JPS6180926A - Loop type data transmission control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a loop-type data transmission control device connected to a loop-shaped transmission path of a loop-type data transmission system, and particularly relates to a loop-type data transmission control device connected to a loop-shaped transmission path of a loop-type data transmission system, and particularly to a loop-type data transmission control device that is suitable for broadcast communication, etc. This invention relates to a k-7' type data transmission control device.

[Background of the invention]

In conventional loop data transmission systems, the throughput of the loop transmission line is generally several tens to hundreds of times higher than the throughput of the data transmission control device itself. When transmitting and receiving messages generated at arbitrary timing between data transmission control devices connected to such a loop-shaped transmission line by means of circular communication, etc., the transmission capacity of the loop-shaped transmission line is If the message processing capacity within the data transmission control device is low, the message reception processing capacity within each data transmission control device may be exceeded, resulting in a shortage of reception buffers and loss of received messages.

This is a case where one or more data transmission control devices in the loop simultaneously generate transmission messages at a certain timing, and it is assumed that the reception buffer inside the data transmission control device will not be able to store enough of the messages. .

Conventionally, as a countermeasure for such problems, a method has been adopted to reduce the transmission performance within the data transmission control device so as not to exceed the reception capacity of each data transmission control device. Transmissions were performed at fixed intervals by appropriate means so that the transmission performance of each data transmission control device was equal to the reception performance of the data transmission control device divided by the number of data transmission control devices in the loop. However, in this conventional method, a fixed ink-pulse is taken for all data transmission control devices connected in the loop, regardless of whether the number of devices actually transmitting is small or large. There was a problem in that the smaller the number of devices performing transmission, the lower the loop transmission efficiency.

[Purpose of the invention]

An object of the present invention is to solve the above-mentioned problems of the prior art, and to enable a data transmission control device that transmits a message from an arbitrary data transmission control device of a loop type data transmission system to be transmitted to other data transmission devices. To provide a loop type data transmission control device that can improve transmission efficiency by automatically controlling to always satisfy the transmission performance within the loop even when transmitting without being aware of the number of control devices.

[Summary of the invention! ! ] In a loop data transmission system, the present invention provides an arrangement in which each data transmission control device detects a transmission path occupancy permission signal token sent from upstream of the transmission path, and then sends a transmission message from the data transmission control device. Aiming at VcM, which is the origin of the system, transmission path occupancy permission signal tokens are sent out at time intervals commensurate with the reception capability of each data transmission control device so that each data transmission control device can send outgoing messages at time intervals commensurate with the reception capability of the data transmission control device. (I'm trying to make you do that.)
Specifically, when a data transmission control device sends transmission data to another data transmission control device, the data of one or more devices upstream from the device (this number is determined in relation to the performance of the system) is transmitted. If a transmission control device recognizes that a transmission message is already being sent to the same partner data transmission control device, after sending the transmission message of the device, the subsequent data transmission control device will continue to transmit data to the same partner. In order to avoid sending a message to the control device for a certain period of time, the sending of a transmission path permission signal token from the device is delayed by a certain period of time (determined in relation to system performance). This is a loop data transmission control device.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

FIG. 1 is a general system configuration diagram of a loop data transmission system showing an embodiment of a loop data transmission control device according to the present invention. In Figure 1, 1 is a data transmission control device (ST*~
5Ts), 2 is a loop-shaped transmission path that connects the data transmission control device fil and transmits signals.

FIG. 2 is a frame configuration diagram of the HDLC format used for sending and receiving messages between the data transmission control devices 1 (8T1 to 8Ts) on the loop-shaped transmission path 2 of FIG. 1. In Fig. 2, F is a unique 8-bit code flag indicating the start and end of the frame, DA is the destination station address indicating the address of the data transmission control device 1 to which the data is to be sent, and C is the address for each control. The control command used is not particularly related to the present invention, and eight are the source station address indicating the address of the data transmission control device that sent the data, and DATA.
is the message information, Fe2 is 71 to check the frame for errors and if there is an error, -e is the error message information to be discarded, and -7 is.

FIG. 3 shows a loop type data transmission control device 1 (
FIG. 1 is a block configuration diagram showing an embodiment of FIG. 1). Third
In the figure, 3 is a receiver that demodulates and reproduces the received signal from the loop-shaped transmission path 2, 4 is a transmitter that modulates transmission data and sends it to the loop-shaped transmission path 2, 5 is an HDLC control circuit, and 6
7 is a microprocessor (MPU), and 7 is a memory (ROM) in which a microprogram for controlling the data transmission control device 1 by the microprocessor 7 is stored.
, 8 is a memory (
RAM), 9 is an input port (PPI), and 10 is a selector control circuit (CTL) forming a transmission data selection signal generation circuit.
), 11 is a multiplexer (MPX) that serves as a transmission data selection circuit, and 12 is a POL pattern generation circuit (POLGEN) that generates a transmission line occupancy permission signal token (POL) pattern that indicates the availability of a transmission line for special pattern tokens.
), 13 is an R8v pattern generation circuit (几5VGEN) that generates a transmission path occupancy display signal token (几SV) pattern indicating that the transmission path of the special pattern token is occupied.
, 14 is a pattern detector (PAT DET) that detects the POL/R8V pattern of the special pattern token;
15 is an interrupt signal to the microprocessor 6; 16 is a microcomputer bus connecting circuits related to the microprocessor 6;

First, to explain the general operation of this configuration, the received signal from the loop-shaped transmission line 2 is demodulated and regenerated through the receiver 3.
The signal is input to the HDLC control circuit 5 and configured as a received frame. When the surface is round, the pattern detector 14 detects a special pattern token POL/
The general Sv pattern is detected, and the detection signal is sent to the selection signal generation circuit (selector control circuit) 10 of the transmission data selection circuit (multiplexer) 11 and the microprocessor 6.
is input to the input port 9, which can be viewed as its status information. The frame format received data configured by the HDLC control circuit 5 is transmitted to the data transmission control device 1.
If the data is destined for the
, C7 frame end flag F (FIG. 2) is received, the microprocessor 6 is notified by turning on the interrupt signal 15. Further, the received data demodulated and reproduced by the receiver 3 is directly sent to the multiplexer 11, modulated by the transmitter 4, and sent to the transmission line 2.

If the data is not addressed to this data transmission control device,
The data is not stored in the reception buffer in the memory 8 and is discarded from the device.

FIG. 4 is a flowchart showing the general operation mechanism of data transmission of the present data transmission control device of FIG. According to Figure 4! To explain the general operation of data transmission in Figure 3, when the present data transmission control device 1 generates a request to transmit data to another data transmission control device and detects a POL pattern from the received data, it immediately sends it to the R8V.
After converting it into a pattern and indicating that the transmission line 2 is occupied, the transmission data is sent from the memory 8 via the HDLC control circuit 5 and the multiplexer 11 to the transmitter 4 (transmission line 2).
Send to. When this data transmission is completed, a POL pattern is selected and transmitted.

By repeating the above general operation, each data transmission control device on the loop can transmit and receive data evenly.

Next, FIG. 5 is a flowchart illustrating the operation mechanism of the method of delaying the sending of a POL pattern according to the present invention for data transmission of the data transmission control apparatus of FIG. 3.

To explain the operation of this method of data transmission in FIG. 3 with reference to FIG. 5, the HDLC control circuit 5 always monitors the destination station address DA (FIG. 2) in the received frame, destination station address DA (required number), that is, the data transmission control device 1 among the upstream data transmission control devices 1 that have already sent data.
The destination station address DA in the frame sent by the data transmission control device 1 (generally a predetermined number) closest to the destination is stored in the reception buffer of the memory 8. In this state, when the present data transmission control device 1 generates a request to transmit data to another data control device, whether or not dummy data is produced after the received frame of the latest destination station 73771770. Check out the
If this is detected, the dummy flag is turned on. For example, all of this dummy data is an l pattern, and since it does not form a frame, it is treated as meaningless data, and this dummy data flows when no meaningful data flows between frames. The HDLC1)tlJ control circuit 5 of the data transmission control device 1 is configured as follows. Next, when a POL pattern is detected from the received data, the POL pattern is immediately converted to R8 as described above.
V pattern and sends the transmission data.

After the data transmission is completed, the latest one (generally a predetermined number) previously stored destination station address DA is sent to the destination station address DA of the frame transmitted by the data transmission control device l, ! :Compare and the latest one (generally a predetermined number) matches 9, ka, 2. O 777 ka 1 off □ 7, tsu ga, i, After sending the specified byte of dummy data from the IHDLC control circuit 5, PO
Send L pattern.

If it is other than this, the KPOL pattern is immediately sent out as in FIG. 4.

Further, FIG. 6 is a time chart illustrating data transmission and reception according to the flowcharts of FIGS. 1 to 3, FIGS. 2 (generally more than one) trowels, that is, the maximum number of 2 of the upstream data transmission control device 1
Assuming that the data transmission control device 1 on the receiving side can process up to the sum of frames sent by (generally multiple) devices without overflowing the reception buffer, the data transmission control device 1 (ST2 to 5Ts) continuously Data transmission device 1
The case where data is sent to (STa)K is shown as an example. In FIG. 6, when the data transmission control device 1 (ST2) receives a POL pattern sent from the upstream data transmission control device 1 (sTt), the data transmission control device 1 (ST2) converts the POL pattern into a SV pattern and sends it to the data transmission control device. 1 (ST2) to the destination data transmission control device 1 (STs), and then sends out the KPOL pattern (FIG. 4). This data transmission side? N.J.
When the data transmission control device 1 (STs) receives the information sent from the device 1 (8Tz), it transmits the FLSV pattern and the data addressed to the data transmission control device 1 (STg) from the source data transmission control device 1 (ST) as is. Then, after converting the POL pattern to an R8V pattern and sending it, send the transmission data from the data transmission control device 1 (8Ts) to the destination data transmission control device 1 (STs), and then send dummy data for a certain time interval. Then, the POL pattern is sent out (Fig. 5, dummy flag is off). When the data transmission control device 1 (ST4) receives the information sent from the data transmission control device 1 (ST3), it sends out the R8V pattern and the transmission source. After sending the data and dummy data addressed to the data transmission control device 1 (STs) from the data transmission control device 1 (ST2. Device 1 (S
T4 ) to destination data transmission control device 1 (STg
), the POL pattern is immediately sent out (FIG. 5, dummy flag is on). When the data transmission control bag fifl (STs) receives the information sent from the data transmission control device f (ST4), it receives the SV pattern and the source data transmission control device 1 (
STz~5T4) and dummy data are sent as they are, and then the POL pattern is converted to a FLSV pattern and after sending, the data transmission control device 1 (STs) sends the transmission data to the destination data transmission control device fill (8T6). After that, dummy data is sent out for a fixed time interval, and then a POL pattern is sent out (FIG. 5, dummy flag is off). This data transmission control device 1 (s'rs
) receives the information sent from the data transmission control device 1 (
s'rs), the source data transmission control device 1
(ST2゜STs) and the same device 1 (8T4, 3T
Continuous data from 2 (generally multiple) device valves from s ) are received at regular time intervals of 0'''°8-7''-' at intervals of ''(1'') and '-1 is stored in the reception buffer in memory 8. Store.

In the explanation of the operation shown in FIGS. 5 and 6 above, when the reception capacity of the data transmission IF control device 1 is for two consecutive devices, that is, the receiving side overflows the reception buffer to the sum of the frames sent by the two devices at most. However, in general, if the receiving capacity is for two or more consecutive devices, the receiving side will overflow the receive buffer to the sum of the V-m sent by at most two or more devices. If it is assumed that processing can be performed without the need for dummy data, the position at which dummy data is inserted or the length of dummy data will change accordingly.

Next, an example of the transmission efficiency of the data transmission control device of the present invention will be explained in comparison with a conventional device. Now loop transmission line 2
The number of data transmission control devices 1 connected to 10 and 1
The reception performance of the data transmission control device 1 is 20 KBytes.
Assume that the number of data transmission side #devices 1 actually executing transmission to one specific data transmission control device 1 is six. In this case, in the conventional method where the transmission performance of the data transmission control device is the performance obtained by dividing the reception performance of the data transmission control device by the number of data transmission control devices in the loop, the transmission performance of the data transmission control device (fixed performance (including target interval) is 20 KByte/S
/ 10 = 2 KByte/s, specific 1
When there are 6 devices transmitting data to 1 device, the transmission efficiency is 2 KByte/s x 6 = 12
It becomes KBYte/S. In contrast, after the two data transmission control bags +11 of the present invention transmit continuously, there is an interval (for example, an interval of 20 KByte/s) (by delaying the POL pattern transmission), and then the next two
In the method in which one data transmission control device 1 transmits continuously, the transmission efficiency is IQ[Byte/s x 6-20
K] 3yte/s X 2= 20KByte/S
This is an improvement of 1.6 times compared to the conventional device. Note that when the number of devices is even larger, the improvement in transmission efficiency by the device of the present invention becomes even more remarkable.

As described above, according to this embodiment, when data for broadcast communication is sent at any timing from a data transmission control device connected to a loop transmission path, or when multiple data transmission control devices are connected to the same data transmission control device. When continuously transmitting data from the source, the data transmission control device on the sending side automatically sets P so that each data transmission control device can perform optimal reception processing.
Since the transmission timing of the OL pattern is delayed, the transmission efficiency of the transmission system can be greatly improved.

〔Effect of the invention〕

As described above, according to the loop-type data transmission control device of the present invention, when performing circular communication on a loop-shaped transmission path, the data transmission control device automatically adjusts the time interval between data transmissions at the time of one transmission. This has the effect of significantly improving the performance of loop-shaped transmission lines compared to conventional devices.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram showing an embodiment of a loop-type data transmission control device according to the present invention, and FIG. 2 is an HDL diagram of FIG. 1.
C format frame configuration diagram, g3 is a block configuration diagram showing an embodiment of the loop type data transmission control device according to the present invention,
FIG. 4 is a flowchart of the general operation of FIG. 3, FIG. 5 is a flowchart of the same operation of delaying the POL pattern according to the present invention, and FIG. 6 is a time chart. l...Data transmission control device, 2...Loop transmission line,
3...Receiver, 4...Transmitter, 5...HD L
CIJ control circuit, 6... microprocessor (MPU)
, 7...Memory (ROM), 7...Memory (RAM)
, 10... selector control circuit (selection signal generation circuit),
11...Multiple Vx (transmission data selection circuit), 1
2...POL pattern generation circuit, 13...几Sv pattern generation circuit, 14...POL/R8V pattern detector.

Claims (1)

[Claims] 1. In a loop data transmission system comprising a loop-shaped transmission path and a plurality of data transmission control devices connected to the transmission path, the data transmission control device performs transmission at the time of a transmission request. means for transmitting a transmission path occupancy indication signal token upon receiving a transmission path occupancy permission signal token from on-stream; means for transmitting transmission data from the data transmission control device after transmitting the transmission path occupancy indication signal token; means for detecting the destination data transmission control device address of the transmission data that the data transmission control device has already sent out, and means for detecting the same address from the detected at least one or more predetermined number of upstream data transmission control devices and the data transmission. If the address of the destination data transmission control device to which the control device sends the transmission data matches, after sending out the transmission data, it sends out dummy data at a predetermined time interval, and then sends out a transmission path occupancy permission signal token, and they must match. For example, a loop type data transmission control device comprising means for immediately sending out a transmission path occupancy permission signal token after sending out the transmission data. 2. In a loop data transmission system consisting of a loop-shaped transmission path and a plurality of data transmission control devices connected to the transmission path, the data transmission control device controls the transmission path from upstream of the transmission path at the time of a transmission request. means for transmitting a transmission path occupancy indication signal token upon receiving the occupancy permission signal token; means for transmitting transmission data from the data transmission control device after transmitting the transmission path occupancy indication signal token; and an upstream data transmission control device. means for detecting the destination data transmission control device address of the transmission data that has already been sent and whether or not dummy data is being sent after the transmission data; and a predetermined number of at least one detected upstream data transmission control device. If the same address from the data transmission control device matches the destination data transmission control device address sent by the data transmission control device, and dummy data is not sent, dummy data is sent at a predetermined time interval after the transmission data is sent, and then the data is transmitted. A loop type data transmission control device comprising means for transmitting a path occupancy permission signal token and, in other cases, immediately transmitting a transmission path occupancy permission signal token after sending the transmission data.