JP3067414B2 - Communication line monitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication line monitoring device applied to a communication system in which communication is performed between a plurality of communication stations connected to a communication line, and more particularly, to a communication line monitoring device applied via a communication line. The present invention relates to a communication line monitor device capable of analyzing the content of a frame on a display screen without dropping even when frames transmitted continuously are transmitted.

[0002]

2. Description of the Related Art In a distributed control system in which high reliability is required, a process control is performed by a plurality of control stations arranged in a distributed manner, and the operation and monitoring of the control stations are performed by communication lines connecting the control stations to each other. The operation is performed by a central operation monitoring device (operator station) that is connected to the communication terminal.

[0003] In such a distributed control system,
If the frame transmitted via the communication line has a defect, correct data and various commands are not sent, which hinders the control operation and monitoring of the process. Therefore, it is convenient to maintain high reliability (maintenance) if the operation monitoring device is provided with a line monitor function for monitoring and analyzing the state of the frame sent via the communication line.

A conventional communication line monitor of this type is:
It is a dedicated device that receives a frame sent via a communication line and analyzes the frame configuration, etc., or a configuration that displays the contents of the received frame as it is on the display screen of the control and monitoring device. there were.

[0005]

However, according to the conventional apparatus configured as described above, when a dedicated analyzer is required or when the transmission of frames is performed continuously, the frame cannot be analyzed. There was a problem that correct analysis of various frames could not be performed, such as the appearance of a frame.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been made in consideration of the above circumstances, and has been made in consideration of the above circumstances. It is an object to provide a monitor device.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a communication line monitoring apparatus for receiving a frame transmitted through a communication line and analyzing the received frame. Receiving means provided with a buffer for receiving the received frame and temporarily holding the received frame; frame analyzing means for analyzing the received frame; display means for displaying an analysis result by the frame analyzing means; Displayed flag means for indicating whether or not the analysis result has been displayed, memory means for storing frames received by the frame receiving means, and, when there are frames received by the frame receiving means, turning off the displayed flag. And the received frames are sequentially stored in the memory means. When the completed flag is off, the latest frame is read from the buffer of the frame receiving means, the frame is analyzed by the frame analyzing means, the analysis result is displayed on the display means, and the display completed flag is turned on. Based on the monitor start means and the command,
Reading the received frame stored in the memory,
The communication line monitor device includes a line monitor display unit that analyzes the frame by the frame analysis unit and displays the analysis result on the display unit.

[0008]

The line monitor starting means stores all the frames received by the frame receiving means via the communication line sequentially in a predetermined area of the memory means, and when there is no frame reception on the communication line, that is, the communication load. When the value of becomes low, the frame is analyzed and the analysis result is displayed.

The line monitor display means is activated by a command, reads out a frame stored in the memory means, analyzes it, and displays it on the display means. This makes it possible to analyze and display a received frame without dropping out even when frame reception continues.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a conceptual diagram showing the configuration of an embodiment of the present invention. This embodiment is a case where the present invention is applied to a distributed control system, and it is assumed that the function of the communication line monitor is configured in the operator station OPS.

In the figure, BS1 and BS2 are communication lines of a duplex configuration, and an operator station OPS in charge of control operation and monitoring and a plurality of distributed control stations FC (here, control stations) in charge of control operation and the like. (Only one is shown). This communication line is usually of a duplex configuration to enhance reliability, but may be of a single configuration.

At the operator station OPS,
Reference numeral 1 denotes communication control means coupled to the communication lines BS1 and BS2, for controlling communication between control stations and between operator stations (hereinafter collectively referred to as communication stations) using the communication lines BS1 and BS2. For example, a well-known token communication control method (a communication control method having a communication right called a token)
Controls communication between a plurality of communication stations.

The communication control means 1 receives a frame having an address corresponding to the address assigned to its own communication station during normal operation. In the case of functioning as, a frame addressed to any communication station transmitted via the communication lines BS1 and BS2 or a frame addressed to a designated communication station can be received.

Reference numeral 2 denotes a frame receiving means for receiving a frame given via the communication control means 1 and having a buffer 21 for temporarily storing the received frame therein. The frame received by the frame receiving means 2 includes a normal token frame indicating a communication right for enabling each communication station connected to the communication line to regularly and fairly transmit data, and a frame connected to the communication line. Control frames such as a diagnostic token frame transmitted to an inactive but inactive communication station, a response frame responding to data reception, a time management frame for time management, and data used for data transmission Various frames such as frames exist.

Reference numeral 3 denotes a frame analyzing means for analyzing a received frame, which analyzes received frame data and finds a source address or a destination address from the frame data.
The contents of the control field are analyzed. 4 is a display means such as a CRT for displaying the analysis result by the frame analysis means 3, 5 is a memory means for storing the frame data received by the frame reception means 2, and 6 is a keyboard which instructs start and stop of the line monitor function. , The address of the communication station to be monitored is specified.

7 is a display means for displaying the analysis result of the received frame.
Is a displayed flag means for indicating whether or not the display has been performed. 8
Is a line monitor start means, which is started when a communication line is monitored. This line monitor start means is realized by software. When a frame is received in the frame receiving means 2, the display completion flag 7 is turned off and the received frame is sequentially stored in the memory means 5, If there is no received frame and the displayed flag 7 is off, the latest frame is read from the buffer 21 of the frame receiving means 2, the frame is analyzed by the frame analyzing means 3, and the analysis result is displayed on the display means 4. , And then the displayed flag 7 is turned on.

Reference numeral 9 denotes line monitor display means, which is started based on, for example, a command from the keyboard 6, reads a received frame stored in the memory means 5, and analyzes the frame by the frame analysis means 3. The analysis result is displayed on the display unit 4. 1
Reference numeral 0 denotes a line monitor stop unit which is activated when the line monitor function is stopped. By activating the line monitor stopping means, the operator station OPS returns to the original control operation and monitoring function.

FIG. 2 is a conceptual diagram showing an example of a frame transmitted through the communication lines BS1 and BS2.
Here, the configuration of the control frame is shown, and the destination station address DA, source station address SA, length field (byte length) LG, control field CTL, header checksum HCS, information checksum ICS INF (information length (variable length depending on the content of the control field)).

FIG. 3 is a conceptual diagram of a storage format when a frame received by the frame receiving means 2 is stored in a predetermined area (line monitor file) of the memory means 6. Here, it is assumed that an area for storing a frame is set in a partial area in the memory, and a line monitor identifier, a start pointer, an end pointer, a line monitor file size, and subsequently, Line monitor data 1 to line monitor data n + 2 can be stored. Here, the start pointer indicates the head of the line monitor data 1, and
The end pointer indicates the end of the line monitor data n + 2. The larger the value of the line monitor data, the more recent the data.

The line monitor data follows the data such as the length of the monitor data, the data type (for example, a type indicating whether it is a data frame or a normal token frame, etc.), the reception time (second, millisecond), and the like. 2 is composed of data in a frame format as shown in FIG. The operation of the device having the above-described configuration will be described below.

FIG. 4 is a flowchart showing the operation of the line monitor start means 8. Operator station O
In the PS, when the line monitor start means 8 is activated, the corresponding operator station becomes a dedicated device for monitoring the communication line, and does not perform a normal control and monitoring function. When the apparatus is dedicated to a communication line monitor, the frame receiving means 2 transmits all frames having a station address to be monitored on the communication lines BS1 and BS2 via the communication control means 1 (for example, to all communication stations or to a designated station). All the frames addressed to the communication station that has been sent).

The line monitor start means 8 first determines whether or not there is a received frame in the frame receiving means 2 (step 1). If there is a received frame, i.e. the frame is continuously received via the communication line,
When it is determined that the communication load is heavy, the display completion flag 7 is turned off (step 2) and the received frames are sequentially stored in the memory means 5 (steps 3 and 4).

In step 1, the frame receiving means 2
If there is no received frame, that is, if it is determined that the communication load is light, it is determined whether or not the displayed flag 7 is on (step 5). The already-displayed flag 7 is provided to prevent the same frame from being analyzed and displayed repeatedly, and is set to OFF when the latest frame has not been displayed yet, and ON when the latest frame has been analyzed and displayed. It is made to become.

In step 5, when the displayed flag 7 is off, the latest frame is read from the buffer 21 of the frame receiving means 2, the frame is analyzed by the frame analyzing means 3, and the analysis result is displayed on the display means 4. Then, the displayed flag 7 is turned on (Steps 6 to 6).
8). Thereafter, such an operation is repeated, and the memory means stores n + 2 received frame data (n is an arbitrary integer, and n can be increased by increasing the file capacity).

The analysis of the received frame stored in the memory means 5 is performed based on a command from the keyboard 6, for example.
This is performed by activating the line monitor display means 9. That is,
When the line monitor display means 9 is activated, the memory means 5
Is read out and sent to the frame analysis means 3 to analyze the frame. Then, the analysis result is displayed on the display unit 4.

FIG. 5 is a view showing an example of the analysis result of the received frame displayed on the display means 4. The display of such an analysis result includes the display by the line monitor starting means 8 and
This is common to the display by the line monitor display means 9. Here, the analysis results of the two received frames are represented by a1,
The received frame data is shown in the columns a2 and b2 while the received frame data is read from the memory as shown in the column b1.

In the columns a1 and b1 showing the analysis results,
(A) shows the reception time of the received frame, (B) shows the status (sts) of the received frame, and "0000" shows that it is a normal frame. (C) is the destination address, (d) is the source address, (e) is the type of control field, and "ACKED-SAP" means SAP data with an immediate ACK response. The receiving station needs to return a response immediately. “Normal-token” means a normal token, and is a frame transmitted to an active communication station connected to a communication line. (F) indicates the length of the frame, (g) indicates the state of the bus in the duplex configuration, and (h) indicates the identification of the receiver that has received the received frame.

By displaying such analysis results, the contents of various frames transmitted to the communication line can be easily understood, and accurate and efficient maintenance work and engineering work can be performed. is there. The function of the communication line monitor is stopped by activating the line monitor stopping means 10.

In the above embodiment, it is assumed that the communication line has a duplex configuration. However, the communication line may have a single configuration. Further, the frames to be monitored are all frames transmitted on the communication line. However, for example, it is also possible to adopt a configuration in which a specific frame can be selected and monitored by designating only a specific frame from the keyboard 6.

[0030]

As described above in detail, according to the present invention, even when the number of frames transmitted on the communication line increases and the communication load increases, the received frames are reliably captured, analyzed, and displayed. Thus, it is possible to provide a communication line monitor device capable of efficiently and accurately performing various trouble analysis and maintenance associated with frame transmission.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing an embodiment of the present invention.

FIG. 2 is a conceptual diagram illustrating an example of a frame transmitted via a communication line.

FIG. 3 is a conceptual diagram of a format of a line monitor file provided in a memory means.

FIG. 4 is a flowchart showing an operation of a line monitor start unit.

FIG. 5 is a diagram illustrating an example of an analysis result of a received frame displayed on a display unit.

[Explanation of symbols]

 BS1, BS2 Communication line FC control station OPS operator station 1 Communication control means 2 Frame reception means 21 Buffer 3 Frame analysis means 4 Display means 5 Memory means 6 Keyboard 7 Displayed flag means 8 Line monitor start means 9 Line monitor display means 10 Line Monitor stop means

Claims (1)

(57) [Claims] 1. A communication line monitor device for receiving a frame sent via a communication line and analyzing the received frame, wherein the buffer receives the frame sent via the communication line and temporarily holds the received frame. A frame receiving means comprising: a frame analyzing means for analyzing the received frame; a display means for displaying an analysis result by the frame analyzing means; and a displayed flag means for indicating whether or not the analysis result of the received frame is displayed. Memory means for storing frames received by the frame receiving means; and if there is a frame being received by the frame receiving means, the display completion flag is turned off, and the received frames are sequentially stored in the memory means. If there is no received frame and the displayed flag is off,
A line monitor start unit that reads the latest frame from the buffer of the frame receiving unit, analyzes the frame by a frame analysis unit, displays the analysis result on a display unit, and turns on the display completion flag; A line monitor display unit for reading a received frame stored in the memory, analyzing the frame by a frame analysis unit, and displaying the analysis result on a display unit.