DISTRIBUTED CONTROL METHOD, DISTRIBUTED CONTROL SYSTEM, AND NON-TRANSITORY COMPUTER-READABLE STORAGE MEDIUM

• US 20170109995A1
• Filed: 10/17/2016
• Published: 04/20/2017
• Est. Priority Date: 10/20/2015
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: UENO, Hitoshi, Abiru, Kenichi
• Granted Patent: US 9,911,304 B2
• Time in Patent Office: Days
• CPC Class Codes: G05B 19/41815 characterised by the cooperation between machine tools, manipulators and conveyor or other workpiece supply system, workcell
• CPC Class Codes: G05B 19/4184 characterised by fault tolerance, reliability of production system
• CPC Class Codes: G05B 2219/25056 Automatic configuration of monitoring, control system as function of operator input, events
• CPC Class Codes: G05B 2219/25413 Interrupt, event, state change triggered
• CPC Class Codes: G08B 21/18 Status alarms G08B21/02 takes precedence
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A distributed control method in a distributed control system including a process executed by a by a first notification device, the process including notifying a detection of a first event to a second notification device, storing, in a storage device, acknowledgement information associating an event identifier indicating the first event with a device identifier indicating the second notification device when a negative acknowledgement is received from the second notification device, determining whether the event identifier indicating the first event is stored in the storage device or not when a request for a notification of the detection of the first event is received from a third notification device, and deleting, from the storage device, a device identifier associated with the event identifier indicating the first event when it is determined that the event identifier indicating the first event is stored in the storage device.

Claims

1. A distributed control method in a distributed control system including a plurality of notification devices and at least one detection device which notifies detection of an event to a notification device that corresponds to a position of the detection device among from the plurality of notification devices, the distributed control method including a process executed by a by a first notification device included in the plurality of notification devices, the process comprising:

notifying a detection of a first event to a second notification device included in the plurality of notification devices when the detection of the first event is received from the at least one detection device detecting the first event, the first notification device being capable of receiving a detection of the first event from the at least one detection device, the second notification device being capable of receiving a detection of a second event from the at least one detection device;

storing, in a storage device, acknowledgement information associating an event identifier indicating the first event with a device identifier indicating the second notification device when a negative acknowledgement indicating that a processing according to the detection of the first event is not able to be executed is received from the second notification device;

determining whether the event identifier indicating the first event is stored in the storage device or not when a request for a notification of the detection of the first event is received from a third notification device included in the plurality of notification devices, the third notification device being capable of receiving a detection of a second event is from the at least one detection device; and

deleting, from the storage device, a device identifier associated with the event identifier indicating the first event when it is determined that the event identifier indicating the first event is stored in the storage device.

2. The distributed control method according to claim 1, wherein the processing according to the detection of the first event includes an access to the at least one detection device to receive the detection of the second event.

3. The distributed control method according to claim 1, wherein, in the determining, it is determined whether or not number of pieces of the device identifier associated with the event identifier indicating the first event included in the storage device is equal to number of notification devices which have transmitted the request for the notification of the detection of the first event when the request from the third notification device is received after receiving the negative acknowledgement;

and

wherein, in the deleting, the device identifier associated with the event identifier indicating the first event is deleted from the storage device when it is determined that the number of pieces of the device identifier associated with the event identifier indicating the first event included in the storage device is equal to the number of notification devices which have transmitted the request for a notification of the detection of the first event.

4. The distributed control method according to claim 1,

wherein, in the notifying process, the detection of the first event is further notified to the third notification device when the detection of the first event is received from the at least one detection device before receiving the negative acknowledgement and after receiving the request from the third notification device,

wherein, in the determining, it is determined whether or not the number of pieces of the device identifier associated with the event identifier indicating the first event included in the storage device is equal to the number of notification devices which have transmitted the request for the notification of the detection of the first event in response to receiving of the negative acknowledgement;

wherein the storage device further storing notification destination information associating the event identifier indicating the first event with the device identifier indicating the second notification device; and

wherein, in the deleting, wherein, in the deleting, the device identifier associated with the event identifier indicating the first event is deleted from both the acknowledgement information and the notification destination information when it is determined that the number of pieces of the device identifier associated with the event identifier indicating the first event included in the acknowledgement information is equal to the number of notification devices which have transmitted the request for a notification of the detection of the first event.

5. The distributed control method according to claim 1,

wherein in the storing, the device identifier is further associated with a value indicating a time limit based on a time of receiving the negative acknowledgement,

wherein in the determining, it is determined whether or not number of pieces of the device identifier associated with the event identifier indicating the first event included in the storage device is equal to number of notification devices which have transmitted the request for the notification of the detection of the first event when a current time becomes the time limit, and

wherein, in the deleting, the device identifier associated with the event identifier indicating the first event is deleted from the storage device when it is determined that the number of pieces of the device identifier associated with the event identifier indicating the first event included in the storage device is equal to the number of notification devices which have transmitted the request for a notification of the detection of the first event.

6. A distributed control system, comprising:

a plurality of notification devices, each of the plurality of notification devices including;

a first memory; and

a first processor coupled to the memory; and

at least one detection device including;

a second memory; and

a second processor coupled to the memory and the second processor configured to;

notify detection of an event to a notification device determined based on a position of the at least one detection device in the plurality of notification devices;

wherein

a first notification device is included in the plurality of notification devices, the first processor included in the first notification device being configured to;

notify a detection of a first event to a second notification device included in the plurality of notification devices when the detection of the first event is received from the at least one detection device detecting the first event, the first notification device being capable of receiving a detection of the first event from the at least one detection device, the second notification device being capable of receiving a detection of a second event from the at least one detection device;

store, in the memory, acknowledgement information associating an event identifier indicating the first event with a device identifier indicating the second notification device when a negative acknowledgement indicating that a processing according to the detection of the first event is not able to be executed is received from the second notification device;

determine whether the event identifier indicating the first event is stored in the memory or not when a request for a notification of the detection of the first event is received from a third notification device included in the plurality of notification devices, the third notification device being capable of receiving a detection of a second event is from the at least one detection device; and

delete, from the memory, a device identifier associated with the event identifier indicating the first event when it is determined that the event identifier indicating the first event is stored in the memory.

7. A non-transitory computer-readable storage medium storing a distributed control program that causes a first notification device included in the distributed control system to execute a process, the distributed control system including a plurality of notification devices and at least one detection device which notifies detection of an event to a notification device determined based on a position of the at least one detection device in the plurality of notification devices, the process comprising:

notifying a detection of a first event to a second notification device included in the plurality of notification devices when the detection of the first event is received from the at least one detection device detecting the first event, the first notification device being capable of receiving a detection of the first event from the at least one detection device, the second notification device being capable of receiving a detection of a second event from the at least one detection device;

storing, in a storage device, acknowledgement information associating an event identifier indicating the first event with a device identifier indicating the second notification device when a negative acknowledgement indicating that a processing according to the detection of the first event is not able to be executed is received from the second notification device;

determining whether the event identifier indicating the first event is stored in the storage device or not when a request for a notification of the detection of the first event is received from a third notification device included in the plurality of notification devices, the third notification device being capable of receiving a detection of a second event is from the at least one detection device; and

deleting, from the storage device, a device identifier associated with the event identifier indicating the first event when it is determined that the event identifier indicating the first event is stored in the storage device.