JPS60103847A - Method for controlling communication transmission - Google Patents

Abstract

PURPOSE:To offer communication transmission control method detecting quickly abnormality of communication function due to a fault by making communication confirming the operation of a device with low communication frequency through the use of an idle time of a line. CONSTITUTION:When a state change 1B takes place, a start request is inputted to a transmission request generating circuit 12. A communication control circuit 10 supervises a signal on a transmission medium (a) via a superimposition detecting circuit 7 and a reception circuit 8 by a signal from the transmission request generating circuit 12. In monitoring the state supervision of all terminal devices, a station A supervises a transmission medium by a time t3 and when no signal exists on the medium, a state supervisory packet 5 is transmitted. When a station C has a transmission request 1C during the transmission of the state supervision packet 5, the station C starts supervision of the transmission medium. When the content of the transmission by the station C is a data packet, the station C continues supervision until an idle time on the medium becomes t1 and when the idle time becomes t1, the transmission of a data packet 2 is started. Even if all terminal devices are supervised, the data packet is transmitted with priority by providing priority to each packet in this way.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is for communication transmission between decentralized devices! 1
This is related to the JlJ control method.

Conventional configurations and their problems Methods for controlling communication transmission between decentralized devices or between devices and sensors can be roughly divided into two types. One of them is a centralized communication transmission control method,
This is a master-slave type, in which the master has all transmission control rights and collects information from slave stations by polling. This method uses slave station transmission t
The advantage is that the algorithm can be easily implemented, and if polling is always performed, even if an abnormality occurs in the slave station's communication function, it can be immediately stopped.

However, the centralized communication transmission control method has poor expandability, and the transmission control m+ algorithm of the master station must be changed as the number of slave stations increases. Furthermore, since the master manages the 11-share deposit rights, there is a drawback that if the master's function stops, communication with the slave stations will be interrupted and the system will go down.

The other is the distributed communication transmission: U 111 method, which (
In this system, all stations have distributed transmission control algorithms, regardless of whether they are masters or slaves, and the control authority is also entrusted to the station that wants to start communication.

This method has the disadvantage of being expensive because all stations must have a transmission control algorithm, but it is scalable and
It is excellent in risk distribution, etc., and can be said to be optimal for systems that require scalability and reliability such as security.

However, since the distributed communication transmission method generally performs communication based on transmission requests from distributed terminals, it is not safe to perform a bow link itself. death.

Therefore, it is not known whether the communication functions of each station can operate properly until each station starts transmitting data. Figure 1 shows this situation. A, B, C
, D represents the transmitted signal of that station, and E
represents the signal on the transmission medium. When transmission request 1 occurs at station B, it monitors signal E on the t-straddling medium,
If there is no data packet 2' (c
- Send (in FIG. 1, station B is transmitting to station A). The receiving station transmits the signal on the t-spanning medium to 4i.
(1+' is recognized, and if there is no signal, the received 4i11f magazine packet 3 is returned. Here, the n VC7JE is received. A transmission request 1 is generated at D, and data packet 2 is sent.

If there is an abnormality in the transmitter at this time, the abnormality can be discovered for the first time.

This has the disadvantage that an abnormality can only be detected when a Ci alarm occurs, unlike a security sensor that rarely performs an alarm operation all the time and only communicates in the event of a fire or gas leak.

Purpose of the Invention The present invention provides a distributed Jm system that is excellent in expandability and risk distribution.
It is an object of the present invention to provide a communication transmission control method that can quickly detect abnormalities due to failures in the communication function as described above, even though the communication method is used.

Composition of the Invention Unexploited BJJ is composed of at least one pair of communication media and a number of equipment VCs connected to each other through the ILl'l'l'l'l'l'l medium, and in order to (confirm) the operation of the equipment that communicates infrequently, The infrequent operation of the device is performed using the free time of
(r(+r ii) All communications to be carried out are carried out.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows a block diagram of a terminal using the distributed communication transmission control method according to the present invention.

a is a transmission medium, b is a received signal, C is a received signal, 7VJ superimposition detection circuit, 8 is a reception circuit, 9-digit transmission circuit, 1Q is a communication control circuit, 11 is a timer circuit, and 12 is a transmission request generation circuit.

A case in which the other station is changed to VCtL due to a change in the state of the end of ψ;111 will be explained with reference to FIGS. 2 and 3. Each terminal has a configuration as shown in FIG. 2, and when a change in status 1B occurs, an activation request is input to the transmission request generation circuit 12. Communication 11' control circuit 1o is transmitting 1. The signal from the stability generation circuit 12 causes the superposition detection circuit 7. The signal on transmission medium a is monitored via eight receiving circuits. If there is no signal on the transmission medium a, the clock signal from the timer 1+-1 path 11 monitors the transmission medium for a time period of -IK" (tl),
If there is no signal on the transmission medium during that time, data packet 2 is sent out. In FIG. 3, station B sends a data packet to station A. Station A sends the data packet to the communication terminal via the superimposition detection circuit 7 and reception circuit 8.
If there is no reception error in the J side 1 circuit 10, the clock signal from the timer circuit 11 causes the time (t
2) The transmission medium is monitored, and if there is no signal on the transmission medium during that time, a reception confirmation packet is sent.

Next, when monitoring the status of all terminals, station A travels on the transmission medium for (t3) time! ii;;+, if there is no signal on the congratulatory medium, transmit the status monitoring packet 6; Condition ① Monitoring When station 0 receives a transmission request 1C while packet 5 is being transmitted, station 0 starts monitoring the transmission medium. If the transmission content of the 0th station is a data packet, the difference is that the 0th station is idle time on the medium (tl
), the transmission of data packet 2 is started when the idle time (tl) is reached.

here, t2 < t, < t,.

The difference is that the packet priorities are 1 reception confirmation packet, 2 data bucket, and 3 states! , becomes a small monitor packet.

JL with a large number of terminals and not trying to monitor all terminal status.
It takes a long time to trace the medium and fortune-telling, but Ai
By assigning a priority to each packet as described above, data packets can be transmitted preferentially even if the status of all terminals is not being monitored.

By following the above procedure to perform transmission 11111 l'i11 and monitor the status at regular intervals, you can check whether there is any abnormality in the communication function of the device without interfering with normal data transmission. 1) I can do that.

Effects of the Invention The present invention not only improves the communication function of equipment that constantly communicates, but also supports the communication function of equipment that does not issue alarms at all, such as a security sensor (11). [In order to conduct the magazine, there was no such thing as a communication failure in the emergency I+, -, and a security incident or I/11.
, - The effect of C1 is large for systems that require axiality.

[Brief explanation of the drawing]

Claims (1)

[Claims] It is a communication transmission control method that performs distributed communication control between each device, and starts communication when a communication request is generated within the device.
A communication transmission control method characterized in that polling is performed in a priority order that does not interfere with communication due to communication requests.