JPH0214643A - Data transmission system - Google Patents

Abstract

PURPOSE:To reduce the waiting time of data transmission from a slave station to a master station by providing a polling frame to collect a data with the transmission request in the presence of the data transmission request from a transmission request station. CONSTITUTION:An individual polling frame processing section of a master station processes the information from a slave station designated by an address of its individual polling frame and recognizes the presence of the data transmission request from one slave station or over from a logical value of the data transmission request bit location of the individual polling frame. Then in the case of recognizing the presence of the data transmission request, the presence of the data transmission request station is informed and a frame transmission control section sends a simultaneous polling frame to the data transmission request call station with priority over the individual polling frame. Thus, the wait time of the data transmission from a slave station to the master station is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data transmission system. In particular, the present invention relates to a data transmission method using polling frames in a 1:N type data transmission system in which data transmission devices are connected in a loop and a plurality of N slave stations are connected to a master station.

The present invention can be used for data transmission in a so-called local area network.

〔overview〕

The present invention provides a data transmission method in which data transmission devices are connected in a loop and data is transmitted using polling frames from a master station, in which a data transmission request is sent from a transmission requesting station in addition to an individual polling frame specifying a slave station. By providing a simultaneous polling frame for collecting the data requested for transmission when the data is transmitted, the waiting time for data transmission from the slave station to the master station is shortened.

[Conventional technology]

There is a data transmission system in which a plurality of data transmission devices are connected in a loop, one of the data transmission devices is used as a master station, and the other data transmission devices are used as slave stations, and data is transmitted and received in a 1:N ratio. The polling frame structure for transmitting and receiving data in this conventional data transmission system is as shown in FIG.
, an individual polling section C1 containing control information, a data section 11, a frame check sequence section FC3, and by transmitting this individual polling frame from the master station to the slave station, the address section A1 of the polling frame is The method was to collect data from the slave stations specified in Part C.

[Problem that the invention seeks to solve]

However, in the conventional data transmission method using this individual polling frame method, the polling frame address is specified from the master station to each slave station in turn.
If the transmission frames from a specific slave station to the master station are concatenated, or if the transmission frames from the master station to a particular slave station are consecutive, the slave station in the pond will transmit data to the master station. Even if an attempt was made to send the data, there was a problem in that it would take a long time to transmit the data to the master station.

The present invention solves the above-mentioned problems, and aims to provide a data transmission method that can shorten the waiting time for data transmission from a slave station to a master station, and shorten the time it takes for data to be transmitted to the master station. purpose.

[Means for solving problems]

In the present invention, a plurality of data transmission devices are connected in a loop, one of these data transmission devices is used as a master station, and a polling frame containing an address destined for each slave station is transmitted from the master station to each slave station. In a data transmission method that transmits data by sending data, when the master station receives a transmission request from the slave station, regardless of the address of the polling frame, the station that generated the transmission request sends the data to the master station. A means for transmitting an individual poll+IJ song frame that includes a section containing information instructing a transmission request, and a simultaneous polling frame that carries data to be transmitted to the master station from the transmission request generating station are given priority over the individual polling frame. Each slave station includes means for setting data transmission request instruction information in an individual polling frame when a data transmission request occurs, and means for setting data transmission request instruction information in an individual polling frame when a data transmission request occurs; and means for transmitting to the station.

[Effect]

Individual polling frames destined for each slave station from the current station can contain information to instruct the generation of a data transmission request when a data transmission request occurs at a slave station other than the destination station. There is a time limit of 2 minutes.

The slave station that has generated the data transmission request places information indicating that there is a data transmission request in the data transmission request information section and transmits it to the master station.

The master station determines from the transmission request information of this polling frame that a station requesting data transmission has occurred, and sends a simultaneous polling frame to collect data for the stations requesting data transmission, giving priority to sending individual polling frames. The data transmission requesting station then loads the data to be transmitted into this simultaneous polling frame and transmits it to the master station.

・Two fruits absolutely fall] Embodiments of the present invention will be described below with reference to the drawings.

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

As shown in FIG. 1, the data transmission system of this embodiment includes a master station M301, a slave station 51302, and a slave station Sk'103.
, The system consists of slave stations 5N304 connected in a loop (through a transmission line).

FIG. 2 is a blower diagram showing the configuration of this master station device 301. As shown in FIG. The transmitting/receiving interface section 101 of the master station device is
A simultaneous polling frame processing unit 103 that has a function of sending polling frames to slave stations, receives polling frames from slave stations, and processes simultaneous polling frames for individual polling frame processing units 102 and transmission request generating stations. It has a function to send to each. The polling frame transmission control section 104 generates a polling frame string consisting of the individual polling frames and the simultaneous polling frames from the individual polling frame processing section 102 and the simultaneous polling frame processing section 103, and transmits the polling frames on the transmission path via the transmission/reception interface section 101. Send to.

The individual polling frame processing unit 102 of the master station processes information from the slave station specified by the address of the individual polling frame, and at the same time processes the data transmission request bit (DSRQ, Data) of the individual polling frame.
From the logical value of the position (abbreviation for Send Request), 1
Recognizes whether there is a data transmission request from a slave station or higher.

Note that the data transmission request bit here refers to a data transmission request bit that all slave stations can set in the individual polling frame, regardless of the address (destination of the slave station) of the individual polling frame.

When recognizing the existence of a data transmission request, the individual polling frame processing unit 102 notifies the polling frame transmission control unit 104 of the existence of the data transmission requesting station, and the frame transmission control unit 104 Broadcast polling frames for stations are sent out with priority over individual polling frames.

Further, the simultaneous polling frame processing unit 103 processes data from the transmission request generating station.

FIG. 2 is a block diagram showing the configuration of the slave station of this embodiment.

The transmitting/receiving interface section 201 receives a polling frame sequence from a master station or an adjacent slave station, and transmits it to the next slave station or master station. The polling frame received by this transmitting/receiving interface section 201 is sent to an individual polling frame detecting section 202 and a simultaneous polling frame detecting section 203 that processes a simultaneous polling frame for the transmission request generating station.

The individual polling frame detection unit 202 determines whether the address of the polling frame matches the own address, and notifies the information transmission control unit 204 of the result. The information transmission control unit 204 inserts data if the addresses of the polling frames match. Also, if you are trying to send data even if the addresses do not match, set the data transmission request bit in the polling frame to the logical residue of "transmission request", for example "1", and add a frame check sequence FC3. is corrected and sent to the transmission/reception interface section 201. Further, the simultaneous polling frame detection section 203 detects a simultaneous polling frame for the transmission request generating station and notifies the information transmission control section 204 of the detected simultaneous polling frame. The information communication control unit 204 places the transmission data and information indicating the address of the originating station on the simultaneous polling frame, and performs a frame check sequence FC.
3 is reattached and sent to the transmitting/receiving interface unit 201, and the transmitting/receiving interface unit 201 sends a simultaneous polling frame carrying information for this master station to the next data transmission device, and transmits the data to the master station.

Next, the procedure of data transmission in the transmission system of FIG. 1 will be explained by showing examples of individual polling frames and simultaneous polling frames transmitted from the master station to the slave station and from the slave station to the master station in FIG.

First, the master station 301 transmits an individual polling frame 305 shown in FIG. 4 to the slave station. Compared to the conventional individual polling frame, the individual polling frame 305 shown in (■) has an information transmission request (DSRQ)
The difference is that the bit cleaning position for setting up the bit is provided in front of the atrus part.

The master station sets the logical value of the information transmission request bit of this individual polling frame 305 to "0", sets the address of the destination slave station to 81, and sends out this individual polling frame 305 to the transmission path.

The destination slave station S1 performs normal individual polling frame processing, and if there is data to be sent to the current station, it is placed in the data section of this frame, and if there is no data, it is sent to the next slave station without putting data in the data section. This individual polling frame is sent to

When a data transmission request occurs in the slave station Sk, the logical value of the information transmission request bit of the individual polling frame whose destination address is 81 is set to "1", and the data transmission request is sent to the next slave station as the individual polling frame shown in FIG. Send to.

The master station receives the frame ■ in which the bit indicating the occurrence of a transmission request is set, recognizes that a station requesting data transmission has occurred, and sends a simultaneous polling frame to the stations requesting data transmission via the polling frame transmission control unit. 306 is sent.

This simultaneous polling frame 306 has a specific code (AI
shall be. ), and the control information of the individual polling section is set to the code (C1) indicating simultaneous polling in Fig. 4■
It is transmitted to the slave station as a polling frame with the following configuration.

When the slave station 5k303, which is a data transmission requesting station, receives this simultaneous polling frame ■, its simultaneous polling frame detection unit detects the simultaneous polling frame, and the information transmission control unit 204 transmits the transmission data to information indicating the originating station. It is also placed in the data section I of this simultaneous polling frame and transmitted to the master station as the polling frame shown in FIG.

The master station receives the simultaneous polling frame (2) containing data from the data transmission request generating station, and receives and receives data from the data transmission request generating station.

When there are data transmission requests from multiple slave stations, since this simultaneous polling frame is composed of a variable-length data section 11, the multiple data transmission request generating stations sequentially transmit the data to be transmitted to the master station. and data indicating the originating station are added to the data section of the simultaneous polling frame, and the simultaneous polling frame is transmitted to the master station. Therefore, by transmitting one simultaneous polling frame, the master station can collect transmission request data at once even if there are a plurality of slave stations requesting data transmission.

〔Effect of the invention〕

As explained above, in a data transmission system that performs 1:N data transmission and reception between a plurality of data transmission devices connected in a loop, the present invention provides a data transmission request that is made separately from an individual polling frame addressed to each slave station. Since simultaneous polling frames are used to collect data only from the generating station in preference to individual polling frames, when a data transmission request is made to a slave station, the waiting time for data transmission to the master station is reduced. This has the effect of shortening the time it takes for the information to be transmitted to the master station, and has the advantage that the local station can respond more quickly.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a transmission system according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the master station device according to the embodiment. FIG. 3 is a block diagram showing the configuration of the slave station device according to the embodiment. FIG. 4 is a diagram showing the configuration of a polling frame in the embodiment. FIG. 5 is a configuration diagram of a conventional polling frame. 301... Master station, 302.303.304... Slave station, 101.201... Transmission/reception interface section, 1
02... Individual poll link processing section, 103... All at once polling frame processing section, 104... Polling frame transmission control section, 202... Individual polling frame detection section, 203... All at once polling frame detection section,
204... Information transmission control unit, 305... Individual polling frame, 306... Simultaneous polling frame.

Claims (1)

[Claims] 1. A plurality of data transmission devices are connected in a loop, one of these data transmission devices is used as a master station, and a polling frame containing an address addressed to each slave station from the master station is sent. In a data transmission method in which data is transmitted by sending data to each slave station, when the master station receives a transmission request from the slave station regardless of the address of the polling frame, the transmission request generating station means for transmitting an individual polling frame including a part containing information instructing a data transmission request to the station, and a simultaneous polling frame carrying data to be transmitted to the master station for the transmission request generating station over the individual polling frame. and a means for setting data transmission request instruction information in an individual polling frame when a data transmission request occurs, and a means for setting information to be transmitted in the simultaneous polling frame in each slave station. A data transmission method characterized by comprising: means for transmitting data to a master station.