JP2001292151A - Master-slave transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a master-slave transmission system, speedily detecting the same request message as a request message, is received during transmitting an answer message to the request message on the side of a slave device, so as to report it as alarm information. SOLUTION: When the reception of the request message is completed, a transmission control part 312 records the header of the request message in an reception abnormality header pattern area in a transmission operation area 311 as a reception abnormality header pattern, and a transmission interface part 313 divides the answering message and transmits them to a master device. When the request message is received during transmitting the answer message, the part 313 compares the header of the request message with the reception abnormality header pattern, recorded in the reception abnormality header pattern area in the area 311. A system control part 303 reports alarm information, when information on reception abnormality is recorded in a log area in the area 311.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a master device and a slave device connected to each other via a transmission line, and the master device divides a request message for each transmission cycle and transmits the request message to the slave device. And a master-slave transmission system in which a slave device divides a response message to the request message and transmits the message to the master device.

[0002]

2. Description of the Related Art FIG. 8 is a diagram showing a configuration example of a conventional master / slave transmission system.

As shown in FIG. 8, in the conventional example, a central station 100 having a power supply unit 20, a programmable controller 30 and a master unit 40, and a slave unit 7
0-1 to 70-n are connected to each other via a transmission line 50, and the master device 40 and the slave devices 70-1 to 70-7 are connected to each other.
Messages are exchanged with each other between 0-n.

The maintenance monitoring device 10 is connected to a programmable controller 30 provided in the central office 100,
The transmission cycle of the master device 40 is set.

[0005] The following describes a master device configured as described above.
The operation at the time of message exchange in the slave transmission system will be described. Here, message exchange performed between master device 40 and slave device 70-1 will be described.

[0006] In the master device 40, the request message is divided, the same header is added to each of the divided request messages, and the request message is transmitted every transmission cycle set by the maintenance monitoring device 10. It is transmitted to the slave device 70-1.

[0007] In the slave device 70-1, when the request message transmitted from the master device 40 is received,
A response message to the request message is created, and the response message is divided and transmitted to the master device 40.

Hereinafter, the master device 40 and the slave device 7
The message exchange performed between 0 and 1 will be described in detail using a time chart.

FIG. 9 is a time chart showing an example of transmission timing at the time of message exchange performed between the master device 40 and the slave device 70-1 shown in FIG. The time chart for a sufficiently long time is shown. In FIG. 9, request messages 1-1 to 1-3 and 2-1 to 2-3, transmitted from the master device, are shown.
3-1 to 3-3 are originally divided from the same request message.

As shown in FIG. 9, when the transmission cycle of the master device 40 is set sufficiently long in accordance with the response of the slave device 70-1, the slave device 70-1 sets the transmission cycle within the transmission cycle. It is possible to transmit a response message to the master device 40, and thereafter, the message is exchanged between the master device 40 and the slave device 70-1 in each transmission cycle.

FIG. 10 is a time chart showing an example of transmission timing at the time of message exchange performed between the master device 40 and the slave device 70-1 shown in FIG. The time chart for a short case is shown. In FIG. 10, request messages 1-1 to 1-3, 2-1 to 2-3, 3 transmitted from the master device are shown.
-1 to 3-3 are originally divided from the same request message.

As shown in FIG. 10, when the transmission cycle of the master device 40 is set to be short in order to improve the data exchange efficiency, the slave device 70-1 transmits the data to the master device 40 within the transmission cycle. The response message cannot be transmitted to the request message 1-1 to 1-3, and during the transmission of the response message 1'-1 to 1'-3 for the request message 1-1 to 1-3, the request message 1-1 to 1-1 is transmitted.
-3, the request message 2-1 which is originally the same request message may be received. In this case, the slave device 70-1
In, after the transmission of the response messages 1'-1 to 1'-3 being transmitted is completed, the response message 2'-1 for the request message 2-1 is transmitted to the master device 40.

[0013]

As described above, in the conventional master-slave transmission system, if the transmission cycle of the master device is short, the slave device will
During the transmission of a response message to a request message, there may be a case where the same request message as the original request message is received. In this case, after the transmission of the response message being transmitted is completed, the response message A response message to the request message received during transmission will be transmitted to the master device, but if such a condition continues, eventually the uniqueness between the request message and the response message will be lost. In addition to this, the message always exists on the transmission path, and the transmission efficiency of the transmission path may be reduced. Therefore, during the transmission of the response message to the request message, if the detection of a reception error that the same request message was originally received is delayed, this may affect the entire system. There is.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. In a slave device, during transmission of a response message to a request message, the request message is It is an object of the present invention to provide a master-slave transmission system that can quickly detect the reception of the same request message and report it as alarm information when the same request message is received.

[0015]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a central station having a master device, a slave device connected to the master device via a transmission line, and a transmission device for the master device. The master device, after dividing the request message, adding the same header to each of the request messages and transmitting the request message with the maintenance monitoring device. The slave device transmits the message to the slave device at every set transmission cycle, the slave device creates a response message to the request message transmitted from the master device, divides the response message, and divides the response message into the master message. In a master / slave transmission system for transmitting to a device, the slave device transmits a message for recording a header of the request message transmitted from the master device as a reception abnormal header pattern. When the transmission of the response message is completed, the reception error header pattern recorded in the transmission work area is cleared, and during transmission of the response message, the transmission message is recorded in the transmission work area. When a request message to which the same header as the received abnormal header pattern is added is received, alarm information is reported.

Further, the slave device creates a transmission interface for receiving a request message transmitted from the master device, and creates a response message for the request message received by the transmission interface. A transmission control unit that records a header of the request message as the reception abnormal header pattern in the transmission work area; and a system control unit that manages the entire slave device. Divide the response message created by the section and send it to the master device,
When the transmission of the response message is completed, the reception abnormal header pattern recorded in the transmission work area is cleared, and the transmission abnormality header recorded in the transmission work area is transmitted during the transmission of the response message. When a request message to which the same header as the pattern is added is received, information to that effect is recorded in the transmission work area as a reception error, and the system control unit stores the information of the reception error in the transmission work area. When recorded, the alarm information is reported.

Further, the transmission work area includes a reception error header pattern area in which the reception error header pattern is recorded, and a log area in which the reception error information is recorded.

Further, when the alarm information is reported by the slave device, the maintenance and monitoring device sets the transmission cycle again based on the alarm information.

(Operation) In the present invention configured as described above, in the slave device, the header of the request message transmitted from the master device is recorded as a reception abnormal header pattern in the transmission work area, and the response message While sending,
When a request message to which the same header as the reception abnormal header pattern recorded in the transmission work area is added is received, alarm information is reported.

Therefore, during transmission of a response message to the request message, the slave device can easily determine whether or not the same request message as the request message was originally received by using the reception abnormal header pattern. And quickly detected.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of a master / slave transmission system according to the present invention. In the figure,
The same parts as those of the master / slave transmission system shown in FIG. 8 are denoted by the same reference numerals, and detailed description will be omitted.

In the present embodiment, as shown in FIG.
Instead of the slave devices 70-1 to 70-n shown in
The header of the request message transmitted from the master device 40 is recorded in a transmission work area (not shown) as a reception abnormal header pattern. Slave devices 60-1 to 60-n for reporting alarm information when a request message to which the same header is added are provided, and the other components are the master-slave transmission system shown in FIG. Is the same as

As a method of reporting the alarm information, a method of displaying the alarm information on the LEDs (not shown) of the slave devices 60-1 to 60-n or a method of transmitting the alarm information to the master device 40 as status data is provided. There is a method to do.

The following is a description of the master configured as described above.
The operation at the time of message exchange in the slave transmission system will be described. Here, message exchange performed between master device 40 and slave device 60-1 will be described.

In the master device 40, the request message is divided, and the same header is added to each of the divided request messages. This request message is transmitted at every transmission cycle set by the maintenance monitoring device 10. Sent to slave device 60-1.

In the slave device 60-1, a response message to the request message transmitted from the master device 40 is created, and the created response message is divided and transmitted to the master device 40. The header of the request message transmitted from the master device 40 is recorded as a reception abnormal header pattern in a transmission work area described later.

The abnormal reception header pattern recorded in the transmission work area is cleared when the transmission of the response message is completed.

Here, when the transmission cycle of the master device 40 is set short, the slave device 60-1
In some cases, the request message is received during transmission of the response message, that is, before the reception abnormal header pattern recorded in the transmission work area is cleared. In this case, the slave device 60-1 receives the response message. The header of the request message received during transmission of the message is compared with the reception abnormal header pattern recorded in the transmission work area.

In the slave device 60-1, for example, if a request message originally identical to the request message is received during transmission of a response message to the request message, the transmission of the response message is performed. The header of the request message received during the transmission matches the reception abnormal header pattern recorded in the transmission work area. For this reason, if both match, it is detected that a request message originally identical to this request message was received during transmission of a response message to the request message, and information to that effect is received abnormally. Is recorded in the transmission work area described above.

In the slave device 60-1, when a reception error is recorded in the transmission work area, alarm information is reported by an LED display or the like.

As described above, in the present embodiment, the slave devices 60-1 to 60-n have the master device 40
The header of the request message transmitted from is recorded in the transmission work area as a reception abnormal header pattern, and the same header as the reception abnormal header pattern recorded in the transmission work area is added during transmission of the response message. Is configured to report alarm information when a request message that has been received is received. During transmission of a response message to the request message, the same request message originally received as this request message is received. Whether it has been done can be easily and quickly detected using the reception abnormal header pattern.

Therefore, for example, in the case where the maintenance monitoring device 10 is configured to reset the transmission cycle of the master device 40 based on the alarm information reported by the slave devices 60-1 to 60-n. Thereafter, the message is exchanged between the master device 40 and the slave devices 60-1 to 60-n for each reset transmission cycle, whereby the request message and the response message are exchanged. And the transmission efficiency in the transmission path 50 can be prevented from lowering.

FIG. 2 shows the slave device 60- shown in FIG.
FIG. 1 is a block diagram illustrating a configuration example of 1 to 60-n.

As shown in FIG. 2, this configuration example has a system control means 300 comprising an I / O port circuit 302 connected to an LED (not shown) and a switch 301 and a system control section 303 for managing the entire slave device. And a transmission work area 311 in which a reception error header pattern, reception error information, etc. are recorded, manages messages,
Transmission control unit 312 which records the header of the request message transmitted from 0 as a reception abnormal header pattern in transmission work area 311 and transmission interface unit 313 which exchanges messages with master device 40. Means 310 and the transmission connector 314
Is connected to the transmission line 50 via the.

FIG. 3 shows the transmission work area 311 shown in FIG.
FIG. 3 is a diagram showing an example of a data configuration in the example.

As shown in FIG. 3, in this example, a reception error header pattern area in which a reception error header pattern is recorded and a log area in which information on the reception error is recorded when a reception error is detected. Is provided.

The operation of the slave device configured as described above will be described below with reference to a time chart shown in FIG.

FIG. 4 is a time chart for explaining the operation of the slave device shown in FIG. In addition,
In FIG. 4, request message 1 transmitted from the master device
-1 to 1-3, 2-1 to 2-3, and 3-1 to 3-3 are originally divided from the same request message, and the added headers are the same as each other. And

First, the transmission interface unit 313 receives request messages 1-1 to 1-3 from the master device.

When the transmission interface unit 313 completes the reception of the request messages 1-1 to 1-3, the transmission control unit 31
2, a response message to the request messages 1-1 to 1-3 is created, and the headers of the request messages 1-1 to 1-3 are transmitted as reception abnormal header patterns in the transmission work area 311.
Is recorded in the reception abnormal header pattern area, and then the transmission processing is started.

When the transmission control unit 312 starts the transmission process, the transmission interface unit 313 converts the response message created by the transmission control unit 312 into the response message 1'-1.
~ 1'-3 divided and transmitted to the master device,
When the transmission of the response messages 1'-1 to 1'-3 is completed, the abnormal reception header pattern recorded in the abnormal reception header pattern area of the transmission work area 311 is cleared.

Similarly, when the transmission interface unit 313 completes the reception of the request messages 2-1 to 2-3, the transmission control unit 312 creates response messages for the request messages 2-1 to 2-3. And the request messages 2-1 to 2-
The header of No. 3 is recorded as an abnormal reception header pattern in the abnormal reception header pattern area of the transmission work area 311. Subsequently, the transmission process is started.

When the transmission control unit 312 starts the transmission process, the transmission interface unit 313 converts the response message created by the transmission control unit 312 into the response message 2'-1.
~ 2'-3 and transmitted to the master device.

Here, in the transmission interface unit 313, during transmission of the response message 2'-1 to 2'-3, that is, before the reception abnormal header pattern recorded in the transmission work area 311 is cleared. , The request message 3-1 from the master device 40 may be received. In this case, the request message 3-1 is transmitted to the transmission interface unit 313.
Is compared with the reception abnormal header pattern recorded in the reception abnormal header pattern area of the transmission work area 311.

At this time, the reception abnormal header pattern recorded in the reception abnormal header pattern area of the transmission work area 311 is the header of the request messages 2-1 to 2-3, and the request messages 2-1 to 2-3. -3 and the header of the request message 3-1 are the same, so that the response messages 2'-1 to 2'-
As a result of comparing the header of the request message 3-1 received during the transmission of No. 3 with the abnormal reception header pattern recorded in the abnormal reception header pattern area of the transmission work area 311, they match.

When both match, that is, while the response messages 2'-1 to 2'-3 for the request messages 2-1 to 2-3 are being transmitted, the request messages 2-1 to 2-3 are not transmitted. When it is detected that the request message 3-1 which is originally the same request message has been received, information on the reception error is recorded in the log area of the transmission work area 311.

When the information on the reception error is recorded in the log area of the transmission work area 311, the system control unit 303 performs processing such as displaying the information on the reception error on an LED (not shown). , Alarm information is reported.

FIG. 5 is a flowchart for explaining the operation of the transmission control unit 312 shown in FIG. 2, and is a flowchart executed in the foreground after the completion of reception of the request message from the master device.

In the transmission control unit 312, when the request message from the master device is received by the transmission interface unit 313, the request message is analyzed (step S1).
0), a response message to the request message is created (step S11).

Next, the header of the request message is recorded as an abnormal reception header pattern in the abnormal reception header pattern area of the transmission work area 311 (step S12), and the transmission process is started (step S12).

FIG. 6 is a flowchart for explaining the operation of the transmission interface unit 313 shown in FIG. 2 when transmitting a response message, and shows a flowchart executed for each transmission interrupt.

In the transmission interface unit 313, when the transmission process is started by the transmission control unit 312, the response message created by the transmission control unit 312 is divided and transmitted to the master device (step S12). S20).

Here, it is determined whether the transmission of the response message has been completed (step S21). If it is determined that the transmission of the response message has been completed, the response message is recorded in the reception abnormal header pattern area of the transmission work area 311. The received reception error header pattern is cleared (step S22).

On the other hand, if it is determined in step S21 that the transmission of the response message has not been completed, the process returns to step S20, and the transmission process of the response message to the master device is continuously performed.

FIG. 7 is a flowchart for explaining the operation of the transmission interface unit 313 shown in FIG. 2 at the time of receiving a request message, and shows the operation executed for each reception interrupt.

In the transmission interface unit 313, when a request message transmitted from the master device is received, the header of the request message and the reception error header recorded in the reception error header pattern area of the transmission work area 311 are received. It is determined whether or not the pattern matches (step S30). If it is determined that the two do not match,
A receiving process such as taking in the received request message is performed (step S32).

On the other hand, if it is determined in step S30 that they match, information on abnormal reception is recorded in the log area of the transmission work area 311 (step S3).
1) Thereafter, the process proceeds to the process in step S32, and the receiving process is performed.

[0059]

As described above, in the present invention,
In the slave device, the header of the request message transmitted from the master device is recorded in the transmission work area as a reception abnormal header pattern, and during transmission of the response message, the reception abnormal header pattern recorded in the transmission work area is When a request message to which the same header is added is received, alarm information is reported. Therefore, during transmission of a response message to the request message, the request message is originally the same as this request message. Can be easily and quickly detected using the reception abnormal header pattern.

Further, in the case where the transmission cycle is set in the maintenance monitoring device based on the alarm information reported by the slave device, the communication between the master device and the slave device is performed for each set transmission period. Therefore, the message exchange is performed between the request message and the request message, so that the uniqueness between the request message and the response message can be maintained, and a decrease in the transmission efficiency of the transmission path can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a master-slave transmission system of the present invention.

FIG. 2 is a block diagram illustrating a configuration example of a slave device illustrated in FIG. 1;

FIG. 3 is a diagram illustrating an example of a data configuration in a transmission work area illustrated in FIG. 2;

FIG. 4 is a time chart for explaining an operation of the slave device shown in FIG. 2;

FIG. 5 is a flowchart for explaining an operation in the transmission control unit shown in FIG. 2;

FIG. 6 is a flowchart for explaining an operation at the time of transmitting a response message in the transmission interface unit shown in FIG. 2;

FIG. 7 is a flowchart for explaining an operation at the time of receiving a request message in the transmission interface unit shown in FIG. 2;

FIG. 8 is a diagram showing a configuration example of a conventional master / slave transmission system.

9 is a time chart showing an example of transmission timing at the time of message exchange performed between the master device and the slave device shown in FIG. 8;

FIG. 10 is a time chart illustrating an example of transmission timing at the time of message exchange performed between the master device and the slave device illustrated in FIG. 8;

[Explanation of symbols]

 Reference Signs List 10 maintenance monitoring device 20 power supply device 30 programmable controller 40 master device 50 transmission line 60-1 to 60-n slave device 100 central station

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (4)

[Claims] A central station having a master device, a slave device connected to the master device via a transmission line,
A maintenance monitoring device for setting a transmission cycle of the master device, wherein the master device divides the request message, adds the same header to each of the request messages, and The slave device transmits to the slave device for each transmission cycle set by the maintenance monitoring device, and the slave device creates a response message to the request message transmitted from the master device, and generates the response message. In a master-slave transmission system for dividing and transmitting to the master device, the slave device is a transmission work area for recording a header of the request message transmitted from the master device as a reception abnormal header pattern. Comprising, when the transmission of the response message is completed, while clearing the reception abnormal header pattern recorded in the transmission work area, during transmission of the response message A master / slave transmission system for reporting alarm information when a request message with the same header as the reception abnormal header pattern recorded in the transmission work area is received. 2. The master-slave transmission system according to claim 1, wherein the slave device receives a request message transmitted from the master device, and receives the request message from the master device. A transmission control unit that creates a response message to the request message, and records a header of the request message in the transmission work area as the reception abnormal header pattern, and a system control unit that manages the entire slave device. The transmission interface unit divides the response message created by the transmission control unit and transmits the divided response message to the master device. When the transmission of the response message is completed, the transmission interface unit transmits the response message. While clearing the reception abnormal header pattern recorded in the work area, the reception recorded in the transmission work area during transmission of the response message. When a request message to which the same header as the abnormal header pattern is added is received, information to that effect is recorded in the transmission work area as a reception abnormality, and the system control unit detects the reception abnormality in the transmission work area. A master / slave transmission system for reporting the alarm information when information is recorded. 3. The master / slave transmission system according to claim 2, wherein the transmission work area is a reception error header pattern area in which the reception error header pattern is recorded, and a log in which the information on the reception error is recorded. A master-slave transmission system, comprising: 4. The master / slave transmission system according to claim 1, wherein the maintenance monitoring device is configured to perform a maintenance operation on the basis of the alarm information when the alarm information is reported by the slave device. And setting the transmission cycle again.