Transmission frame structure for control communication network of distributed control system for nuclear power plant

• US 20060007927A1
• Filed: 04/12/2005
• Published: 01/12/2006
• Est. Priority Date: 04/12/2004
• Status: Abandoned Application

• Current Assignee: Korea Electric Power Corporation (Government of South Korea)
• Original Assignee: Korea Electric Power Corporation (Government of South Korea)
• Inventors: Song, Sung Il, Lee, Sung Woo, Oh, Eung Se, Kim, Seok Gon, Gwak, Kwi Yil
• Application Number:
  US11/103,738
• Publication Number:
  US 20060007927A1
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 12/42 Loop networks

Abstract

A transmission frame structure for use in a control communication network allows all process control stations contained in the control communication network to share monitoring/control information received from a field communication network or an information communication network, and properly copes with faulty operations of channels (i.e., ring-shaped lines) or process control stations for use in the control communication network. The transmission frame structure of a control communication network for use in a nuclear-power-plant distributed control system which broadcasts data received from a node having transmission authority to all nodes via a bypass line, and allows a ring accelerator to detour the data and to isolate an erroneous station from normal stations, includes a transmission frame. The transmission frame includes: a destination address for performing the broadcasting operation; a source address for recording a source node address (ID) therein; a type/length field for classifying frames into a control data frame and a network management event frame; a network management (NM_TYPE) field which is valid only when it is designated by type/length field, and performs different roles according to network management event frame types; a Seq&Ver field for including the number of transmissions of a data frame and frame upgrade version information; a NS_ID field for recording number information of a node equal to the next token reception node, and being used when one station transmits a token to the next station; a data field having a predetermined maximum size of 1 kbyte, for including not only general control information according to a value of the type/length field, but also 7 event frames such as a token frame; and a CRC (Cyclic Redundancy Code) field for inspecting the presence or absence of a CRC error, whereby the transmission frame operates the communication network, solves a malfunction or error of the communication network, and recovers the communication network.

Claims

1. A transmission frame structure of a control communication network for use in a nuclear-power-plant distributed control system which broadcasts data received from a node having transmission authority to all nodes via bypass line, and allows a ring accelerator to pass the data by a roundabout way and to isolate an erroneous station from normal stations, comprising:

a transmission frame including;

a destination address for performing the broadcasting operation;

a source address for recording a source node address (ID) therein;

a type/length field for classifying frames into a control data frame and a network management even frame;

a network management (NM_TYPE) field which is valid only when it is designated by type/length field, and performs different roles according to network management event frame types;

a Seq&

Ver field for including the number of transmissions of a data frame and frame upgrade version information;

a NS_ID field for recording number information of a node equal to the next token reception node, and being used when one station transmits a token to the next station;

a data field having predetermined maximum size 1 kbyte, for including not only general control information according to a value of the type/length field, but also 7 event frames (i.e., NM_TOKEN_FRAME, NM_DUAL_CH_CHECK_FRAME, NM_DUAL_CH_READY_FRAME, NM_NM_LINK_CHECK_FRAME, NM_NM_NODE_FAIL_FRAME, NM_NODE_CHECK_FRAME, and NM_TX_MODE_FRAME frames) such as a token frame; and

a CRC (Cyclic Redundancy Code) field for inspecting the presence or absence of a CRC error,

whereby the transmission frame operates the communication network, solves a malfunction of the communication network, and recovers the communication network.

2. The transmission frame structure according to claim 1, wherein the transmission frame structure performs data communication using the NM_TYPE field including the 7 event frames for network management, the type/length field for discriminating between the data frame and the event frames, and the NS_ID field including token scheduling information.

3. The transmission frame structure according claim 1, wherein the event frames contained in the NM_TYPE field controls the type/length field to indicate a token frame without using an additional token transmission, and then perform an event control operation.

4. The transmission frame structure according to claim 1, wherein the NM_DUAL_CH_CHECK_FRAME frame indicative of a backup channel check frame determines the presence or absence of soundness of a channel to be switched, if a current channel is in an abnormal state.

5. The transmission frame structure according to claim 1, wherein the NM_DUAL_CH_READY_FRAME frame informs general nodes of a preparation state of communication switching to a backup channel, if a main channel is in an abnormal state.

6. The transmission frame structure according to claim 1, wherein the NM_LINK_CHECK_FRAME frame periodically determines whether a backup line (i.e., a link) indicative of a communication network backup channel is alive whenever it receives a token predetermined reception times.

7. The transmission frame structure according to claim 1, wherein the NM_NODE_FAIL_FRAME frame transmits new token scheduling information to all nodes when a node is isolated or encounters a malfunction or error, and thus indicates an address of an abnormal node.

8. The transmission frame structure according to claim 1, wherein the NM_NODE_CHECK_FRAME frame periodically determines whether a node isolated by a malfunction or error returns to a normal state, such that it is re-included in the comminication network when the node recovers from the malfunction or error, and is then assigned transmission authority.

9. The transmission frame structure according to claim 1, wherein the NM_TX_MODE_FRAME frame releases reception mode maintenance of aN erroneous node when the erroneous node is restored to a normal state, such that the node can perform data transmission (Tx) upon receiving the token.

10. The transmission frame structure according to claim 2, wherein the event frames contained in the NM_TYPE field controls the type/length field to indicate a token frame without using an additional token transmission, and then perform an event control operation.