JP2006345171A - Data transmitting method and data transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data transmission system which reduces delay of transmission processing from an arbitrary program to a transmission destination device when messages are transmitted from a plurality of programs to the transmission destination device. <P>SOLUTION: In the data transmission system, a main station M is equipped with: a message storage section 11 which stores different message data 21 from the plurality of programs incorporated in communication software performing communication with a slave station S, a message priority level judgement processing section 12 which compares priority levels of all messages stored in the message storage section 11; a transmission processing section 14 which transmits the messages from the message storage section 11 to the transmission destination device in the order of emergency levels of the priority levels; and a timer counting section 13 which counts elapsed times by messages of low priority levels after transmission from the plurality of programs when the messages of low priority levels are stored in the message storage section 11, and outputs a message whose elapsed time reaches a defined value preferentially from messages of high priority levels, to the transmission processing section 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a data transmission method and a data transmission system that performs data transmission between a master station and a slave station via a transmission line, and relates to a destination device that is a slave station that can receive and process only a single message at a time. The present invention also relates to a method for transmitting messages simultaneously from a plurality of programs that are installed in communication software of a main station and operate asynchronously.

Conventionally, a data transmission system that performs data transmission between a master station and a slave station via a transmission line is as shown in FIG. FIG. 2 is a configuration diagram of a data transmission system that performs data transmission between a general master station and slave stations.
In such a data transmission system, for example, 17 bytes / 32 bytes of data is always communicated between about 250 μs to 8 ms between one master device (master station) and up to about 30 slave devices (slave stations). Cyclic bidirectional communication can be performed in a cycle. The above master device is configured with software (communication software) that is installed in a personal computer or computer and executes communication, and the slave device is configured with a servo driver, input / output module, counter module, or the like. The
In such a configuration, since a message is asynchronously transmitted from a plurality of programs inside the communication software of the main station to a destination device that becomes an asynchronous slave, for example, a message is transmitted from a program other than the plurality of programs. If there is, there may be a delay until an arbitrary message is transmitted to the destination device depending on the transmission timing and the reception process of the destination device.
In addition, when you want to receive a response from a specific program message preferentially from the destination device, the corresponding program will synchronize to stop sending messages from other programs at the timing of sending the message. (For example, refer to Patent Document 1).
JP-A-5-316124 (pages 3 to 4 and FIG. 4)

In the above method, in a system in which multiple programs asynchronously send messages to the destination device, when the program sends to the destination device, exclusive processing is performed and the transmission data is sent while another program is being sent. The data is not overwritten, and the transmission process of another program is executed after the transmission process of the transmission data is completed. When the transmission destination device receives the message, it returns a BUSY status even if the program attempts to transmit the message so that the message is not sent until the reception process is completed. The program that receives it waits for a certain period of time and transmits again. In order to explain an example of such a system in an easy-to-understand manner, the following is described.
For example, consider a case where four programs (program A, program B, program C, and program D) perform message transmission processing for processing time T1 asynchronously to a transmission destination device. In such a case, when the program B, the program C, and the program D start the transmission process immediately after the program A starts the transmission process to the transmission destination device at a certain timing, the programs B, C, and D are controlled by the exclusive process. However, immediately after the completion of the transmission process of program A, even if program B starts the transmission process, the reception process at the processing time T2 of the transmission destination device is not completed. On the other hand, BUSY is returned. For this reason, the program B enters a process of waiting for a fixed time and resending the message, but when the program B finishes the exclusive process for waiting, the program C starts the transmission process. Since the receiving process of the destination device is sometimes completed, the destination device can receive the program C message. At this time, the standby time of program B ends and transmission processing starts. However, because the transmission destination device is in reception processing, it returns BUSY to program B again, and program B enters a standby state for retransmission. Then, there is a possibility that the program D starts the transmission process and the message of the program D is processed by the destination device. After the message of the program D is processed, the message of the program B and the program B is transmitted. Even if the sentence is processed, the transmission time T1 + T1 of the programs C and D from the timing when the program B tries to transmit the message, the processing time T2 + T2 of the message transmitted from the programs C and D of the destination device, The overhead α such as the waiting time for retransmitting the sentence is at least taken, causing a significant delay in the processing of the program B Further, if the transmission processing of the programs C and D is performed immediately before the retransmission timing of the program B, a further delay occurs. In order to solve this problem, it is necessary to incorporate a common synchronization system with independent programs, but there is a problem that the program becomes complicated. In order to avoid this, it was necessary to synchronize independent programs in the message transmission process.
The present invention has been made in view of such a problem. When a message is transmitted from a plurality of programs operating asynchronously to a destination device, the transmission processing from each program and the reception processing of the destination device overlap. However, it is an object of the present invention to provide a data transmission method and a data transmission system that can reduce a delay in transmission processing from an arbitrary program to a destination device.

In order to solve the above problem, the present invention is configured as follows.
The invention according to claim 1 is a data transmission method for performing data transmission between a master station and a slave station via a transmission line, and the master station is incorporated in communication software for executing communication with the slave station. Different message data from a plurality of programs is stored in the message storage unit, the priority of all messages stored in the message storage unit is compared in the message priority determination processing unit, and the message According to the priority urgency level from the storage unit, the messages with the highest urgency level are transmitted in order from the slave unit to the destination device via the transmission processing unit. When stored, the elapsed time is counted using a timer count unit that uses the elapsed time after being transmitted from a plurality of programs for each message for the lower priority message as a specified timer value. The message that reaches the specified value is stored in the message storage section. And it is obtained by so as to output to the transmission processing section earlier than Denbun with priority high that is.
According to a second aspect of the present invention, there is provided a data transmission system for performing data transmission between a master station and a slave station via a transmission line, wherein the master station includes communication software for executing communication with the slave station. A message storage unit for storing different message data from a plurality of incorporated programs, and a message priority determination processing unit for comparing the priorities of all messages stored in the message storage unit According to the urgency of priority from the message storage unit, a transmission processing unit for transmitting to the destination device on the slave station in order from the message with the highest urgency, and the priority in the message storage unit When a low message is stored, the elapsed time after being transmitted from the multiple programs for each message for the low priority message is set as a specified timer value, and the elapsed time is counted. The message that reached the specified value It is obtained by a timer count unit for outputting ahead Denbun priority high stored in the storage unit to the transmission processing section.

  According to the first and second aspects of the present invention, when a message is transmitted to a destination device from a plurality of programs operating asynchronously, the transmission processing from each program and the reception processing of the destination device overlap. Even if the priority is given to the transmission message and the transmission process is managed by the message transmission timer, the program that performs the message transmission process can be started from any program without considering the transmission process timing. It is possible to obtain a data transmission method and a data transmission system that can reduce the delay of transmission processing to the network.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a data transmission system showing an embodiment of the present invention.
In FIG. 1, 1 is a message transmission processing unit, 11 is a message storage unit, 12 is a message priority determination processing unit, 13 is a timer count processing unit, 14 is a transmission processing unit, 2 is transmission data, and 21 is transmission. Message 22 is a priority.
The features of the present invention are as follows.
That is, in a data transmission system that performs data transmission between the master station M and the slave station S via a transmission line, the master station M includes a plurality of pieces of software installed in communication software that performs communication with the slave station S. A message storage unit 11 for storing different message data 21 from the program, a message priority determination processing unit 12 for comparing the priorities of all messages stored in the message storage unit 11, The transmission processing unit 14 for transmitting messages from the message storage unit 11 to the transmission destination device on the slave station S in order from the message with the highest urgency according to the urgency level of the priority order. When the message is stored, the elapsed time after being transmitted from multiple programs for each message for the low priority message is set as the specified timer value, and the elapsed time is counted and specified The message storage unit 1 It has become those with a timer count unit 13 for outputting previously to the transmission processing unit 14 from Denbun priority high stored in.

Next, the operation will be described with reference to FIG.
When the transmission data 2 is processed in the message transmission process in the program, the message data is stored in the message storage unit 11 which is the common message transmission processing unit 1.
At this time, if no other message data is stored in the message storage unit 11, a message is immediately transmitted from the transmission processing unit 14 to a destination device (not shown). When the transmission process for the message transmission processing time T1 and the reception processing time T2 of the destination device (not shown) is shorter than the total time of the transmission processing, Accumulated in the message storage unit 11.
When the processing of the first message ends in the transmission processing unit 14, the message priority determination processing unit 12 compares the priorities of all messages stored in the message storage unit 11. At this time, when there is an urgent message with priority, there is no urgent message with priority urgent message transmitted to the destination device (not shown) by the transmission processing unit 14. Is transmitted to the transmission destination device (not shown) by the transmission processing unit 14. When there is no message with priority priority or high priority, a message with low priority is transmitted by the transmission processing unit 14 to a destination device (not shown). With this mechanism, it is possible to prevent a delay in any message processing time by giving a higher priority to a message for which processing is to be prioritized.
The transmission processing unit 14 receives BUSY when reception processing of the transmission destination device (not shown) is not completed at the time of transmission of a message to the transmission destination device (not shown), but to the transmission destination device (not shown). The transmission process is repeated continuously until the message is ready for transmission. The timer count processing unit 13 counts the elapsed time after being transmitted from a plurality of programs for each low priority message when a low priority message is stored. A message whose elapsed time count reaches a specified timer value is transmitted to a transmission destination device (not shown) by the transmission processing unit 14 prior to a message of high priority stored in the message storage unit 11. Is done. With this mechanism, even if only a high priority message is transmitted from the program in a state where a low priority message is stored in the message storage unit 11, the priority is always given after a certain period of time. Since low-order messages are sent to the destination device (not shown), all messages can be sent without significant delays without complicated control of message priority and transmission timing. Can process. When a plurality of messages having the same priority order are stored in the message storage unit 11, the transmission processing unit 14 transmits them to the transmission destination device (not shown) in the order of storage.

  The embodiment of the present invention temporarily stores messages transmitted from a plurality of programs to a transmission destination device and the priority of the corresponding message, and compares the priority of stored messages at the timing of transmission to the transmission destination device. The message with the higher priority stored in the message is sent to the destination device and the elapsed time after transmission from multiple programs even if the priority is lower. Since it is configured to have a function to transmit to the destination device before the sentence, the delay time from the message transmission timing from the program until the message is actually transmitted to the destination device is It can be shortened.

  Since the data transmission system according to the present invention can transmit a message to the transmission destination device with a slight delay from the intended timing, the message transmission waiting time is reduced and the throughput of the entire system is increased. Therefore, such a data transmission system can be applied to contour control between multiple axes in which all the master station and slave stations are synchronized.

Configuration diagram of a data transmission system showing an embodiment of the present invention Configuration diagram of a data transmission system that performs data transmission between a general master station and slave stations

Explanation of symbols

1 message transmission processing section,
11 Message storage unit,
12 message priority determination processing unit,
13 Timer count processing section,
14 Transmission processing unit,
2 transmission data,
21 Send message,
22 Priority

Claims (2)

In a data transmission method for performing data transmission via a transmission line between a master station (M) and a slave station (S),
The message data storage unit (11) stores different message data from a plurality of programs incorporated in communication software for performing communication between the master station (M) and the slave station (S),
The priority order of all messages stored in the message storage unit (11) is compared in the message priority determination processing unit (12),
According to the priority of the priority order from the message storage unit (11), the messages are transmitted in order from the message with the highest urgency to the destination device on the slave side (S) via the transmission processing unit (14),
When a message with a low priority is stored in the message storage unit (11), an elapsed time after transmission from a plurality of programs for each message is specified for the message with a low priority. Using a timer count unit (13) as a timer value, a message that has reached the specified value by counting the elapsed time is preceded by a message with a higher priority stored in the message storage unit (11). And outputting to the transmission processing unit (14). In a data transmission system that performs data transmission via a transmission line between a master station (M) and a slave station (S),
The master station (M)
A message storage unit (11) for storing different message data from a plurality of programs installed in communication software for performing communication with the slave station (S);
A message priority determination processing unit (12) for comparing the priority of all messages stored in the message storage unit (11);
A transmission processing unit (14) for transmitting from the message storage unit (11) to the destination device on the slave station side (S) in order from a message with a high degree of urgency according to the urgency level of priority;
When a message with a low priority is stored in the message storage unit (11), an elapsed time after transmission from the plurality of programs for each message is specified for the message with a low priority Is set as the timer value of the message, the elapsed time is counted, and the message that has reached the specified value is sent to the transmission processing unit (14) before the message of high priority stored in the message storage unit (11). Timer count unit (13) to output to
A data transmission system comprising:

Images