APPARATUS AND METHOD FOR SUPPORTING WIRELESS ACTUATORS AND OTHER DEVICES IN PROCESS CONTROL SYSTEMS

• US 20100272093A1
• Filed: 11/23/2009
• Published: 10/28/2010
• Est. Priority Date: 04/24/2009
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Chernoguzov, Alexander, Budampati, Ramakrishna S., Raravi, Channabasavaraj, Kolavennu, Soumitri N., Pulini, Christopher
• Granted Patent: US 8,837,354 B2
• Time in Patent Office: Days
• US Class Current: 370/348
• CPC Class Codes: G05B 19/4185 characterised by the network communication
• CPC Class Codes: G05B 2219/31162 Wireless lan
• CPC Class Codes: G05B 2219/33192 Radio link, wireless
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A system includes a wireless leaf node configured to modify operation of an industrial process. The system also includes a plurality of wireless access points configured to transmit data to the wireless leaf node in specified time slots and to receive an acknowledgement from the wireless leaf node in response to successful receipt of the data by the wireless leaf node. Various communication schemes are disclosed for supporting communications between the wireless leaf node and the access points. Each access point could also include a local slot manager configured to assign the specified time slots for that access point to communicate with the wireless leaf node. The wireless leaf node could represent a wireless actuator.

Claims

1. A system comprising:

a wireless leaf node configured to modify operation of an industrial process; and

a plurality of wireless access points configured to transmit data to the wireless leaf node in specified time slots and to receive an acknowledgement from the wireless leaf node in response to successful receipt of the data by the wireless leaf node.

2. The system of claim 1, wherein first and second ones of the access points are both configured to:

transmit the data to the wireless leaf node during a first time period;

if no acknowledgement is received, retransmit the data to the wireless leaf node during a subsequent second time period; and

if no acknowledgement is received, retransmit the data to the wireless leaf node after a subsequent third time period during a subsequent fourth time period.

3. The system of claim 2, wherein the first and second access points are further configured to:

receive a ping from the wireless leaf node before transmitting the data to the wireless leaf node during at least one of the first, second, and fourth time periods.

4. The system of claim 1, wherein a first one of the access points is configured to:

transmit the data to the wireless leaf node during a first time period;

if no acknowledgement is received, retransmit the data to the wireless leaf node during a subsequent second time period; and

if no acknowledgement is received, retransmit the data to the wireless leaf node after a subsequent third time period during a subsequent fourth time period; and

wherein a second one of the access points is configured to transmit a chirp or dummy message to the wireless leaf node during at least one of the first, second, and fourth time periods.

5. The system of claim 1, wherein:

a first one of the access points is configured to transmit the data to the wireless leaf node during a first time period and, if no acknowledgement is received, to retransmit the data to the wireless leaf node at least one of;

during a subsequent second time period and after a subsequent third time period during a subsequent fourth time period; and

a second one of the access points is configured to transmit the data to the wireless leaf node during a subsequent fifth time period and, if no acknowledgement is received, to retransmit the data to the wireless leaf node at least one of;

during a subsequent sixth time period and after a subsequent seventh time period during a subsequent eighth time period.

6. The system of claim 1, wherein:

first and second ones of the access points are configured to transmit the data to the wireless leaf node during first and second time periods, respectively;

if no acknowledgement is received, the first access point is configured to retransmit the data to the wireless leaf node after a subsequent third time period during a subsequent fourth time period;

if no acknowledgement is received, the second access point is configured to retransmit the data to the wireless leaf node after a subsequent fifth time period during a subsequent sixth time period;

if no acknowledgement is received, the first access point is configured to retransmit the data to the wireless leaf node after a subsequent seventh time period during a subsequent eighth time period; and

if no acknowledgement is received, the second access point is configured to retransmit the data to the wireless leaf node after a subsequent ninth time period during a subsequent tenth time period.

7. The system of claim 1, wherein the wireless leaf node comprises a wireless actuator.

8. The system of claim 1, wherein each access point comprises a local slot manager configured to assign the specified time slots for that access point to communicate with the wireless leaf node.

9. The system of claim 8, wherein each local slot manager is configured to assign multiple time slots to the wireless leaf node in response to a multi-slot request from the wireless leaf node.

10. The system of claim 8, wherein each local slot manager is configured to assign one time slot to the wireless leaf node in response to each of multiple slot requests from the wireless leaf node.

11. An access point comprising:

at least one transceiver configured to transmit data to a wireless leaf node that is configured to modify operation of an industrial process; and

a controller configured to initiate transmission of the data to the wireless leaf node in specified time slots, the controller configured to identify the specified time slots in cooperation with a second access point that is configured to transmit the data to the wireless leaf node;

wherein the at least one transceiver is also configured to receive an acknowledgement from the wireless leaf node in response to successful receipt of the data by the wireless leaf node.

12. The access point of claim 11, wherein the controller is configured to identify the time slots such that the access point:

transmits the data to the wireless leaf node during a first time period;

if no acknowledgement is received, retransmits the data to the wireless leaf node during a subsequent second time period; and

if no acknowledgement is received, retransmits the data to the wireless leaf node after a subsequent third time period during a subsequent fourth time period.

13. The access point of claim 12, wherein the controller is further configured to identify reception of a ping from the wireless leaf node before initiating transmission of the data to the wireless leaf node during at least one of the first, second, and fourth time periods.

14. The access point of claim 11, wherein the controller is configured to identify the time slots such that the access point:

transmits a chirp or dummy message to the wireless leaf node during a first time period;

if no acknowledgement is received, retransmits the chirp or dummy message to the wireless leaf node during a subsequent second time period; and

if no acknowledgement is received, retransmits the chirp or dummy message to the wireless leaf node after a subsequent third time period during a subsequent fourth time period.

15. The access point of claim 11, wherein the controller is configured to assign the time slots such that the access point:

transmits the data to the wireless leaf node during a first time period and, if no acknowledgement is received, retransmits the data to the wireless leaf node at least one of;

during a subsequent second time period and after a subsequent third time period during a subsequent fourth time period; and

if no acknowledgement is received, allows the second access point to transmit the data to the wireless leaf node at least one of;

during a subsequent fifth time period, during a subsequent sixth time period, and after a subsequent seventh time period during a subsequent eighth time period.

16. The access point of claim 11, wherein the controller is configured to assign the time slots such that the access point:

transmits the data to the wireless leaf node during a first time period;

allows the second access point to transmit the data to the wireless leaf node during a subsequent second time period;

if no acknowledgement is received, retransmits the data to the wireless leaf node after a subsequent third time period during a subsequent fourth time period;

if no acknowledgement is received, allows the second access point to retransmit the data to the wireless leaf node after a subsequent fifth time period during a subsequent sixth time period;

if no acknowledgement is received, retransmits the data to the wireless leaf node after a subsequent seventh time period during a subsequent eighth time period; and

if no acknowledgement is received, allows the second access point to retransmit the data to the wireless leaf node after a subsequent ninth time period during a subsequent tenth time period.

17. The access point of claim 11, wherein the controller is configured to assign multiple time slots to the wireless leaf node in response to a multi-slot request from the wireless leaf node.

18. The access point of claim 11, wherein the controller is configured to assign one time slot to the wireless leaf node in response to each of multiple slot requests from the wireless leaf node.

19. A method comprising:

receiving data from multiple access points at a wireless leaf node in an industrial control and automation system during one or more first time slots;

transmitting an acknowledgement to the multiple access points;

modifying operation of an industrial process based on the received data;

identifying a readback value associated with the modified operation of the industrial process; and

transmitting a message containing the readback value to the multiple access points during one or more second time slots.

20. The method of claim 19, further comprising:

transmitting a multi-slot request to the multiple access points, the first and second time slots identified in response to the multi-slot request.