PLC for distributed control and distributed control system

• US 20070055388A1
• Filed: 07/28/2006
• Published: 03/08/2007
• Est. Priority Date: 08/02/2005
• Status: Active Grant

• Current Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Original Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Inventors: Araki, Tsutomu, Adams, Friedrich, Kato, Sutemaro, Niehaus, Michael
• Granted Patent: US 7,912,558 B2
• Time in Patent Office: Days
• US Class Current: 700/18
• CPC Class Codes: G05B 19/052 Linking several PLC's
• CPC Class Codes: G05B 2219/1204 Multiprocessing, several plc's, distributed logic control
• CPC Class Codes: G05B 2219/1208 Communication, exchange of control, I-O data between different plc,

Abstract

A PLC for distributed control includes a storage unit that stores common-data specifying information for specifying common data shared by a corresponding PLC and another PLC, a receiving unit that receives the common-data specifying information from another PLC, and a collating unit that collates the common-data specifying information stored in the storage unit with the common-data specifying information received by the receiving unit.

Claims

1. A PLC for distributed control that constitutes a distributed control system together with another PLC, the PLC comprising:

a storage unit that stores common-data specifying information for specifying common data shared with another PLC;

a receiving unit that receives the common-data specifying information from another PLC; and

a collating unit that collates the common-data specifying information stored in the storage unit with the common-data specifying information received by the receiving unit.

2. The PLC according to claim 1, wherein the collating unit performs the collation of the common-data specifying information when the distributed control system starts or restarts.

3. The PLC according to claim 1, wherein the common-data specifying information includes information on an address where the common-data is assigned in a frame used for communication of the distributed control system.

4. The PLC according to claim 1, wherein

the distributed control system is composed of a plurality of PLCs, and

the common-data specifying information includes identification information for identifying the plurality of PLCs.

5. A distributed control system comprising:

a plurality of PLCs for distributed control according to any one of claims 1 to 4 that are connected to one another,

wherein the plurality of PLCs are mutually cooperated with one another.

6. The distributed control system according to claim 5, wherein each of the PLCs includes a transmitting unit that transmits the common-data specifying information to another PLC.

7. The distributed control system according to claim 5,

wherein each of the PLCs is a safety PLC for ensuring safety of a control object connected to the corresponding PLC.

8. The distributed control system according to claim 5, wherein the common-data specifying information is input to each of the PLCs together with a program to be executed by the corresponding PLC.

9. The distributed control system according to claim 5, wherein the common-data specifying information items are associated with each other on a ladder diagram representing the content of programs to be executed by the PLCs.