JP3992895B2 - Transmission system having abnormality monitoring function, terminal device having abnormality monitoring function, and recording medium recording processing program in terminal device having abnormality monitoring function - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transmission system that performs socket communication between terminal devices that implement the TCP / IP (Transmission Control Protocol / Internet Protocol) protocol, and in particular, by monitoring monitoring data of a certain period for each socket to monitor abnormalities. The present invention relates to a transmission system having an abnormality monitoring function capable of detecting an abnormality for each socket, a terminal device having an abnormality monitoring function, and a recording medium recording a processing program in the terminal device having the abnormality monitoring function.
[0002]
[Prior art]
Conventionally, socket communication is performed by connecting terminal devices such as a personal computer, a PLC (Programmable Logic Controller), and a workstation via a LAN (Local Area Network) such as Ethernet.
[0003]
As an example of such communication, a general transmission system conventionally performed between a pump station and a treatment plant in a water supply business will be described with reference to FIG.
[0004]
As shown in FIG. 4, the conventional transmission system 101 includes a PLC 104 connected to the monitoring device 103 of the treatment plant 102, a PLC 107 connected to the pump 106 of the pump plant 105, and the treatment plant 102 and the pump plant 105. And a transmission line 108 for connecting the two.
[0005]
Here, the PLCs 104 and 107 implement the TCP / IP protocol, and transmit and receive transmission data by socket communication. There are a plurality of sockets, and sockets for transmitting digital data, analog data, pulse data, digital output, set value output and the like are prepared.
[0006]
Further, the transmission path 108 is a LAN transmission path such as Ethernet, and in particular, in the case of Ethernet, the PLCs 104 and 107 are connected via a transceiver cable, a transceiver, and an Ethernet coaxial cable. Moreover, it may be connected with the optical fiber cable installed in the sewer pipe through the ATM router.
[0007]
TCP transmission by this conventional transmission system will be described based on a flowchart.
[0008]
First, processing in the PLC 104 on the transmission side will be described based on the flowchart of FIG. On the transmitting side, first, a socket for transmitting transmission data among a plurality of sockets is actively opened, and the receiving side is requested to establish a connection (S501). At this time, if the corresponding socket on the receiving side is not passively opened, the connection is not established, so the process returns to step S501 to continue requesting the connection. If the socket on the receiving side is passively opened, the connection is established (S502) ). After the connection is established, if there is transmission data such as the operation instruction of the pump by the operator and the operation status of each device, it can be transmitted at any time. Therefore, it is determined whether or not transmission data is input by the operator (S503). When transmission data is input, the transmission data is transmitted (S504). Then, when it is determined in step S503 that no transmission data is input, or when transmission data input in step S504 is transmitted, it is determined whether or not to continue the connection (S505). Here, when the connection is terminated, the socket is closed (S506), the transmission is terminated, and when the connection is continuously established, the process returns to step S503 to continue the transmission.
[0009]
Next, processing in the PLC 107 on the receiving side will be described based on the flowchart of FIG. The receiving side first passively opens a socket to which data is transmitted, and requests the PLC 104 on the transmitting side to establish a connection (S601). At this time, if the transmission side is not actively opened, the connection is not established, so the process returns to step S601 to continue requesting connection establishment, and when the transmission side is actively opened, the connection is established (S602). When the connection is established, it is determined whether transmission data is transmitted (S603). When transmission data is transmitted, the transmission data is received (S604). When it is determined in step S603 that transmission data has not been transmitted, or when transmission data transmitted in step S604 is received, it is determined whether or not to continue the connection (S605), and the connection is terminated. If so, close the socket (S606) to end the transmission, and if the connection is to be established, return to step S603 to continue receiving the transmission data.
[0010]
[Problems to be solved by the invention]
However, in the above-described conventional transmission system, for example, when an abnormality such as a cable cut on the transmission line or a power failure of the terminal device occurs, the transmission data cannot be transmitted by the PLC 104 on the transmission side. Even the PLC 107 cannot receive the transmission data.
[0011]
However, in the transmission by the TCP / IP protocol, once the connection is normally established in the transmission by the TCP / IP protocol even though the transmission data cannot be transmitted due to the abnormality, the connection remains established and is disconnected. It never happened. Therefore, the PLCs 104 and 107 cannot detect an abnormality and fall into a state where transmission is performed normally. In particular, since the application software of the PLCs 104 and 107 is judged to be normal, the abnormality could not be detected. Therefore, when this state occurs, the operator cannot notice any abnormality until the transmission data is actually transmitted, and there has been a problem in terms of safety in the treatment facility in the water supply business. For example, in communication between the pump station 105 at a remote location and the monitoring device 103 of the treatment plant 102, TCP / IP protocol transmission is often used when transmitting an operation signal of a device such as a pump. The operation signal is generated when an operator inputs a command to the monitoring device 103. However, the operator may not operate the device for a long time such as one day, and at this time, an abnormality will be noticed only when the operator actually operates the device after a long time has passed since the failure. If the operation at this time was an urgent operation that would cause the pump to stop urgently, an abnormality was discovered when the operation was performed, such as water outage or suspension of water supply, flooding of rainwater, flooding of the treatment plant, etc. There was a problem of causing a serious situation.
[0012]
Furthermore, the PLCs 104 and 107 may be in a non-responsive state where they do not operate. In this case, a mechanism for recovering the PLC 104 and 107 has not been established.
[0013]
As another method for monitoring an abnormality on the line, a method using a ping command of the Internet Control Message Protocol ICMP (Internet Control Message Protocol) can be considered. This ping command is a command for verifying whether communication is normally performed in ICMP.
[0014]
In this ping command, an echo request message is created and transmitted from the PLC 104 on the transmission side, and when the PLC 107 on the reception side receives the message, it sends back an echo reply message. If this echo reply message can be received by the PLC 104 on the transmission side, it can be confirmed that there is no failure on the line.
[0015]
However, in this case, a dedicated socket for monitoring the line failure is provided to monitor the line failure, so if a failure occurs that makes all the sockets abnormal, this ping command is certainly used. However, when an abnormality occurs only in a socket other than the monitoring socket, the abnormality using the ping command cannot be detected.
[0016]
Also, a method of monitoring a line by transmitting fixed-cycle data using the UDP protocol is often used. Even in this method, a monitoring UDP socket is provided to monitor an abnormality of the line. Even if an abnormality has occurred in the socket, the abnormality of the TCP socket could not be detected if the UDP socket was normally transmitted.
[0017]
Therefore, even if the ping command is used or the UDP protocol is used, an abnormality can be detected if a failure occurs in the entire line, but the abnormality is detected only in a socket other than the line monitoring socket. When it occurs, there is a problem that the abnormality cannot be detected.
[0018]
Conversely, if a line monitoring socket is provided, if an abnormality occurs in the line monitoring socket, all sockets will be stopped. There was also the problem of being stopped.
[0019]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an abnormality monitoring capable of detecting an abnormality for each socket by transmitting monitoring data of a certain period for each socket and monitoring a transmission line. It is an object of the present invention to provide a transmission system having a function, a terminal device having an abnormality monitoring function, and a recording medium recording a processing program in the terminal device having an abnormality monitoring function.
[0020]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 is a case where terminal devices mounted with the TCP / IP protocol are connected by a LAN and transmission / reception of transmission data is performed between the terminal devices by socket communication. A transmission system having an abnormality monitoring function for monitoring an abnormality, wherein the transmission data and monitoring data transmitted at a constant cycle for monitoring the abnormality are transmitted for each socket, and the monitoring data is transmitted for a certain period of time. Socket that could not be sent when it could not be sent only A first terminal device that is initialized after closing, a transmission line for transmitting the transmission data and the monitoring data transmitted by the first terminal device, and the transmission data transmitted by the transmission line And the monitoring data for each socket, and when the monitoring data is not received for a certain period of time, the socket that was not received only And a second terminal device that is initialized after closing.
[0021]
According to the first aspect of the present invention, when the monitoring data cannot be transmitted / received for a certain period of time, it is determined that an abnormality has occurred and the corresponding socket is closed and initialized, so that it is not noticed that the abnormality has occurred. It is possible to prevent the connection from being established, and to detect a line abnormality promptly.
[0022]
Also, because monitoring data is sent and received for each socket to monitor each socket, there is no need to provide a dedicated socket for monitoring line failures, and only failures that cause all lines to become abnormal In addition, even when a failure occurs in which only one socket becomes abnormal, the abnormality can be detected. Furthermore, even if an abnormality occurs in one socket, it is no longer necessary to stop other normally transmitting sockets.
[0023]
The invention according to claim 2 is a terminal equipped with an abnormality monitoring function that implements the TCP / IP protocol and monitors an abnormality when transmitting / receiving transmission data by socket communication with other terminal devices connected by a LAN. When transmitting the transmission data to the other terminal device, the transmission data is transmitted, and monitoring data for monitoring an abnormality is transmitted for each socket at a certain period, and the monitoring data is transmitted. A socket that could not be sent if it could not be sent for a certain period of time only When the transmission data is received from the other terminal device, the transmission data is received and the monitoring data transmitted from the other terminal device at a certain period is received for each socket. When the monitoring data has not been received for a certain period of time, the socket that has not been received only It is characterized by initializing after closing.
[0024]
According to the second aspect of the present invention, it is possible to prevent the connection from being established without noticing that an abnormality has occurred, and to detect a line abnormality promptly.
[0025]
In addition, it is not necessary to provide a dedicated socket for monitoring line failures, and not only when a failure occurs in all lines, but also when a failure occurs in only one socket. The abnormality can be detected. Furthermore, even if an abnormality occurs in one socket, it is no longer necessary to stop other normally transmitting sockets.
[0026]
The invention according to claim 3 is a terminal equipped with an abnormality monitoring function that implements the TCP / IP protocol and monitors an abnormality when transmitting / receiving transmission data by socket communication with other terminal devices connected by a LAN. A recording medium recording a processing program in a device, wherein when transmitting the transmission data to the other terminal device, a process for transmitting the transmission data and a monitoring data for monitoring an abnormality are socketed at a constant cycle. Sockets that could not be sent when the monitoring data could not be sent for a certain period of time only And when the transmission data is received from the other terminal apparatus, the process of receiving the transmission data and the monitoring transmitted from the other terminal apparatus at a constant cycle. Processing for receiving data for each socket, and sockets that were not received when the monitoring data was not received for a certain period of time only And a process of initializing after closing.
[0027]
According to the third aspect of the invention, it is possible to prevent the connection from being established without noticing that an abnormality has occurred, and to detect a line abnormality promptly.
[0028]
In addition, it is not necessary to provide a dedicated socket for monitoring line failures, and not only when a failure occurs in all lines, but also when a failure occurs in only one socket. The abnormality can be detected. Furthermore, even if an abnormality occurs in one socket, it is no longer necessary to stop other normally transmitting sockets.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a transmission system having an abnormality monitoring function according to the present invention will be described below with reference to the drawings.
[0030]
As shown in FIG. 1, a transmission system 1 having an abnormality monitoring function according to the present invention has a transmission in which a terminal device 2 on a transmission side and a terminal device 3 on a reception side are formed by a LAN (Local Area Network) such as Ethernet. Connected by road.
[0031]
The terminal device 2 on the transmission side is a computer on which a TCP / IP (Transmission Control Protocol / Internet Protocol) protocol such as a personal computer, a workstation, or a PLC (Programmable Logic Controller) is mounted, and can perform socket communication. In addition to transmitting transmission data via a LAN such as Ethernet, monitoring data is transmitted at a constant cycle for each socket. There are a plurality of sockets. For example, a socket for transmitting digital data, analog data, pulse data, digital output, set value output, etc. is prepared for transmission between a treatment plant and a pump station in a water supply business.
[0032]
Similarly, the terminal device 3 on the receiving side is a computer equipped with a TCP / IP protocol such as a personal computer, a workstation, or a PLC, and can perform socket communication and receive transmission data via a LAN such as Ethernet. At the same time, it receives monitoring data sent at regular intervals for each socket.
[0033]
The terminal devices 2 and 3 include a normal computer system including a CPU for performing various processes and a storage means for storing instructions for the processes, and each of the processes performed in the terminal devices 2 and 3 is performed. Instructions and timing constraints are held in the storage means, and are loaded into the CPU and executed as necessary.
[0034]
The transmission path connecting the terminal device 2 on the transmission side and the terminal device 3 on the reception side is constituted by a LAN. In particular, when the LAN is Ethernet, the terminal device 2 on the transmission side includes the transceiver cable 4 and the transceiver 5. The terminal device 3 is similarly connected to the Ethernet coaxial cable 6 via the transceiver cable 7 and the transceiver 8 on the receiving side. Further, by using an ATM router in place of the transceiver, an optical fiber cable may be used instead of the Ethernet coaxial cable as a transmission path.
[0035]
Next, data transmission and abnormality monitoring by the transmission system having the abnormality monitoring function of the present embodiment will be described based on the flowcharts of FIGS.
[0036]
First, processing in the terminal device 2 on the transmission side will be described based on the flowchart in FIG. On the transmission side, first, as an initialization process, a socket for transmitting data among a plurality of sockets is actively opened to request the reception side to establish a connection (S201). At this time, if the corresponding socket on the receiving side is not passively opened, the connection is not established, so the process returns to step S201 to continue requesting the connection, and when the socket on the receiving side is passively opened, the connection is established. (S202). After the connection is established, if there is transmission data such as the operation instruction of the pump by the operator and the operation status of each device, it can be transmitted at any time. Therefore, it is determined whether or not transmission data is input from the operator (S203). When transmission data is input, the transmission data is transmitted (S204). Then, it is confirmed whether or not the transmission data is transmitted to the terminal device 3 on the receiving side (S205), and when it is transmitted, it is determined whether or not the connection is to be established (S206). Here, when the connection is terminated, the socket is closed (S207), and the transmission is terminated.
[0037]
On the other hand, when transmission data has not yet been input at step S203, when transmission data has not been transmitted at step S205, or when connection is continued to be established at step S206, monitoring for monitoring that the line is normal. Send data. Since this monitoring data is transmitted at a constant period, for example, every 30 seconds, it is determined whether or not a certain time (for example, 30 seconds) corresponding to that period has elapsed (S208), and the certain time has elapsed. When it is done, monitoring data is transmitted (S209). Here, it is confirmed whether or not the monitoring data is transmitted to the terminal device 3 on the receiving side (S210). When the monitoring data is transmitted, the process returns to step S203 to determine the presence or absence of the next transmission data and continue the transmission. . On the other hand, when the monitoring data is not transmitted, the monitoring data is continuously transmitted for a certain time, for example, several minutes (S211), and when the monitoring data is transmitted during that time, it is determined that the monitoring data is normal, and the process returns to step S203 to continue the transmission. However, when monitoring data is not transmitted to the receiving side for a certain period of time, it is determined that an abnormality has occurred, the operator is notified of the occurrence of the abnormality, and the socket is closed (S213). Then, the process returns to step S201 again, the active open is performed, the reconnection is requested and initialized, and transmission data transmission is started again.
[0038]
As described above, in the transmission system having the abnormality monitoring function of the present invention, even if the monitoring data is continuously transmitted for a certain period of time, if it is not transmitted to the receiving side, it is determined that an abnormality has occurred and the line is closed once, Request reconnection.
[0039]
As a result, it is possible to prevent the connection from being established despite the occurrence of an abnormality, so that the abnormality can be detected promptly. It is possible to prevent a situation in which an abnormality is not noticed until input.
[0040]
Next, processing in the terminal device 3 on the receiving side will be described based on the flowchart of FIG. The receiving side first passively opens a socket to which transmission data is transmitted as an initialization process, and requests the transmitting side to establish a connection (S301). At this time, if the corresponding socket on the transmitting side is not actively opened, the connection is not established, so the process returns to step S301 to continue requesting the connection. When the corresponding socket on the transmitting side is actively opened, the connection is established. (S302). After the connection is established, if transmission data such as an operation instruction of the pump by the operator and the operation status of each device is input to the terminal device 2 on the transmission side, it is transmitted to the reception side as needed. Therefore, when the connection is established, it is determined whether or not transmission data is sent (S303), and when the transmission data is sent, the transmission data is received (S304). When the transmission data is received, it is determined whether or not the connection is continued (S305). When the connection is terminated, the socket is closed (S306) and the transmission is terminated.
[0041]
On the other hand, when transmission data is not sent in step S303, or when the connection is continued to be established in step S305, monitoring data transmitted from the terminal device 2 on the transmission side is monitored to monitor that the line is normal. Receive. Since the monitoring data is transmitted at a constant period, for example, at intervals of 30 seconds, it is determined whether or not the monitoring data is received at a constant time interval (for example, 30 seconds) (S307). Returning to S303, it is determined whether or not there is next transmission data, and transmission is continued. On the other hand, when the monitoring data is not received at a constant time interval, it waits for the monitoring data to be transmitted for a certain time, for example, several minutes (S308). Here, when the monitoring data is received, it is determined that it is normal and the process returns to step S303 to continue the transmission. However, when it is not received, it is determined that an abnormality has occurred and the operator is informed of the occurrence of the abnormality and the socket is closed ( S310). Then, the process returns to step S301 again, passively opens, initializes by requesting reconnection, and starts receiving transmission data again.
[0042]
As described above, in the transmission system having the abnormality monitoring function of the present invention, when monitoring data is not received for a certain period of time, it is determined that an abnormality has occurred and the line is closed once to request reconnection.
[0043]
As a result, it is possible to prevent the connection from being established despite the occurrence of the abnormality, so that the abnormality can be detected promptly.
[0044]
Furthermore, since the terminal device of the present invention transmits monitoring data for each socket and monitors the abnormality for each socket, even when an abnormality occurs in only one of the sockets, the abnormality can be detected. It is also possible to stop only the socket where the error occurred.
[0045]
Therefore, it is possible to prevent a situation in which one socket is stopped due to an abnormality in one socket.
[0046]
In addition, the communication between the pump station and the treatment plant at a remote place in the water supply business will not notice any abnormalities until the operator actually tries to operate the equipment, so the pump will be stopped urgently. Such urgent operations can no longer be made inoperable, causing no serious problems such as water outages, stoppage of water supply, flooding of rainwater, flooding of treatment plants.
[0047]
Note that a program for realizing each process of the terminal device having the above-described abnormality monitoring function can be stored in a recording medium, and the program is executed by reading the recording medium by a computer system. Each process of the terminal device described above can be realized while controlling the above. Here, the recording medium includes a device capable of recording a program, such as a memory device, a magnetic disk device, and an optical disk device.
[0048]
【The invention's effect】
As described above, the transmission system having the abnormality monitoring function of the present invention, the terminal device having the abnormality monitoring function, and the recording medium in which the processing program in the terminal device having the abnormality monitoring function is recorded have a constant cycle. When the monitoring data is sent and received and this monitoring data cannot be sent and received for a certain period of time, it is determined that an error has occurred and the corresponding socket is closed and reconnection is established. It is possible to prevent the connection from being established.
[0049]
As a result, it is possible to quickly detect an abnormality in the line, and it is possible to prevent the terminal apparatus from falling into a non-response state where it does not operate.
[0050]
In addition, monitoring data is sent and received for each socket to monitor each socket, so there is no need to provide a dedicated socket for monitoring line faults, and only faults that cause all lines to malfunction. In addition, even when a failure occurs in which only one socket becomes abnormal, the abnormality can be detected. In addition, since the abnormality is monitored for each socket, even when an abnormality occurs in one socket, it is not necessary to stop other normally transmitting sockets.
[0051]
In addition, when the transmission system of the present invention is used for communication between a pump station and a treatment plant at a remote place in a water supply business, an abnormality is not noticed until the operator actually tries to operate the device. This eliminates the possibility of urgent operations such as an emergency stop of the pump, making it impossible to cause serious situations such as water outages, stoppage of water supply, flooding of rainwater, flooding of treatment plants, etc. It was.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an embodiment of a transmission system having an abnormality monitoring function according to the present invention.
FIG. 2 is a flowchart for explaining processing of a transmission side terminal device of a transmission system having an abnormality monitoring function of the present invention.
FIG. 3 is a flowchart for explaining processing of a receiving side terminal device of a transmission system having an abnormality monitoring function of the present invention.
FIG. 4 is a block diagram for explaining transmission between a treatment plant and a pump station in a water supply business using a conventional transmission system.
FIG. 5 is a flowchart for explaining processing of a transmission-side terminal device of a conventional transmission system.
FIG. 6 is a flowchart for explaining processing of a receiving side terminal device of a conventional transmission system.
[Explanation of symbols]
1, 101 Transmission system
2, 3 Terminal device
4, 7 Transceiver cable
5, 8 Transceiver
6 Ethernet coaxial cable
102 treatment plant
103 Monitoring device
104, 107 PLC
105 Pump station
106 pump
108 Transmission path

Claims (3)

A transmission system having an abnormality monitoring function for monitoring an abnormality when a terminal device equipped with the TCP / IP protocol is connected by a LAN and transmission data is transmitted and received between the terminal devices by socket communication. ,
Sending the transmission data and monitoring data sent at regular intervals to monitor the abnormality for each socket, and when the monitoring data cannot be sent for a certain period of time, close only the socket that could not be sent A first terminal device to be initialized from
A transmission path for transmitting the transmission data and the monitoring data transmitted by the first terminal device;
The transmission data and the monitoring data transmitted through the transmission path are received for each socket, and when the monitoring data is not received for a certain period of time, only the socket that has not been received is closed and then initialized. A transmission system having an abnormality monitoring function characterized by comprising: A terminal device having an abnormality monitoring function for monitoring an abnormality when TCP / IP protocol is implemented and transmission data is transmitted and received by socket communication with other terminal devices connected by a LAN,
When transmitting the transmission data to the other terminal device, the transmission data is transmitted, and monitoring data for monitoring an abnormality is transmitted for each socket at a certain period, and the monitoring data cannot be transmitted for a certain period of time. When closing, only the socket that could not be sent is closed and initialized,
When the transmission data is received from the other terminal device, the transmission data is received, the monitoring data transmitted from the other terminal device at a certain period is received for each socket, and the monitoring data is received for a certain period of time. If not, a terminal device having an abnormality monitoring function characterized in that only a socket that has not been received is closed and then initialized. The TCP / IP protocol is implemented, and a processing program in a terminal device having an abnormality monitoring function for monitoring an abnormality when transmitting / receiving transmission data with other terminal devices connected by a LAN by socket communication is recorded. A recording medium,
When transmitting the transmission data to the other terminal device, a process of transmitting the transmission data, a process of transmitting monitoring data for monitoring an abnormality for each socket at a certain period, and the monitoring data for a certain period of time Including the process of closing and initializing only the socket that could not be sent when it could not be sent,
When receiving the transmission data from the other terminal apparatus, a process of receiving the transmission data, a process of receiving monitoring data transmitted from the other terminal apparatus at a certain period for each socket, and the monitoring data A recording medium recording a processing program in a terminal device having an abnormality monitoring function, comprising: a process of closing only a socket that has not been received for a certain period of time and then initializing the socket.

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