JP2541502B2 - Control message transmission / reception method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control message transmitting / receiving method for communicating a control message between devices in a system in which a control device and a controlled device are connected via a communication network.

[0002]

2. Description of the Related Art A system to which this type of control message transmitting / receiving method is applied comprises a control device 1, a controlled device 2 and a communication network 3 as shown in FIG.
And the controlled device 2 can communicate with each other.

In this system, as shown in the sequence diagram of FIG. 5, when the control device 1 transmits a control message 11 to the controlled device 2, the controlled device 2 receives the control message 11.
The processing indicated by the control message 11 is executed. Then, the processing result is returned to the control device 1 as a response message 13,
One control ends when the control device 1 receives the returned response message 13.

The processing of the control device 1 at this time is specifically executed according to the flowchart shown in FIG. That is,
The control device 1 first transmits a control message 11 to the controlled device 2 in step 61. Next, at step 62, a time corresponding to the reception waiting time of the response message 13 is set in the response timer provided in advance, and subsequently at step 62, this response timer is started. If the response message 13 can be received before the response timer times out and “YES” is determined in step 63, it is determined that the transmission / reception process has been normally performed, and the process such as analysis of the received response message 13 is performed in step 64. Run with. In addition, the response timer times out before receiving the response message 13
When it is determined to be “NO” in 3, it is determined that an abnormality has occurred in the controlled device 2 or the communication network 3, and the abnormality processing is executed in step 65.

Further, Japanese Patent Laid-Open No. 4-257954 discloses that
There is described a technique in which an operation monitoring unit that monitors the operation of the controlled device is provided in the control device, and the operation monitoring unit obtains and sets a timer value based on the result of monitoring the operating state of the controlled device.

[0006]

In the conventional control message transmitting / receiving method, as shown in FIGS. 4 and 5, the time set in the response timer until the response message 13 is received is controlled by the controlled device 2.
It takes a long time for the control contents to be set to a time corresponding to the control contents. Therefore, if an abnormality occurs in the controlled device 2 or the communication network 3 at this time,
The control device 1 cannot recognize the abnormality until the time set in the timer elapses, and there is a problem that the control device 1 must wait unnecessarily during this period.

There is also a method of setting the value of the response timer for each control content to a time corresponding to the control content, but in this method, it is necessary to remember the value of the response timer for each type of control content, Uses a lot of storage space in the controller. Further, in the case of processing that takes time to control, the value of the response timer also becomes long, and there is the same problem as described above.

Further, in the technique disclosed in Japanese Patent Laid-Open No. 4-257954, in addition to the above-mentioned problem, when the control device stops monitoring the controlled device, an abnormality occurs in the controlled device or the communication network. When this occurs, the control device cannot restart the controlled device monitoring and cannot restart the timer, which causes a problem that the control device cannot get out of the response waiting state of the controlled device.

An object of the present invention is to provide a control message transmitting / receiving method capable of promptly recognizing these abnormalities without wasteful waiting time even if abnormalities occur in a receiving side device or a communication network when transmitting control messages. To do.

[0010]

In order to solve such a problem, the present invention, when the controlled device receives a control message from the control device, checks whether or not the control requires processing time,
If the control takes a long processing time, the step of immediately returning a timer reset message containing the time required for the process to the control device, and the control device based on the time required for the process included in the timer reset message A method comprising the step of resetting a response timer representing a waiting time.

[0011]

When the control device transmits the control message indicating the content of the process instruction to the controlled device, the timer reset message is returned if the process instructed by the controlled device requires a processing time. Since the control device is configured to reset the response timer based on the time required for processing in this timer reset message, for example, even if an abnormality occurs in the communication network or controlled device, a useless waiting time These abnormalities can be recognized promptly without the need for.

[0012]

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

FIG. 1 is a sequence diagram showing an embodiment of a control message transmitting / receiving method according to the present invention. A system to which this control message transmitting / receiving method is applied is composed of a control device 1, a controlled device 2 and a communication network 3 as shown in FIG. Here, as shown in the sequence diagram of FIG. 1, the control device 1 first transmits a control telegram 11 indicating the processing content of the controlled device 2 to the controlled device 2. Then, the controlled device 2 receives the control telegram 11, immediately determines the processing content instructed by the control telegram 11, calculates the time required for the processing, and if the processing takes time, the timer is used. The reset message 12 is returned to the control device 1. After that, the controlled device 2 executes the process instructed by the control message 11, and when the process is completed, transmits the response message 13 to the control device 1.

FIG. 2 is a flow chart showing the operation of the control device 1. The operation of the control device 1 will be described in detail according to this flowchart.

The control device 1 first transmits a control message 11 to the controlled device 2 in step 21. Then, in step 22, the default value of the reception waiting time of the response message 13 is set in the response timer, and the counting of this response timer is started.

If any message is received from the controlled device 2 before the response timer times out ("YES" in step 23), the type of the received message is checked,
If it is the timer reset message 12 (“timer reset message” in step 25), the message is previously sent to the controlled device 2 at the time required for the processing in the controlled device 2 included in the timer reset message 12. The response timer is reset to a time including the time from the transmission to the reception of the timer reset message, and the counting of the response timer is started (step 24).

If the electronic message received from the controlled device 2 is the response electronic message 13 ("response electronic message" in step 25),
Assuming that the transmission / reception of the control message 11 has been normally performed, the normal processing is executed in step 26.

If no message is received from the controlled device 2 before the response timer times out (“NO” in step 23), it is determined that an abnormality has occurred in the controlled device 2 or the communication network 3. Then, the process proceeds to 27 and the process as abnormal is performed.

FIG. 3 is a flow chart showing the operation of the controlled device 2 in response to the operation of the control device 1 as described above. The operation of the controlled device 2 will be described according to this flowchart.

The controlled device 2 first receives the control message 11 from the control device 1 in step 31. Then, it is determined whether the control instructed by the control message 11 takes time to execute, and if it takes time (step 32).
Then, "YES"), the timer reset message 12 including the time required to execute the process is transmitted to the control device 1 (step 33), and then the instructed process is performed (step 34).

If the process is not time-consuming ("NO" in step 32), the timer reset message in step 33 is not transmitted.

After that, if the processing is completed within the time ("YES" in step 35), the processing result is transmitted to the control device 1 as a response telegram 13 in step 36.

If the processing is not completed within the time ("NO" in step 35), the timer reset message is transmitted again (step 33) and the processing is continued.

[0024]

As described above, according to the present invention, when a control telegram indicating a processing instruction content is transmitted from the control device to the controlled device, if the controlled device takes time, Since the timer reset message is returned and the response timer is reset based on the time calculated based on the processing time included in the message, the default value of the response timer can be shortened, and the communication network 3 And controlled device 2
Even if an abnormality occurs in the control device 1, the control device 1 can promptly recognize the abnormality without needing a useless waiting time and without remaining in a standby state.

Further, if the processing does not take time, the timer reset message is not transmitted, and unnecessary message transmission / reception is not performed.

Further, even if the controlled device 2 is added or changed and the time taken to execute the process changes,
The response timer value can be set according to the processing time without newly changing the setting of the control device 1.

[Brief description of drawings]

FIG. 1 is a sequence diagram showing an operation of each device in a system to which a control message transmitting / receiving method according to the present invention is applied.

FIG. 2 is a flowchart showing an operation of a control device in the system.

FIG. 3 is a flowchart showing an operation of a controlled device in the system.

FIG. 4 is a block diagram of a system to which a control message transmitting / receiving method is applied.

FIG. 5 is a sequence diagram illustrating a conventional control message transmitting / receiving method.

FIG. 6 is a flowchart illustrating a conventional control message transmitting / receiving method.

[Explanation of symbols]

 1 Control Device 2 Controlled Device 3 Communication Network 11 Control Message 12 Timer Reset Message 13 Response Message

Claims (3)

(57) [Claims] 1. A control device and a controlled device, wherein the controlled device executes the instructed process when receiving a control message indicating the instruction content of the process from the control device. In the system that sends a response message indicating the result, the control device sends a control message to the controlled device.
Set the default value of the response message reception waiting time to the response timer and start counting, and the controlled device calculates the time required for the process instructed by the control message, and if it is a time-consuming process, The timer reset message including the time required for the processing is returned to the control device, and the control device resets the response timer at the time calculated based on the time included in the timer reset message. Control message sending / receiving method. 2. The time calculated based on the time included in the timer reset message is transmitted to the controlled device at a time required for processing by the controlled device included in the timer reset message. The method for transmitting and receiving a control message according to claim 1, wherein the time is a time obtained by adding a time from when the message for resetting the timer is received until the message for resetting the timer is added. 3. The control message transmitting / receiving method according to claim 2, wherein the controlled device retransmits the timer reset message if the process is not completed within the time required for the process.