JP2000286923A - Communication system and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system/method which adds the time information of the transmitting side to the transmission information and can attain accurate processing and decision against processing and transmission abnormalities which are detected at the receiving side. SOLUTION: In this transmission method, a 1st station 101 of the transmitting side adds the time information counted by a timer 12 of the station 101 to the transmission information to be originally transmitted and transmits these information to a 2nd station 102 of the receiving side. Thus, the station 102 can accurately grasp the time change of the transmission information for the control processing, etc. to be performed to decide the time change of the transmission information. Thereby accurate processing is secured at the station 102. Furthermore, it is possible to surely decide the presence or absence of transmission abnormalities between both stations 101 and 102 from the contents of the received time information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication method and a communication system for a communication system in which information is transmitted between a plurality of stations at a constant period, and more particularly to a method for adding transmission source time information to transmission information. The present invention relates to a communication method and a communication system of a communication system provided for processing on a receiving side and transmission abnormality detection.

[0002]

2. Description of the Related Art Conventionally, as a communication system for transmitting information between a plurality of stations at a constant period, for example, there is a communication system as shown in FIG. In FIG. 1, the communication system of the conventional example performs information transmission between a first station 201 and a second station 202, and the first station 201 includes a first communication circuit 211 for transmitting and receiving information. The second station 202 includes a second communication circuit 211 for transmitting and receiving information and a CPU 222 for generating transmission information and processing received information.
And the second station 202 are connected by transmission means 203 such as a cable. Here, an example of information transmission,
That is, a servomotor control system is considered as one application form of the communication system of the conventional example. In this case, the first station 201 has position detecting means such as an encoder connected to the first communication circuit 211, and the second station 202 has C
The configuration is such that a driving unit such as a servo driver incorporating the PU 222 is provided. The servomotor is driven by the drive unit based on a predetermined command given to the CPU 222. At this time, the position information of the servomotor detected by the position detection unit is transmitted to the first communication circuit 211 and the transmission unit 20.
The signal is fed back to the CPU 222 via the third communication circuit 221 and the second communication circuit 221, and is used for control of the servomotor by the CPU 222.

[0003]

However, when the communication method and the communication system of the conventional communication system are applied to the servo control system, the communication from the first communication circuit 211 of the first station 201 is performed at regular intervals. The position information and the like detected by the position detecting means are used as transmission information in the second station 20.
The transmission error is transmitted to the second station 202, but the second station 202 only performs a sum check or the like of the received transmission information as the transmission abnormality detection performed when the second station 202 receives the transmission error. If the first station 201 and the second station 202 are not synchronized, the second station 2
On the other hand, on the 02 side, the transmission information is read in the middle or the previous transmission information is read, so that accurate information cannot be obtained on the receiving side and accurate information cannot be provided for processing such as control. There were also points. The present invention has been made in view of the above-described conventional circumstances and problems, and adds time information of a transmission source to transmission information, and provides the time information to processing on the receiving side and transmission error detection. It is an object of the present invention to provide a communication method and a communication system for a communication system capable of performing accurate processing and judgment.

[0004]

In order to solve the above-mentioned problems, a communication method for a communication system according to a first aspect of the present invention provides a communication method for a communication system in which information is transmitted at a fixed period between a plurality of stations. In the method, when information is transmitted from one station to another station, the time information measured by the one station is added to the information and transmitted to the other station, and transmission abnormality confirmation and control are performed. And so on. Further, the communication system according to claim 2 is a communication system in which communication is performed between a plurality of stations at a fixed period, wherein the plurality of stations each include a clock that counts a time peculiar to the station or a timer that measures time. Equipped, when transmitting information from one station to another station, transmitting the information to the other station by adding time information based on the clock or the clock means of the one station, transmission This is for checking and controlling abnormalities.

In the communication method of the communication system according to the first aspect of the present invention and the communication system according to the second aspect, when information is transmitted from one station to another at a fixed period between a plurality of stations. The transmission information that the transmission source should originally transmit, adding time information based on the clock of the transmission source station or time information measured by the timer means and transmitting the transmission information to the transmission destination station, and confirming and controlling transmission abnormalities, etc. To do. As a result, it is possible to accurately grasp the time change of the transmission information on the receiving side (the transmission destination station) and accurately perform processing such as control. Also,
Since the time information is more predictable on the receiving side than the transmission information that should be transmitted, it is necessary to reliably determine whether a transmission error has occurred based on the content of the received time information. Can be.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a communication method and an embodiment of a communication system according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of a communication system according to an embodiment of the present invention, which is a communication system to which the communication method of the present invention is applied. In the figure, the communication system of the present embodiment includes a first station 101 and a second station 102.
The first station 101 includes a first communication circuit 11 for transmitting and receiving information and a first station 101.
The second station 102 includes a second communication circuit 21 for transmitting and receiving information, and a CPU 22 for generating transmission information, processing received information, and the like.
In this configuration, a first station 101 and a second station 102 are connected by transmission means 103 such as a cable.

In the communication system of this embodiment, when information is transmitted from the first station 101 to the second station 102 at a fixed period, the first station 101 of the transmission source adds first information to the transmission information to be originally transmitted. It is characterized in that the time information measured by the timer 12 of the station 101 is added and transmitted to the second station 102 of the transmission destination. This allows the receiving side (second station 102) to accurately grasp the time change of the transmission information and to provide processing such as control for obtaining the time change of the transmission information. Can be performed accurately. Also, the time information to be added can be compared with the transmission information to be transmitted from the first station 101 to the second station 102 and the time information by a clock (not shown) in the receiving side (the second station 102). , Etc., the information can be predicted on the receiving side.
It is possible to reliably determine whether or not a transmission error has occurred in the information transmission between the station 101 and the second station 102.

Next, as in the conventional example, a servomotor control system will be considered as a specific application of the communication system of the present embodiment. In this case, on the first station 101 side,
The second station 102 is provided with position detecting means such as an encoder connected to the first communication circuit 11 and driving means such as a servo driver incorporating the CPU 22 on the second station 102 side.
The servomotor is driven by the driving unit based on a predetermined command given to the CPU 22. At this time, the position information of the servomotor detected by the position detecting unit is stored in the first position.
Communication circuit 11, transmission means 103 and second communication circuit 21
Is fed back to the CPU 22 via the CPU 22 to control the servo motor by the CPU 22.

At this time, when the communication system of this embodiment is applied, when transmitting the position information from the first communication circuit 11 of the first station 101 to the second communication circuit 21 of the second station 102, The transmission is performed in a transmission format in which the time information measured by the timer 12 of the first station 101 is added to the position information. That is, the first communication circuit 11 transmits time information, position information, and information such as a sum by the timer 12 at regular intervals. On the other hand, the second communication circuit 21 of the second station 102 first performs a sum check, a format check, and the like, and reads from the middle of the transmission information or determines whether or not the previous transmission information has been read from the time information received. Then, based on the time information, it is determined whether or not an abnormality has occurred in the transmission between the first station 101 and the second station 102. Here, as one of the detections of the transmission abnormality, a time difference is obtained from the time information received last time and the time information received this time, and if the time difference is zero, it is determined that the transmission is abnormal. In addition, when the receiving side (second station 102) is provided with a timer or the like, or when the transmission cycle is known,
When the time difference is equal to or smaller than a predetermined threshold, the transmitting side (first
It is also possible to estimate that a hardware failure or the like has occurred in the timer 12 or the like of the station 101).

Next, the CPU 22 of the second station 102 determines the speed from the position information and time information received last time and the position information and time information received this time.
Is used for servo motor control. Here, the speed can be obtained by “(change amount of position information) / (time difference)”. Note that the first station 101 and the second station 102
When the synchronization is established between the first station 201 and the second station 202, if the synchronization is established between the first station 201 and the second station 202, the reception may be performed as it is according to the synchronization signal or the like. By adopting the same information twice in succession, processing such as abnormality detection and control may be performed in a similar manner.

[0011]

As described above, according to the communication method and the communication system of the communication system of the present invention, when information is transmitted from one station to another at a fixed period between a plurality of stations. In addition, the transmission source should transmit the transmission information to be transmitted originally, adding time information based on the clock of the transmission source station or time information measured by the timer means, and perform transmission abnormality confirmation and control. Therefore, the receiving side (destination station) can accurately grasp the time change of the transmission information and accurately perform processing such as control, and a transmission error occurs based on the content of the received time information. It is possible to provide a communication method and a communication system of a communication system capable of reliably determining whether or not the communication is performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a communication system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional communication system for transmitting information at a fixed period between a plurality of stations.

[Explanation of symbols]

 101, 201 First station 102, 202 Second station 103, 203 Transmission means 11, 211 First communication circuit 12 Timer 21, 221 Second communication circuit 222 CPU

Claims (2)

[Claims] In a communication method of a communication system for transmitting information at a fixed period between a plurality of stations, when transmitting information from one station to another station, said information is transmitted to said one station by said one station. A communication method for a communication system, comprising adding timed time information and transmitting the time information to the other station to check and control transmission abnormality. 2. A communication system for performing communication at a fixed period between a plurality of stations, wherein each of the plurality of stations has a clock for counting a time peculiar to the station or a clock means for measuring time. When transmitting information from another station to the other station, the time information based on the clock or the clock means of the one station is added to the information and transmitted to the other station, and transmission abnormality confirmation and control, etc. A communication system characterized by performing: