JPS58150345A - Loop-shaped data transmission method - Google Patents

Abstract

PURPOSE:To improve the efficiency of transmission, by transferring immediately the transmission right to the next station when no transmisson data of own station exists, therefore, occupying the transmission line with the transmission data at all times. CONSTITUTION:A central control station SVC is connected to plural slave stations ST1-STn in a loop shape with a single transmission line DL to perform the mutual transfer of data. The transmission frame which is transmitted by the station SVC contains a high-speed scan instruction, a low-speed scan instruction, a low-speed scan discontinuation instruction and a low-speed scan start instruction. When a transmission permitting token is contained in the receiving signal of a transmission frame which is sent from an upstream station and received by a slave station, the transmission data of own station corresponding to a high- speed or low-speed scan mode is transmitted to a downstream station with a transmission frame which contains no transmission permitting token. When the transmission frame is received at the own station after a rounding of the loop, the transmission permitting token is contained in the transmission frame and them transmitted to a downstream station.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a data transmission method, and more particularly to a loop data transmission method in which each station sequentially transmits data in a broadcast mode of high-speed scanning and slow-scanning according to instructions from a central management station.

b. Prior Art Conventional % When each station uses a single loop-shaped transmission line in common in a time-division manner, there are two methods for determining the station that occupies the line: a fixed assignment method and a polling method.

The fixed allocation method is a method in which one frame is divided, each divided time slot is fixedly allocated to each station, and each station transmits its own data in its own slot. This method has the disadvantage that each station always occupies a certain amount of time on the line even when there is no data to be transmitted, so there are times when the line is not transmitting data, and the data transmission efficiency of the line is very poor.

On the other hand, in the polling method, the line-occupying stations are managed by a central management station (hereinafter referred to simply as the central station).When the line becomes clear, the central station sends a polling command to the transmission loop in order to search for a slave station that has a transmission request. Send.

When each slave station receives this polling command, the slave station that has data to transmit returns its own station name address and transmission priority level to the central station. The central station polls and sends the next select command with the name of the slave station occupying the line. The slave station that receives this exclusive slave station name obtains the right to transmit subsequent data, sends data to the line, and when the data transmission is completed, notifies the central station that the line is open with a completion command. In this polling method, the transmission of control commands such as polling commands, select commands, and completion commands frequently occupies the line.
The disadvantage is that the data transmission efficiency of the b-line becomes poor.

C. OBJECTS OF THE INVENTION An object of the present invention is to provide a loop data transmission method that increases transmission efficiency by making effective use of data transmission paths.

d. Configuration of the Invention FIG. 1 is a schematic configuration diagram of a data transmission system to which the loop data transmission method of the invention is applied.

Central management station SvC and multiple (n) foals 8T, ~8Tn
are connected in a loop through one transmission path DL, and data is exchanged between them.

Figure 2 shows a central control station 8VC (hereinafter simply referred to as 8V, 0 station) and a plurality of (n) slave stations 8Tl to 8 configured as the 11th EI.
T11 (hereinafter single IC 14 Tl ~ a T n
It is a rounding 06 production timing diagram explaining the operation of the station.

In the figure, (1) indicates the time slot of each transmission frame based on the avcjIo transmission end. The same figure (C) is S
Indicates the state of the transmission frame transmitted from the MC station, (d
) ~ Ig) are 8Tl ~ aTn with a little time delay.
The same figure (
b) shows a transmission frame transmitted from the STn station and received by the SMC station.

FIG. 3 is a detailed diagram of the above transmission frame, which is composed of [frame 5 synchronization flag] + [command word] + [transmission station name] + C data].

In the #l frame time slot of Figure (a), the SMC station transmits #l which includes the command words of slow scan mode ■ and transmission permission token ■, as shown in Figure 2(C).
Send the frame to the 8T1 station. 8T, station is command word■
■Detects and determines whether there is data to be transmitted by the local station by low-speed scanning. If there is no data, simply send 8T to the station without changing the command word ■■ as shown in Figure 2 (d). Relay. 8T, the station detects the command word ■■, determines whether it has data to transmit by slow scanning, and if so, changes the transmission permission token from ■ to @ as shown in Figure 2 (e). Then, the command word ■■, transmitting station '41'#2, and low-speed scan transmission data are placed on this #1 frame and transmitted to the STs station.

ST, the station detects the command ■, and the own station goes into relay mode.
The received 9 frames are simply forwarded and sent to the 8T4 station, and at the same time, the low-speed scan data reception memo IJK for the busy own station #2 is stored. The following 8T, ~8Tn stations similarly detect the command [stock], store the transmission data from the 8T station in their own low-speed scan data reception memory for station #2, and relay the frame signal to the downstream station. .

The transmission data #2 from the ST relayed by the 8Tn station shown in Fig. 2(x) reaches the receiving end of the 870 station as shown in Fig. 2(b). The received frame of 5vCsI is delayed, and from the time when the #1 frame is completely transmitted in the #1 frame time slot, the #2 frame is transmitted from the station as shown in Fig. 2(e). The data frame is relayed and sent to 8T. At this time, the SvC station adds a command word ■ indicating that the low-speed scan is to be interrupted, and sends it to the station for 8T.

The 8T station detects the command word ■ and stores it in its own low-speed scan data reception memory for station #2, and at the same time relays this frame and transmits it to the 8T station. Thus, the data broadcasted by the 8T station is stored in the slow scan data reception memory for $2jij of all stages except the aTs station.

Now, when the frame is received at 8T, the station receives 19T,
The station detects that the nine data transmitted by itself have completed one cycle, changes the command word of this frame to ■■■, and transmits it to the station at 8T. 8T, the station detects that the command ■ is in this frame, and even though the command word is ■■, this command ■■
② is relayed to the single KIT station. (If there is no command ■, it will be in normal operation mode, 8T, if the station has low-speed transmission data, it will be a command ■■, and the transmitting station building #3 and the transmission data will be placed on this frame, but in the current case, the command is because it is a ■ command. ■■■
to be relayed. ) The 8T3 station now detects the command ■■■ and stores a slow scan transmission permission token at the ninth point to remember that the transmission board has been interrupted. 8T.

~8Tn The station similarly relays the command ■■■ and stores the slow scan transmission permission token at the same time as transmitting it to the downstream station.

The 870 station interrupts the low-speed scan mode from the #3 frame time slot in Figure 2-) when it finishes transmitting the #2 frame of the ST the command ■■ as in (C)
Send to 1 station. The ST1 station detects the command ``■■'' and determines whether there is any data that its own station transmits by high-speed scanning, and if there is not, it does not change the command ``■■'' as shown in Figure 2 (d). 8T, relay transmission to the station. ST detects the command ■■, judges whether there is data to be transmitted by high-speed scanning, and if there is, sends a transmission permission token as shown in Figure 2 (e). ■Order changed to prayer■■ and transmitting station name#
Put the 2-tone high-speed scan transmission data on this frame and send 8
T, 1it) Send K. 8'f', -8T1 station detects the ■ command, knows that it is in relay mode, simply relays the received frame and transmits it to the downstream station, and at the same time #2
Stored in high-speed scan data reception memory for the station. Thus, the nine high-speed scan transmission data broadcast from the aTs station are stored in the high-speed scan data reception memory for station #2 of all stations.

Now, when the frame sent from the 8T station comes around and is received by the 8T station, the 8T station changes the command word to [Yes] ■ and sends it to 8T, 4. Then, pass the transmission permission token to the station at 8T. If there is sT, 4 < high-speed scan transmission data, at 8T, the station changes the command to ■(!?
Transmitting station name #3 and transmission data are placed on this frame and transmitted. This 8T broadcast data from the station goes around each station and returns to the STs station again. During this cycle, the transmission data of each station is stored in the high speed scan data reception memo IJK for #3 of each station. Thereafter, in the same manner, the station that detects the transmission permission token sends high-speed scan transmission data, and all stations that receive this data store it in the high-speed scan data reception memory for that transmitting station.

In this way, 8T4 to 8Tn1i6IC transmission permission tokens are sent, and finally K STn station sends 8Tn1i6IC transmission permission tokens to 8T4 to 8Tn1i6IC transmission permission tokens.
1SvC when the aTn station sends the command ■■ to be passed to the 70th station.
The station detects this command, interrupts the high-speed scan mode in the #l frame time slot as shown in Figure 2 (C), changes to the low-speed scan mode again, and sets the command word ■■■ to 8it.
Send to station. ■ is an instruction code for polling/resuming slow scan.

8T1 station detects that the command ■ is in this frame,
These instructions are simply 8T even though they are instructions.
, relay transmission to the station (If there is no command ■, it will be in normal operation mode. If the 8it station has the low-speed scan transmission data, it will be the command ■) and put the transmitting station name #1 and low-speed scan transmission data in this frame. In this case ■ Rounding of commands, commands ■
Relay ■■. ) 8T, the station similarly simply relays and stores the command ■■■ to the 8T, station. Holds a slow scan transmission permission token. 8T and M6 that have this token detect the command ■■■, determine whether their own station transmits in slow scan mode and have round data, and if so, see Figure 2 (
Enter the sending permission token as ■ or cJ9w** as in f),
Place the command word ■■ [stock], transmitting station name #3, and low-speed scan transmission data on the #f frame and transmit it to the station at 8T. (If there is no low-speed scan transmission data at 8T, the station simply relays the command 1 to carry its own station's transmission data.) When the 8T4 station detects the command ■■■, it simply relays this frame to the downstream station, and at the same time stores it in the low-speed scan data reception memory for the #3 station. Before Nine #2
Resets the slow scan transmission permission token stored in the frame time slot.

Thereafter, the 8 Tl-8T n station similarly detects the command ■Φ9, simply relays this frame to the downstream station, and at the same time stores it in its own low-speed scan data reception memory for station #3, and also uses the previously stored low-speed scan data. Reset the scan send permission token. This 8T has the transmitted data from the station #
1' frame is transmitted from the 8Tn station to the 8VCNJQ receiving end as the second frame.
It is reached as shown in Figure (b).

The SVC station delays this received frame and relays this received frame ■■■#3 to the station for 8T as the #2 frame from the time when the #l frame has been completely transmitted from 5vc4 in the #1' frame time slot. Send, but this #i
In the frame time slot, 8 VC stations are ordinary low-speed scan mode frames except for the instruction code ■ [stock]
#3 sends 8T to the station. This #i frame is 8T1
It is relayed and transmitted by the station, 8T, and #3 of each own station.
Stored in the station low-speed scan data reception memory. aT
When one station receives this #i frame, it detects that its own station transmission data has been broadcasted to all stations, changes the command word of this frame to ■■, and passes the low-speed scan transmission permission token to the downstream station. 8T, a station with medium-to-low speed scan transmission data of downstream stations below the station receives this token and returns to the normal low-speed scan mode for broadcast transmission, which is the same mode as #1 frame time slot in the first explanation.

Now, in the timing diagram in Figure 2, the SVC station operates to determine the high-speed scan mode and the low-speed scan mode, and the time from any high-speed scan mode to the next high-speed scan mode is a fixed period. K so that it becomes. During this fixed period, even if all the stations 57 (8T1 stations to 5Tfi stations) have high-speed scan transmission data, the time required for transmitting the Kn frame is set so that all stations are serviced.

To summarize the operation of the SVC station, the command word ■■ is issued for frames at regular intervals, and the command word [Yes] is issued for the next frame.
From now on, when [Yes] ■ is received at the receiving end of the 810 station, the command word ■■■ is output, and when the above-mentioned fixed period comes, the command word ■■ is output in that frame. The received frame may be delayed and continuously relayed to the next transmitted frame time slot.

f Examples of the invention FIG. 4 shows an embodiment of the configuration of a slave station according to the present invention.

When serial data having the format of one frame as shown in FIG. 3 is received as received data 1, the flag detector 2 detects the frame synchronization flag at the beginning of the frame and initializes the timing generator 3. The timing generator 3 generates a timing signal for determining the bit position of the serial data bit [shown in Figure 83] ~ ■ time slot, ■ time slot, Φ time slot to the logic circuit 8.
Output to. First, when the instruction word ■t- is received in the time slot ■, this is stored in the flip-flop 4, and the instruction word ■■■ is sent to the flip-flop 5, 6.
is stored until the next frame. These held nine command words are input to the logic circuit 8 as state signals, and the operation is performed as follows depending on the combination of command words.

(1) When receiving the command word ■■ When receiving the command word ■ in the time slot, make a verbal judgment,
If there is a request, the output of the logic circuit 8 "!' becomes 111 in this time slot, and the exclusive OR circuit (hereinafter referred to as mx-oa circuit) 10 outputs the inverted signal ■t of the received data ■. Send to transmission data 15.
Transmission FF9 that remembers that the own station is transmitting at this time
Set. In the next ■ time slot, the output 1bI of the logic circuit 8 becomes 111 K, and the own station bases 1 and 2 are ANDed.
It is transmitted through the circuit 11 and the OR circuit 14. At this time, the gate of the AND circuit 21 is closed by the inverter 23. In the next ■ time slot, the output of logic circuit 8 -d
l becomes Jl and high-speed scan memory 1 of common memory 17
AND circuit 13 transmits the transmission data of the own station address part of 7H.
, is transmitted through the OR circuit 14. At this time, the gate of the AND circuit 21 is closed by the inverter 22.

Here, to summarize the configuration of the common memory F, the memory 17 has memory areas for each station, one for the high-speed scan memory 1F and one for the low-speed scan memory 17L, as shown in FIG. The memory area that matches the station number of your own station contains data for transmission by your own station, and the memory areas for other station numbers contain high-speed scan data reception memory and low-speed scan data reception memory that receive transmission data from other stations. will be re-allocated to.

The contents of this memory 17 are exchanged with an external device via an interface (not shown), and after writing own station transmission data into the memory 17, a high-speed scan transmission request signal 18. Alternatively, a low-speed scan transmission request signal 19 is issued.

Further, the low-speed scan data reception memory in which the latest transmission data of all other stations is stored is read out via the interface.

Now, going back to the previous step, if the high-speed scan transmission request signal 18 does not issue a request, the output 1a of the logic circuit 8 @
becomes 101 in the ■ time slot, and the received command word ■ is relayed without being changed to 1. In the subsequent ■■ time slots, the relay mode is adopted, and the transmitted data in this O[present] part is ignored by the downstream station. be done.

(U) When the transmitting FF 9 receives the command word [share] 9 at the time of reset, ■When the command time is received in the time slot, the @aI output of the logic circuit 8 is IQ?・The next command # [share] is relayed and the serial data of the following timeslots and ■timeslots are also sent to EX-OR circuit 1O1AND circuit 2
1. The signal is relayed and transmitted through the OR circuit 14. At this time,
Q time slot) f The transmitting station name shown in Figure 3 is detected in the address register 16, and the address register 16 is stored in the common memory 1.
] Specify the address corresponding to the transmitting station name of 17 and send the primary @
Write high-speed scan data to the high-speed scan memory 17HK of the common memory 17 specified by the time slot.

(III) When the transmitting FF9 is set, when the command word ■■ is received, the transmitting FF9 is reset in the ■ time slot, and at the same time, the command 1 deaf is changed to ■ and transmitted. In the O ■ time slot, the relay mode is used, but the transmission in this part is meaningless to the downstream station.

(If/) When the command word ■■ is received, the same operation as in item (1) is performed with the command word ■ changed to ■ and the high speed scan changed to the low speed scan.

(V) When the transmission FF receives the command word ■■ when it is reset, the same operation as in item (n) is performed with the command word ■t■ replaced and the high-speed scan changed to the low-speed scan now.

(Vl) When the transmitting FF is set and the command word ■θ is received, the command word ■ is replaced with ■ and the same operation as in (1) is performed.

[■] When receiving the command word ■■■, it transmits the command word ■ in the time slot and sets the low-speed scan transmission permission token FF20. Subsequent G
Time slot x takes the relay mode, but this part is meaningless for downstream stations.

[■] Sending FF9 receives command word ■■■ at reset □□
When sending a message, ■ send the command -〇 in the time slot for that tt and the subsequent (
The serial data of iD (ρ time slot is relayed and transmitted. At this time, the transmitting station name is entered in the address register 16 in the J time slot, and the low speed scan data is transferred to the address register 16 in the next O time slot. Write to memory 17L.

(When EKJ fs my FF9 is set, the command word ■■ [stock]
When receiving , reverse command lle in the time slot and send 9■,
Also, the transmission FF9 is reset. The O ■ time slot takes the relay mode, but this part is meaningless for downstream stations.

(X)■Talk/F〆source/' When the command word ■■■ is received at the time of setting, ■the command word ■ is sent in the time slot until that time.[Yes]■
Although the time slot is in relay mode, the jin part is meaningless for downstream stations.

(EK'3■ When the command word ■■■ is received when setting the token F mode, if the command word ■ is detected in the time slot and the low-speed scan transmission request signal 19 is requesting, the logic circuit 8 outputs " Set a゛ to 1゛, invert the command word ■ to ■, transmit it, set the transmission FF9, and reset the low-speed scan transmission permission token FP20.

In the next m time slot, the local station base 12 is transmitted, and in the O time slot, the data for local transmission from the slump scan memory 1)L of the common memory 1 block is transmitted through the AND circuit 13.

Further, if the low-speed scan transmission request signal 19 does not issue a request, the command word (2) is relayed as is and the low-speed scan transmission permission token PF20 is reset. Next guy DO
The relay mode is used in the time slot, but this part is meaningless for downstream stations.

l] When the command word ■■■ is received.

The command word (2) is relayed as it is in the (2) time slot, the low-speed scan transmission permission token FF20 is reset, and thereafter, the command word (3) is transmitted in the relay mode in the (0) time slot. At the same time ■ The transmitting station name of the time slot is set in the address register 16 &
C. The received data of the next time slot is written to the low-speed scan memory 17L of the common memory 17 specified by the address register 16.

g. Effects of the Invention According to the loop data transmission method of the present invention, all stations are always given one opportunity to transmit high-speed scan data in high-speed scan mode at regular intervals, and the high-speed scan data transmitted in high-speed scan mode is If not, 1! This study aims to provide a loop data transmission method in which the transmission right is immediately passed to the next station and an opportunity is given to transmit the low-speed scan data in the low-speed scan mode, thereby improving transmission efficiency.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of the loop data transmission method of the present invention, FIG. 2 is a timing diagram thereof, FIG. 3 is a detailed diagram of a transmission frame, and FIG. 4 is a diagram of a slave station according to the present invention. It is a figure showing an example. 1...9 [data 3...timing generator 8
...Logic circuit 9...Transmission FF12...
・ Own station base 15... Transmission data 16...
Address register 17...Common memory 1B...
■Send request 19... ■Send request 20...
■Token FP (7317) Agent Patent Attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 3 Solt Slot

Claims (1)

[Claims] In a loop data transmission method in which a central management station and a plurality of slave stations are connected in a loop through a data transmission path and mutually exchange data, a high-speed scan mode is instructed to a transmission frame sent by the central management station. a high-speed scan command that instructs a low-speed scan mode, a low-speed scan interrupt command that instructs to interrupt the low-speed scan in the transmission frame immediately before switching from the low-speed scan mode to the high-speed scan mode; The upstream station transmits a low-speed scan restart command that instructs to restart the low-speed scan in the transmission frame immediately before switching from the high-speed scan mode to the low-speed scan mode, including each of the 7 transmission frames, and the slave station receives the command. If a transmission permission token is included in the received signal of the transmission frame sent from the transmission frame, the own station transmission data corresponding to either the high-speed scan mode or the low-speed scan mode is transmitted without the transmission permission token. frame to the downstream station, and when the transmission frame is received by the own station after going around the loop, the transmission permission token is included in the transmission frame and transmitted to the downstream station, and the slow scan is interrupted in the received signal. When the command is included, even if the transmission permission token is obtained, transmission is temporarily interrupted and the transmission permission token is held; when the received signal includes the slow scan restart command, the transmission permission token is held. If the received signal contains a transmission permission token, the transmission frame transmitted from another station is resumed, and the data of the transmission frame is transferred to the high speed scan mode and the low speed scan mode. A loop-shaped data transmission method characterized in that the data transmission method is configured as a slave station that stores data in its own receiving memory corresponding to any one of the modes.