Arbitration method for a communication network

• US 5,960,174 A
• Filed: 12/20/1996
• Issued: 09/28/1999
• Est. Priority Date: 12/20/1996
• Status: Expired due to Fees

• Current Assignee: Square D Company (Schneider Electric SE)
• Original Assignee: Square D Company (Schneider Electric SE)
• Inventors: Dew, Larry A.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): DINH, KHANH Q
• Application Number:
  US08/771,621
• Time in Patent Office: 1,012 Days
• Field of Search: 395/200.38, 395/200.41, 395/200.4, 395/110, 395/728, 395/288, 395/280, 395/287, 395/325, 395/869
• US Class Current: 709/208
• CPC Class Codes: H04L 12/40143 involving priority mechanisms hybrid switching fabrics H04L12/6402; intermediate storage or scheduling H04L49/90; time-division multiplex systems H04J3/00
• CPC Class Codes: H04L 12/40202 by using a plurality of master stations
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling

Abstract

A communications network is used to couple weld controllers and different operator interface units together, regardless of their data structures. An arbitration system provides a means for one operator interface unit to communicate to a selected weld controller at a given period of time. The operator interface units have one of three modes of operation. These include database master, primary master, and secondary master. During setup of the communications network, the master devices are assigned a physical address that defines the its type and priority within the network. The database master is the only device which can automatically download data to a weld controller. It has the highest priority as a network arbiter. The primary master will act as the network abitrator in the absence of a database master. A secondary master must listen for an access grant from the current network arbiter, before initiating a message packet on the network. When no database or primary device exists on a network, the secondary device with the highest priority, as defined by its address during startup, assumes the role of network arbitrator.

Claims

1. A system communications network comprising:

A. a plurality of master control devices coupled to said communications network, each of said master control devices having an application program for controlling communications on said network, some of said master controls having dissimilar data structures;

B. a plurality of slave devices coupled to said communications network, some of said slave devices having dissimilar data structures;

C. a network arbiter for controlling network traffic of the communications network at a given period of time, said network arbiter operatively chosen from one of said master control devices;

D. at least one of said master control devices functioning as a master database device for the network;

E. wherein said network arbiter is chosen from said master control devices on a basis of an arbitration priority assigned to said master control devices, with said master database device having the highest priority;

F. wherein each of said master control devices, through its application program, monitors the network for network traffic, and assumes control of the network as network arbiter if no master control device with a higher priority is active on the network; and

G. wherein said master database device will always attempt to assume control of the network as network arbiter when said master database device requires control.

2. The system communications network of claim 1 wherein said master database device includes a system database system, said data base for storing data associated with each master control and slave device coupled to the network.

3. The system communications network of claim 2 wherein one of said master control devices is a primary master control device, wherein said primary master control device will always attempt to assume control of the network as network arbiter in the absence of a master database device, and wherein said primary master control device will lose control as arbiter when said master database device reattaches to the network.

4. The system communications network of claim 3 wherein one of said master control devices is a secondary master control device, wherein said secondary master control device will assume control of the network as network arbiter by an access grant from a current network arbiter.

5. The system communications network of claim 4 wherein a secondary master control device with the highest assigned arbitration priority will assume control of the network as network arbiter in the absence of the master database device and primary master control device.

6. The system communications network of claim 5 wherein only one of said master control devices will assume control of the network as network arbiter at any one period of time, and wherein during said period of time said master control device for uploading and downloading data to a selected slave device.

7. The system communications network of claim 6 wherein said master control device as network arbiter, for uploading and downloading data to another selected master control device during said period of time.

8. The system communications network of claim 7 wherein said master database device, as network arbiter, can broadcast a message to all slave devices at the same time.

9. The system communications network of claim 7 wherein said master database device, as network arbiter, can broadcast a message to all other master devices at the same time.

10. A system communications network for coupling a plurality of weld controllers, said network comprising:

A. a plurality of operator interface units coupled to said communications network, each of said operator interface units having an application program for controlling communications on said network, and a program for sending data having dissimilar data structures, said data for monitoring and controlling selected ones of said weld controllers;

B. a network arbiter for controlling network traffic of the communications network at a given period of time, said network arbiter operatively chosen from one of said operator interface units;

C. at least one of said operator interface units functioning as a master database device for the network;

D. wherein said network arbiter is chosen from said operator interface units on a basis of an arbitration priority assigned to said operator interface units, with said master database device having the highest priority;

E. wherein each of said operator interface unit, through its application program, monitors the network for network traffic, and assumes control of the network as network arbiter if no operator interface unit with a higher priority is active on the network; and

G. wherein said master database device will always attempt to assume control of the network as network arbiter when said master database device requires control.

11. The system communications network of claim 10 wherein said master database device includes a system database system, said database for storing data associated with each operator interface unit and weld controller coupled to the network.

12. The system communications network of claim 11 wherein one of said operator interface units functions as a primary master control device, wherein said primary master control device will always attempt to assume control of the network as network arbiter in the absence of a master database device, and wherein said primary master control device will lose control as arbiter when said master database device reattaches to the network.

13. The system communications network of claim 12 wherein one of said operator interface units functions as a secondary master control device, wherein said secondary master control device will assume control of the network as network arbiter by an access grant from a current network arbiter.

14. The system communications network of claim 13 wherein a secondary master control device with the highest arbitration priority will assume control of the network as network arbiter in the absence of the master database device and primary master control device.

15. The system communications network of claim 14 wherein only one of said operator interface units will assume control of the network as network arbiter at any one period of time, and wherein during said period of time said operator interface unit for uploading and downloading data to a selected weld controller.

16. The system communications network of claim 15 wherein said operator interface unit functioning as the master database device, for uploading and downloading data to another selected operator interface unit during said period of time.

17. The system communications network of claim 16 wherein said operator interface unit functioning as the master database device can broadcast a message to all weld controllers at the same time.

18. The system communications network of claim 17 wherein said operator interface unit functioning as the master database device as network arbiter can broadcast a message to all other operator interface units at the same time.