Communication system for a control system over ethernet and IP networks

• US 20020194365A1
• Filed: 04/10/2002
• Published: 12/19/2002
• Est. Priority Date: 03/16/1998
• Status: Active Grant

• Current Assignee: Francois Jammes
• Original Assignee: Francois Jammes
• Inventors: Jammes, Francois
• Granted Patent: US 7,162,510 B2
• Time in Patent Office: Days
• US Class Current: 709/237
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 2012/40228 Modbus
• CPC Class Codes: H04L 2012/4026 Bus for use in automation systems
• CPC Class Codes: H04L 41/00 Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/13 in a LAN segment, e.g. ring or bus
• CPC Class Codes: H04L 47/2433 Allocation of priorities to traffic types
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04L 67/51 Discovery or management thereof, e.g. service location protocol [SLP] or web services
• CPC Class Codes: H04L 67/55 Push-based network services
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A communication system is provided for communication within a control system. The communication system has a plurality of simple devices connected to an intra-level communications network, each simple device being adapted to directly exchange data with the other simple devices. The communications system also has at least one intelligent device connected to the intra-level communications network, each intelligent device being adapted to directly exchange data with each simple device on the intra-level communications networks. The communication system can have a plurality of intra-level communications networks. The intra-level communications networks can be directly be connected by an intra-level core connector or by an inter-level core connector through an inter-level network of the intelligent devices.

Claims

1. A method of communicating within a connectionless network having a plurality of devices operably connected via Ethernet, the method comprising the steps of:

publishing a data frame via user datagram protocol (UDP) and internet protocol (IP), the data frame being published by the publisher device;

associating a refreshment status with the published data frame, the refreshment status corresponding to the time of publication of the data frame onto the network;

receiving the published data frame, the data frame being received by the subscriber device; and

,

providing a promptness status responsive to the subscriber device, the promptness status being associated with the received data frame and indicative of the time of receipt of the published data wherein the subscriber device being capable of determining the duration of the published data frame.

2. The method of claim 1 further comprising:

broadcasting a network clock signal to the plurality of devices on the connectionless network wherein the refreshment status and the promptness status are responsive to the network clock.

3. The method of claim 2 further comprising:

synchronizing a local clock of each of the plurality of devices with the broadcasted network clock signal.

4. The method of claim 1 wherein the publishing of the data frame comprises IP multicasting for transmitting the data frame to a predetermined group of network devices selected from the plurality of network devices.

5. The method of claim 4 further comprising:

dynamically defining the predetermined group of network devices for receiving the data frame via IP multicasting.

6. The method of claim 1 wherein the publishing of the data frame is responsive to an event.

7. The method of claim 3 wherein the publishing of the data frame is cyclical, the cyclical publication of the data frame being responsive to the local clock of the publisher device.

8. The method of claim 1 wherein configuring the device for system communication comprises:

providing a device logical identifier;

providing a data reference;

providing timing information; and

,

providing an IP multicast address.

9. The method of claim 1 wherein the data frame comprises:

an A_PDU header;

a fault indicator for indicating the occurrence of a fault in the publisher device;

an accelerator for determining the destination of the data frame;

a data management field for indicating the type of data reference utilized in the data frame; and

,

a data value field.

10. The method of claim 1 wherein the data frame is published to only a single subscriber device on the connectionless network.

11. The method of claim 1 wherein the data frame is published via broadcasting to all devices on the network.

13. The method of communicating of claim 12 further comprising:

entering a network fallback mode in response to the refreshment status.

14. The method of communicating of claim 12 further comprising:

entering a network fallback mode in response to the promptness status.

15. The method of communicating of claim 12 wherein the predetermined time limit comprises:

a propagation delay associated with processing the data frame throughout the connectionless network; and

,

a connectionless network delay.

16. The method of claim 12 further comprising sychronizing a local clock of the publisher device with the network clock.

17. The method of claim 16 wherein the publishing of the data frame being cyclical, the cyclical publication of the data frame being responsive to the local clock of the publisher device..

18. The method of claim 12 wherein the publishing of the data frame being responsive to an event.

19. The method of claim 12 wherein the publishing of the data frame being via IP multicasting to a selected cluster of subscriber circuits.

12. A method of communicating within a connectionless network having a plurality of devices comprising at least a publisher device and a subscriber device, the method comprising the steps of:

broadcasting a network clock signal throughout the connectionless network;

publishing a data frame via user datagram protocol (UDP) and internet protocol (IP);

associating a refreshment status with the published data frame, the refreshment status corresponding to the time of publication of the data frame;

synchronizing the refreshment status with the network clock signal;

subscribing to the data frame wherein the subscriber device receives the published data frame; and

,

associating a promptness status with the published data frame, the promptness status being responsive to the subscriber device and corresponding to the time of receipt of the data frame by the subscriber device wherein the subscriber device being capable of determining whether the duration of the published data frame has exceeded a predetermined time limit.

20. The method of claim 20 wherein the publishing of the data frame being via broadcasting to all device on the connectionless network.