Efficient Addressing in Wireless Hart Protocol

• US 20090010203A1
• 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 8,570,922 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04L 61/5038 for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 84/10 Small scale networks; Flat hierarchical networks
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface

Abstract

A method of providing a wireless extension to a wired protocol for transferring data to and from a field device operating in a process control environment via a wired connection, wherein the wired protocol and the wireless extension to the wired protocol have at least one protocol layer in common includes associating a unique address consistent with an addressing scheme of the wired protocol with each of a plurality of wireless devices operating in the process control environment and forming a wireless network, such that a data packet is routed between two of the plurality of wireless devices based on the unique address; associating a network identifier with the plurality of wireless devices; forming, for each of the plurality of wireless devices, a global address including the respective unique address and the network identifier in accordance with a second addressing scheme; and providing access to an external host operating outside the wireless network to each of the plurality of wireless devices based on the global address associated with the wireless device specified at the external host.

Claims

1. A method of providing a wireless extension to a wired protocol for transferring data to and from a field device operating in a process control environment via a wired connection, wherein the wired protocol and the wireless extension to the wired protocol have at least one protocol layer in common, the method comprising:

associating a unique address consistent with an addressing scheme of the wired protocol with each of a plurality of wireless devices operating in the process control environment and forming a wireless network;

wherein a data packet is routed between two of the plurality of wireless devices based on the unique address;

associating a network identifier with the plurality of wireless devices;

forming, for each of the plurality of wireless devices, a global address including the respective unique address and the network identifier in accordance with a second addressing scheme; and

providing access to an external host operating outside the wireless network to each of the plurality of wireless devices based on the global address associated with the wireless device specified at the external host.

2. The method of claim 1, wherein forming a global address consists of appending an Organizationally Unique Identifier (OUI) allocated by the Institute of Electrical and Electronics Engineers (IEEE) to the unique address.

3. The method of claim 2, wherein appending the OUI is appending the OUI associated with the HART®

communication protocol.

4. The method of claim 1, further comprising:

associating the addressing scheme of the wired protocol with a network layer of the wireless protocol; and

associating the second addressing scheme with a data link layer of the wireless protocol;

wherein the network layer of the wireless protocol is layered over the data link layer of the wireless protocol.

5. The method of claim 1, wherein associating a unique address consistent with an addressing scheme of the wired protocol with each of a plurality of wireless devices includes:

associating a unique device identifier occupying a first number of bytes with the unique address; and

associating an expanded device type code occupying a second number of bytes with the unique address;

wherein each device having a same type and a same manufactures shares the same expanded device type code.

6. The method of claim 5, wherein a sum of the first number of bytes and the second number of bytes is five bytes;

wherein the network identifier is a three byte Organizationally Unique Identifier (OUI) allocated by the Institute of Electrical and Electronics Engineers (IEEE).

7. The method of claim 1, wherein the global address is consistent with an eight byte Extended Unique Identifier (EUI-64) IEEE standard.

8. The method of claim 1, wherein the addressing scheme of the wired protocol is a HART addressing scheme.

9. The method of claim 1, further comprising associating a nickname with each of the plurality of wireless network devices;

wherein the nickname occupies a smaller number of bytes than a unique address consistent with the addressing scheme of the wired protocol; and

wherein each of the plurality of wireless devices can route data to at least one the plurality of wireless devices based on either the nickname of the at least one the plurality of wireless devices or the unique address of the at least one the plurality of wireless devices.

10. A communication network operating in a process control environment, comprising:

a first device having only a wired connection to a Distributed Control System (DCS) and supporting a wired protocol for transferring process control data;

the first device including a unique wired address associated with the wired protocol;

a second device having a wireless connection to the DCS and supporting a wireless protocol for transferring process control data;

the first device including a unique wireless address associated with the wired protocol; and

a routing device transferring data between the first device and the DCS and between the second device and the DCS based on an address associated with the wired protocol.

11. The communication network of claim 10, wherein the routing device is a Field Termination Assembly (FTA) coupled to the DCS via at least one pair of wires.

12. The communication network of claim 11, wherein the DCS propagates data to the FTA via the at least one pair of wires in accordance with the HART communication protocol;

and wherein the unique wireless address associated with the wired protocol is a HART address.

13. The communication network of claim 10, wherein the second device further includes a network identifier shared with at least a third device having a wireless connection to the DCS.

14. A method of providing an efficient addressing in a wireless mesh network operating in a process control environment, the method comprising:

associating a unique first address including a device identifier and a device type code with each of a plurality of wireless devices participating in the wireless mesh network;

associating a unique second address with each of a plurality of wireless devices participating in the wireless mesh network;

routing data between each of the plurality of wireless devices and at least one other of the plurality of wireless devices based on the unique first address or on the unique second address; and

routing data between each of the plurality of wireless devices and a host operating outside the wireless mesh network based on a global address including the unique first address and a constant value associated with the wireless mesh network.

15. The method of claim 14, routing data between each of the plurality of wireless devices and a host operating outside the wireless mesh network is routing data based on an address consistent with one of the EUI IEEE standards.

16. The method of claim 14, wherein associating a unique first address with each of a plurality of wireless devices is associating the each of a plurality of wireless devices with a unique address consistent with a wired protocol;

wherein routing data between each of the plurality of wireless devices and at least one other of the plurality of wireless devices including using a wireless protocol; and

wherein the wireless protocol extends the wired protocol by supporting at least an uppermost layer of a protocol stack associated with the wired protocol.

17. The method of claim 16, wherein the wired protocol is HART®

.