JP5717683B2 - Plant communication control equipment - Google Patents

Description

  The present invention relates to a communication control device for a plant for a power plant, for example, which transmits a signal by Ethernet (registered trademark) communication.

  For example, Ethernet communication may be used in plant control sites such as turbines and boilers at power plants, but the signals used for Ethernet communication may interfere with plant operations such as plant operation and shutdown. Since it is limited to the control of no display signal or the like, it is a top priority to prevent an alarm in Ethernet communication from being mistaken for a plant accident.

  However, in Ethernet communication, due to characteristics, when each terminal transmits at the same time, a collision occurs on the network, and when a collision occurs, a communication abnormality occurs in which transmission processing is canceled due to excessive collision.

  In a local area network, due to a lack of reception buffers, create a retransmission count change frame requesting that the number of retransmissions be increased in order to avoid data retransmission failure several times, and change the number of retransmissions sent to all communication partners. Japanese Patent Application Laid-Open No. 2004-228561 has a notification unit and analyzes the received retransmission count change notification frame and changes the value of the retransmission count area on the data transmission side.

JP-A-5-292097

  However, what is disclosed in Patent Document 1 is a system that detects and retransmits a reception buffer shortage in general data transmission, and does not use plant control but also detects and deals with data collisions. Not a thing.

  An object of the present invention is to eliminate the adverse effect of data collision in Ethernet communication on plant control. Even when a collision occurs, the number of retries, the transmission time, or the transmission interval are changed. By implementing this, the number of collisions per unit time is minimized and Ethernet communication abnormalities are reduced.

A plant communication control device according to the present invention includes a communication unit and a control unit, and connects a plurality of control devices that perform communication control of the plant with a local area network (LAN) cable, and performs Ethernet communication between the control devices. In the plant communication control apparatus, the communication unit detects the number of collisions between Ethernet communications, and increases or decreases the number of Ethernet communication retries from the control unit according to a command from the control unit based on the number of collisions within a predetermined time. It is what I did.

The plant communication control device according to the present invention includes a communication unit and a control unit, and a plurality of control devices that perform communication control of the plant are connected by a LAN cable, and the plant communication control performs Ethernet communication between the control devices. In the apparatus, when the number of collisions between Ethernet communications is detected by the communication unit and the number of collisions within a predetermined time increases, the count value of the transmission counter of the communication unit is changed according to a command from the control unit to perform Ethernet communication. The transmission time is shortened.

The plant communication control device according to the present invention includes a communication unit and a control unit, and a plurality of control devices that perform communication control of the plant are connected by a LAN cable, and the plant communication control performs Ethernet communication between the control devices. In the apparatus, when the number of collisions between Ethernet communications is detected by the communication unit and the number of collisions within a predetermined time increases, the transmission counter initialization value of the communication unit is changed according to a command from the control unit, and the Ethernet communication The transmission interval is shortened.

The plant communication control device according to the present invention includes a communication unit and a control unit, and a plurality of control devices that perform communication control of the plant are connected by a LAN cable, and the plant communication control performs Ethernet communication between the control devices. In the apparatus, when the number of collisions between Ethernet communications is detected by the communication unit , and the number of times of collision is increased while increasing or decreasing the number of Ethernet communication retries based on the number of collisions within a predetermined time, By changing the count value of the transmission counter of the communication unit, the transmission time of Ethernet communication is shortened.

The plant communication control device according to the present invention includes a communication unit and a control unit, and a plurality of control devices that perform communication control of the plant are connected by a LAN cable, and the plant communication control performs Ethernet communication between the control devices. In the apparatus, the number of collisions between Ethernet communications is detected by the communication unit , the number of Ethernet communication retries is increased or decreased based on the number of collisions within a fixed time, and when the number of collisions increases, according to a command from the control unit, The transmission counter initialization value of the communication unit is changed to shorten the transmission interval of Ethernet communication.

The plant communication control device according to the present invention includes a communication unit and a control unit, and a plurality of control devices that perform communication control of the plant are connected by a LAN cable, and the plant communication control performs Ethernet communication between the control devices. In the apparatus, the number of collisions between Ethernet communications is detected by the communication unit , the number of Ethernet communication retries is increased or decreased based on the number of collisions within a fixed time, and when the number of collisions increases, according to a command from the control unit, The transmission counter and transmission counter initialization value of the communication unit are changed to shorten the transmission time and transmission interval of Ethernet communication.

  According to the present invention, in Ethernet communication, the reliability of overall plant control can be improved by reducing the number of Ethernet communication collisions and suppressing Ethernet communication abnormality.

It is a block diagram which shows the communication control apparatus of the plant which concerns on this invention. It is a flowchart explaining the operation | movement of Embodiment 1 of this invention. It is a flowchart explaining the operation | movement of Embodiment 2 of this invention. It is a flowchart explaining the operation | movement of Embodiment 3 of this invention. It is a flowchart explaining operation | movement of Embodiment 4 of this invention. It is a flowchart explaining the operation | movement of Embodiment 5 of this invention. It is a flowchart explaining operation | movement of Embodiment 6 of this invention.

Embodiment 1 FIG.
FIG. 1 shows a communication control device in which n control devices according to the present invention are connected by a LAN cable. For example, in a power plant, a control device 13 for a turbine, a control device 23 for a waste heat recovery boiler, and sequence control are shown. 1 shows a network in which a control device 33 for electric power and a control device n3 for electric auxiliary equipment are connected by a LAN cable 10. The control device referred to here does not relate to the operation of the plant itself, but refers to a device that controls a display device or the like necessary for the operation. The control devices 13, 23, 33, and n3 are connected to the LAN cable 10 by the transceivers 11, 21, 31, and n1 through the LAN cables 12, 22, 32, and n2, respectively. Since the configurations of the respective control devices are the same, the first control device 13 will be described below, and the other control devices are denoted by the reference symbol “n” representing the nth.

The control device 13 is connected to the transceiver 11 via a LAN cable 12 and includes a communication unit 14 and a control unit 15 connected thereto. The control device 13 transmits and receives signals to and from another control device n3 via the LAN cable 10. As for the signal transmission result, the communication unit 14 in the control device 13 detects the completion of transmission or collision, returns to the state before transmission, and returns to the collision count signal 16 (
The number of times when the transmission processing is stopped due to excessive collisions) is detected and transmitted to the control unit 15. The control unit 15 returns the retransmission number signal 17 to the communication unit 14, and the communication unit 14 performs retransmission (retry) processing.

The operations of the communication unit 14 and the control unit 15 will be described with reference to the flowchart shown in FIG. The control unit 15 counts the number of collisions by the collision number signal 16 transmitted from the communication unit 14, and when the count value of the collision number counter exceeds a threshold value X within a certain time (step S201), the Ethernet communication retry is performed. The communication unit 14 is instructed by the retransmission number signal 17 so as to increase the number m of transmissions (step S202). The retry transmission count is set to an upper limit of “16 times” because the general-purpose general maximum value is “16 times” (step S203). On the other hand, when the count value of the collision number counter is less than a certain threshold Y within a certain time (step S204)
Then, the number m of retry transmissions of Ethernet communication is decreased (step S205). The minimum value is set to “3 times” in consideration of reliability and controllability in the plant control apparatus for power plants (step S206).

  In response to the processing result of the control unit 15 as described above, the communication unit 14 performs communication. When the count value of the transmission counter becomes 0 or less (step S207), a transmission process (retry process) is performed (step S208), the transmission counter is initialized, and the process ends (step S209). If the count value of the transmission counter is not less than 0, the transmission counter is decremented by 1 (step S210), and the process ends.

  As described above, according to the first embodiment, when the number of collisions per unit time increases, the number of retry transmissions is increased. Therefore, the number of subsequent collisions is reduced, communication abnormality of Ethernet communication is reduced, and the entire plant control is performed. Reliability can be improved.

Embodiment 2. FIG.
The operation of the control apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. The configuration of the control device and the transmission / reception operation between the control devices are the same as those in FIG. FIG. 3 is a flowchart showing operations of the communication unit 14 and the control unit 15 of the control device according to the present embodiment.

  When the count value of the transmission counter of the communication unit 14 is not less than or equal to 0 (step S301), the control unit 15 counts the number of collisions of the collision number signal 16 transmitted from the communication unit 14, and the count value of the collision number counter Exceeds a certain threshold value X within a certain time (step S302), the Ethernet communication transmission counter is subtracted, for example, (−2 to n + 1) at random (step S303) to shorten the communication time. The communication unit 14 performs transmission processing based on the retransmission number signal 17 (step S304), initializes a transmission counter (step S305), and ends the processing. If the number of collisions per unit time is smaller than the threshold value X, the transmission counter is decremented by 1 (step S306), and the process ends.

  By changing the transmission time of the Ethernet communication of the control device 13 in this process, the Ethernet communication timing with the other control device n3 can be shifted, the number of collisions can be reduced, and communication abnormality can be reduced.

Embodiment 3 FIG.
The operation of the control apparatus according to Embodiment 3 of the present invention will be described with reference to FIG. The configuration of the control device and the transmission / reception operation between the control devices are the same as those in FIG. FIG. 4 is a flowchart showing operations of the communication unit 14 and the control unit 15 of the control device according to the present embodiment.

  When the count value of the transmission counter becomes 0 or less (step S401), the communication unit 14 performs transmission processing (step S402), initializes the transmission counter (step S403), and ends the processing. When the count value of the collision number counter by the collision number signal 16 from the communication unit 14 exceeds a certain threshold value X within a certain time (step S404), the control unit 15 randomly sets a transmission initialization value for Ethernet communication. For example, it is set between (1 to n-1) (step S405). As a result, the transmission interval of the control device 13 is changed to shift the Ethernet communication timing with the other control device n3, thereby reducing the number of collisions. The transmission counter is decremented by 1 (step S406), and the process ends.

Embodiment 4 FIG.
The operation of the control apparatus according to Embodiment 4 of the present invention will be described with reference to FIG. The configuration of the control device and the transmission / reception operation between the control devices are the same as those in FIG. FIG. 5 is a flowchart showing operations of the communication unit 14 and the control unit 15 of the control device according to the present embodiment.

When the count value of the collision number counter exceeds the threshold value X within a certain time by the collision number signal 16 transmitted from the communication unit 14 to the control unit 15 (step S501),
(A) When the count value of the transmission counter value is 0 or less (step S502), the Ethernet communication transmission process is performed (step S503), and the transmission counter initialization value is set to k times the normal value n (k is a constant). In order to avoid collision, the next transmission time interval is lengthened.
(B) If the count value of the transmission counter value is not less than or equal to 0 (step S502), by increasing or changing the transmission counter subtraction count of Ethernet communication randomly between (−1 to −n + 1) (step S505), the control device 13 and the Ethernet control timing of the other control device n3 are shifted. Other processes (step S506) to (step S509) are the same processes as steps S207 to S210 of the first embodiment.

  According to the above (a) and (b), the collision avoidance of the other control device is implemented, the total number of collisions is reduced, and the Ethernet communication abnormality is reduced.

Embodiment 5 FIG.
The operation of the control apparatus according to Embodiment 5 of the present invention will be described with reference to FIG. The configuration of the control device and the transmission / reception operation between the control devices are the same as those in FIG. FIG. 6 is a flowchart showing operations of the communication unit 14 and the control unit 15 of the control device according to the present embodiment.

  When the count value of the collision number counter transmitted from the communication unit 14 to the control unit 15 exceeds a certain threshold value X within a predetermined time (step S601), the retry transmission number m of Ethernet communication is increased (step S602). The retry transmission count is set to an upper limit setting of “16 times” since the general-purpose general maximum value is “16 times” (step S603). On the other hand, if the count value of the collision number counter is less than a certain threshold value Y within a certain time (step S604), the retry transmission number m of Ethernet communication is decreased (step S605). The minimum number of retries is set to “3 times” in consideration of reliability and controllability in the plant control apparatus for power plants (step S606).

If the count value of the transmission counter is not less than 0 and the count value of the collision counter transmitted to the control unit 15 exceeds a certain threshold value X within a certain time (step S607), the transmission counter subtraction count of Ethernet communication Is increased or varied randomly between (−1 to −n + 1) (step S608), thereby shifting the Ethernet communication timing between the control device 13 and the other control device n3). The other processes (step S609) to (step S612) are the same processes as steps S207 to S210 of the first embodiment.

  As a result, collision avoidance with other control devices is implemented, the total number of collisions is reduced, and Ethernet communication abnormalities are reduced.

Embodiment 6 FIG.
The operation of the control apparatus according to Embodiment 6 of the present invention will be described with reference to FIG. The configuration of the control device and the transmission / reception operation between the control devices are the same as those in FIG. FIG. 7 is a flowchart showing operations of the communication unit 14 and the control unit 15 of the control device according to the present embodiment.

When the count value of the collision counter transmitted from the communication unit 14 to the control unit 15 exceeds a certain threshold value X within a certain time (step S701), the retry transmission number m of Ethernet communication is increased (step S702). The retry transmission count is set to an upper limit of “16 times” because the general-purpose general maximum value is “16 times” (step S703). On the other hand, when the count value of the collision number counter is less than a certain threshold Y within a certain time (step S04).
) The retry transmission number m of the Ethernet communication is decreased (step S705). The minimum value is set to “3 times” in consideration of the reliability and controllability of the plant control device for the power plant (step S706).

When the count value of the collision number counter transmitted from the communication unit 14 to the control unit 15 exceeds a certain threshold value X within a certain time (step S707),
(A) When the count value of the transmission counter is 0 or less (step S708), the transmission processing of Ethernet communication is performed (step S709), and the transmission counter initialization value is changed to k times the normal value n (k is a constant). (Step S710), the next transmission time interval is lengthened to avoid a collision.
(B) When the count value of the transmission counter is not less than or equal to 0 (step S710), the control device 13 can increase or fluctuate the transmission counter subtraction count of Ethernet communication randomly between (−1 to −n + 1) (step S711). And the other communication device n3 and the Ethernet communication timing are shifted. Other processes (step S712) to (step S715) are the same processes as steps S207 to S210 of the first embodiment.

  By implementing the above (a) and (b), the collision avoidance of other control devices is implemented, and the total number of collisions is reduced, leading to a reduction in Ethernet communication abnormality.

10 LAN cable,
11, 21, 31, n1 transceiver,
12, 22, 32, n2 LAN cable,
13, 23, 33, n3 controller,
14, 24, 34, n4 communication unit,
15, 25, 35, n5 control unit,
16, 26, 36, n6 collision frequency signal,
17, 27, 37, n7 Retransmission count signal.

Claims (6)

In a plant communication control device that has a communication unit and a control unit and controls a plurality of control devices for controlling plant communication with LAN cables, and performs Ethernet communication between the control devices, the number of collisions between Ethernet communications by the communication unit And a communication control device for a plant characterized in that the number of retries for Ethernet communication from the control device is increased or decreased by a command from the control unit based on the number of collisions within a predetermined time. In a plant communication control device that has a communication unit and a control unit and controls a plurality of control devices for controlling plant communication with LAN cables, and performs Ethernet communication between the control devices, the number of collisions between Ethernet communications by the communication unit When the number of collisions within a predetermined time is detected, the control unit command changes the count value of the transmission counter of the communication unit to shorten the transmission time of the Ethernet communication. Communication control device. In a plant communication control device that has a communication unit and a control unit and controls a plurality of control devices for controlling plant communication with LAN cables, and performs Ethernet communication between the control devices, the number of collisions between Ethernet communications by the communication unit detects if the number of collisions within a predetermined time is increased, by a command from the control unit changes the transmission counter initialization value of the communication unit, the plant, characterized by shortening the transmission interval of the Ethernet communication Communication control device. In a plant communication control device that has a communication unit and a control unit and controls a plurality of control devices for controlling plant communication with LAN cables, and performs Ethernet communication between the control devices, the number of collisions between Ethernet communications by the communication unit When the number of times of collision is increased and the number of times of collision is increased based on the number of collisions within a certain time, the count value of the transmission counter of the communication unit is changed according to a command from the control unit, and the Ethernet A communication control device for a plant, characterized by shortening the transmission time of communication. In a plant communication control device that has a communication unit and a control unit and controls a plurality of control devices for controlling plant communication with LAN cables, and performs Ethernet communication between the control devices, the number of collisions between Ethernet communications by the communication unit , And increase / decrease the number of Ethernet communication retries based on the number of collisions within a certain time, and when the number of collisions increases, according to the command of the control unit, change the transmission counter initialization value of the communication unit, A plant communication control apparatus characterized by shortening the transmission interval of Ethernet communication. In a plant communication control device that has a communication unit and a control unit and controls a plurality of control devices for controlling plant communication with LAN cables, and performs Ethernet communication between the control devices, the number of collisions between Ethernet communications by the communication unit When the number of collisions increases, the counter value of the transmission counter of the communication unit and the initial value of the transmission counter are A communication control apparatus for a plant, characterized in that the transmission value and the transmission interval of Ethernet communication are shortened by changing the conversion value.

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