transferring device-specific management data;

wherein at least two of the plurality of field devices are associated with different types of management data.

26. The method of claim 24, wherein transferring device data includes transferring an alarm from one of the plurality of field devices.

27. The method of claim 26, wherein transferring an alarm includes:

transmitting the alarm from the one of the plurality of field devices to a gateway connecting the wireless communication network to an external network;

retaining the alarm at the one of the plurality of field devices; and

discarding the alarm in response to receiving a confirmation from the gateway.