JPS58201440A - Loop mode transmission system - Google Patents

Abstract

PURPOSE:To stop the transmission and to perform the transmission efficiently, by transmitting a data from a station equipment obtaining the right of transmission, and receiving the transmission data of itself returned cyelically from a loop at the sme time, in a loop mode transmission system. CONSTITUTION:When a station device 1 obtains the right of transmission, a tranmission control section 19 activates a line RS, a transmission signal changeover device 16 of a repeater 7 is selected to the position (b), and after an insignificant signal is transmitted for a prescribed time T1, a data is transmitted through a line SD, and then, the insignificant signal is transmitted for a prescribed time T2. Even when a receiving control section 18 is possible for receiving in this case, if the data returns cyclically in the transmission line with a delay time TL, the line RS is disconnected by receiving it, the transmission signal changeover device 16 is selected to the position (a) to attain a relay mode. No adjustment is required even for a comparatively small-sized transmission system through this and a good transmission efficiency is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a data transmission completion operation technique when transmitting data from a station device to a transmission path in a loop transmission system in which several station devices are connected to a loop transmission path. As a conventional loop-shaped transmission system for this food, the one shown in FIG. 1 is known. FIG. 1 is a block diagram showing a conventional loop transmission system. In Figure 1, /, 2, J, ...... 6 is the station equipment, 7, J, 9, ...... / is the repeater corresponding to each station equipment 1 or 2, and LS is the repeater corresponding to each station equipment 1 or 2. It is a loop-shaped transmission line. FIG. 2 is a block diagram showing the internal structure of the station equipment and repeater in FIG. 1. In figure 1,
/3 is a loop-shaped transmission path, ZIN is a receiver, IS is a transmitter,
/l is a transmission signal switch, and l7 is a half-duplex transmission control unit. Further, FIG. 3 is an operation timing characteristic diagram of each part of the Glock block diagram shown in FIG. 2.

Next, the operation of the conventional loop transmission system will be explained using FIGS. 1 to 3 above.

In the loop transmission system shown in FIG. 1, it is assumed that the transmitters of each station device L to B are moved by a baton bus method. Now, for example, station equipment l is transmitting +
If r1 is acquired, the line R87ON shown in Figure 2
Then, the transmission signal switch 1tQb side of the repeater 7 is switched, and an unexpected signal (for example, all "
/” or all “O” signals), the line S
Data is transmitted through D. After completing this data transmission, an unexpected signal is transmitted for a certain period of time T2, and then the line R
8Q OFF and transmit signal switch/A Q a 1il
Switch to relay mode. When the line R6 is immediately turned off after the data transmission is completed, the data returns through the looped transmission line /3 and returns through the line RDQ with a loop delay time TL, as shown in Figure 3. The rear part of the signal is transmitted onto the loop-shaped transmission path 13 again. In order to prevent this, it is necessary to set the above-mentioned fixed time T2 f loop delay time TL or more for transmitting an unexpected signal.

Since the conventional loop transmission system is configured as described above, the loop delay time TL of the data that goes around the loop transmission path 13f and returns is determined by the scale of the loop transmission system, that is, the number of repeaters. and can be determined by the transmission path. However, the above-mentioned certain times Ti, T
2, determine each value assuming the largest scale, or
Alternatively, each value must be adjusted for each transmission system. In the former case, the efficiency becomes extremely poor in a small-scale transmission system, and in the latter case, there are drawbacks such as an increase in test adjustment time and a decrease in maintainability. This was done to eliminate the drawbacks of the conventional ones, and the station equipment that has acquired the transmission right transmits its own data, and at the same time receives its own data that goes around the loop-shaped transmission path and returns. However, it has a configuration that stops sending data on the transmission path when all of its own data has been received, and even in the case of a relatively small-scale transmission system, data transmission efficiency is high. DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, which also aims to provide a loose transmission system without adjustment elements.

Fig. 3 is a block diagram showing the internal structure of the station equipment and repeater of a loop transmission system according to an embodiment of the present invention, and Fig. 3 is an operation timing characteristic diagram of each part of the block diagram shown in Fig. 7. It is. In Fig. ψ, l is the station equipment, 7 is the repeater, /3 is the loop-shaped transmission path, /g is the receiver, /j
is a transmitter, /6 is a transmission signal switcher, /l is a reception control unit,
/9 is a transmission control section O Next, the operation of the loop transmission system which is an embodiment of the present invention will be explained with reference to FIGS. Now, for example, if the station device l shown in FIG. 7 acquires the transmission right, the line R8 is turned on and the transmission signal switch 16 of the repeater 7 is switched to the side b, and for a certain period of time shown in FIG. T1
After transmitting an unexpected signal for a certain period of time, data is transmitted through the line SD, and after completing this data transmission, a certain period of time T2
At this time, when an unexpected signal is transmitted, the reception control unit l♂ is in a state capable of receiving data. Therefore, as shown in FIG. 5, the loop delay time 'rLa is delayed and the loop-shaped transmission line 73? - When the data returns through the line RD, the reception control section 7g starts receiving the data. When the reception control unit/l detects that all the transmitted data has returned after completing one cycle on the transmission line 13, the line R8I
? ! :0FFl, the signal is switched to the transmission signal switch 161a side to set the relay mode. In this way, the reception control unit
When g is detected, the line R8 is turned off and the transmission of data onto the transmission line /3 is stopped, thereby making it possible to prevent deterioration of the transmission efficiency of data transmission.

As described above, according to the loop-shaped transmission system according to the present invention, the station device that has acquired the transmission right transmits its own data, and at the same time receives its own data that has returned after going around the loop-shaped transmission path. Since the configuration is such that the transmission of data onto the transmission path is stopped when all of the own data has been received, adjustments depending on the scale of the transmission system are not required, and the system is relatively small. Even in the case of a large-scale transmission system, the excellent effect of efficiently transmitting data can be achieved.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional loop transmission system, Fig. 2 is a block diagram showing the internal structure of the station equipment and repeater in Fig. 1, and Fig. 3 is a block diagram showing the structure in Fig. 2. FIG. 1 is a block configuration diagram showing the internal configuration of the station equipment and repeater of a loop transmission system which is an embodiment of the present invention, and FIG. 5 is a block configuration diagram of each part shown in FIG. O 7 to 6...station equipment, 7 to 12...repeater,
13...Loop-shaped transmission line, /4...Receiver, /3
...Transmitter, /6...Transmission signal switch, /7...
Half-duplex transmission control unit, /l...Reception control unit, /9...
Transmission control unit. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Shin Tameno - Figure 1 Figure 2 Figure 7, Figure 3 Figure 4, 7 Figure 5

Claims (1)

[Claims] In a loop-shaped transmission system in which a plurality of station devices are connected to a loop-shaped transmission path, the station device is provided with means for transmitting data to the transmission path and means for receiving data, and transmits data on the transmission path while transmitting its own data. Is there an unexpected signal even after receiving the own data that has gone around and completed sending the own data? 5. Performs a relay operation in which the transmitter continues to transmit data, and when all the transmitted data is received by the previous station receiving means, the transmitter stops transmitting the data on the transmission path and transmits the received data as is. What is claimed is: 1. A loop-shaped transmission system characterized by having a configuration comprising: