Method in a wireless process control system for reducing power consumption, and a controller and computer program products

• US 8,873,444 B2
• Filed: 12/24/2012
• Issued: 10/28/2014
• Est. Priority Date: 06/24/2010
• Status: Active Grant

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: ABB Research Ltd. (ABB Ltd.)
• Inventors: Tiberi, Ubaldo, Isaksson, Alf, Landernas, Krister
• Primary Examiner(s): Chery, Dady
• Application Number:
  US13/726,327
• Publication Number:
  US 20130107750A1
• Time in Patent Office: 673 Days
• Field of Search: 370/252, 370/241, 370/242, 370/230, 370/229, 370/318, 370/311
• US Class Current: 370/311
• CPC Class Codes: G06F 1/3209 Monitoring remote activity, e.g. over telephone lines or network connections
• CPC Class Codes: H04Q 2209/40 using a wireless architecture
• CPC Class Codes: H04Q 2209/883 where the sensing device enters an active or inactive mode
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• 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: Y02D 30/70 in wireless communication networks

Abstract

A method in a wireless process control system for reducing power consumption of a sensor node of the wireless process control system. The wireless process control system further includes a controller in wireless communication with the sensor node wherein the sensor node is in a sleep mode. The method includes the steps of: predicting based on an error signal, when sensor measurement data is needed from the sensor node and determining an instant of time for communication between the controller and the sensor node based thereon; and the sensor node re-entering the sleep mode. The invention also relates to computer program products and a controller.

Claims

1. A method in a wireless process control system for reducing power consumption of a sensor node of said wireless process control system, said wireless process control system further comprising a controller comprising communication means for enabling wireless communication with said sensor node, wherein said sensor node is in a sleep mode, said method comprising the steps of:

predicting based on an error signal, when sensor measurement data is needed from said sensor node and determining an instant of time for communication between said controller and said sensor node based thereon, enabling the sensor node to timely wake up from its sleep mode, wherein predicting comprises comparing historical measurement data to set reference data, performing, in the sensor node, a required sensor measurement, the measurement further comprising;

comparing the measurement result to a threshold value, determining, in said sensor node, that the threshold value has been exceeded, and transmitting, in an empty time slot of a time-slotted communication protocol, a measurement value to said controller, and

said sensor node re-entering said sleep mode.

2. The method as claimed in claim 1, wherein said step of predicting is performed in said controller.

3. The method as claimed in claim 1, wherein said step of predicting comprises extrapolating the error signal based on said historical measurement data and said set reference data in order to determine the instant of time when next measurement data is needed.

4. The method as claimed in claim 1, wherein said wireless communication comprises use of a time-slotted communication protocol.

5. The method as claimed in claim 4, wherein said step of providing time information to said sensor node comprises said controller informing said sensor node about which time slot to use for a next-coming communication occasion.

6. The method as claimed in claim 1, wherein said step of said sensor node re-entering a sleep mode comprises said sensor node obtaining said instant of time and upon completed sensor measurement automatically entering said sleep mode.

7. The method as claimed in claim 1, comprising the further steps of obtaining, in said controller, information about latency in the wireless process control system;

and adjusting said instant of time accordingly.

8. A computer program product stored on a non-transitory computer readable storage medium, comprising computer readable program code means for causing a controller of a wireless process control system, to carry out a method in a wireless process control system for reducing power consumption of a sensor node of said wireless process control system, said wireless process control system further comprising a controller comprising communication means for enabling wireless communication with said sensor node, wherein said sensor node is in a sleep mode, said method comprising the steps of:

predicting based on an error signal, when sensor measurement data is needed from said sensor node and determining an instant of time for communication between said controller and said sensor node based thereon, enabling the sensor node to timely wake up from its sleep mode, wherein predicting comprises comparing historical measurement data to set reference data, performing, in the sensor node, a required sensor measurement, the measurement further comprising;

comparing the measurement result to a threshold value, determining, in said sensor node, that the threshold value has been exceeded, and transmitting, in an empty time slot of a time-slotted communication protocol, a measurement value to said controller, and

said sensor node reenter said sleep mode.

9. A controller for controlling processes within an automation system comprising a sensor node, the controller comprising communication means for enabling wireless communication with said sensor node, wherein said sensor node is in a sleep mode, said controller comprising:

means for predicting, based on an error signal, when sensor measurement data is needed from said sensor node performing the measurement further which further comprising;

comparing the measurement result to a threshold value, determining, in said sensor node, that the threshold value has been exceeded, and transmitting, in an empty time slot of a time-slotted communication protocol, a measurement value to said controller; and

determining an instant of time for communication between said controller and said sensor node based thereon, enabling the sensor node to timely wake up from its sleep mode, wherein predicting comprises comparing historical measurement data to set reference data, and

means for instructing said sensor node to re-enter said sleep mode.

10. The controller as claimed in claim 9, further comprising means for providing information to said sensor node about said instant of time, for enabling said sensor node to timely perform a required sensor measurement.