JPS6262646A - Loop system data transmission system for both optical and electric transmission lines - Google Patents

Abstract

PURPOSE:To constitute economically the titled system by including a station connected to any of an electric transmission line and an optical fiber transmission line so that the signal transmission lines of both electric and optical fiber types exist together. CONSTITUTION:A main station 40 and a terminal station 41 are coupled in a loop by an optical fiber TL1 and an electric cable TL2. In preparing a transmission interface circuit for both electric and optical fiber types to each station, any system is used freely depending on the requirement of the joint work. Further, depending on the application, most of stations use the electric lines from the economical point of view or the optical fiber is used according to the noise environment. No practical hindrance exists in preparing a few stations utilizing both the electric lines and the optical fibers.

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention connects a main station (also referred to as a center device) that controls transmission and a plurality of terminal stations (also referred to as terminals) via a common loop-shaped transmission path, and allows these stations to communicate with and from outside the system.
In a system that mutually transmits output data or internal data, an electrical transmission line made of twisted pair electric wires, etc. and an optical fiber type transmission line made of optical fiber are mixed in one transmission line. Regarding the system that makes it possible.

[Prior art and its problems]

Various methods are used to configure transmission paths in transmission systems. For example, as shown in Figure 3, multiple stations (
When a transmission path is configured to connect a main station and a plurality of terminal stations in a loop, the following problems occur. In other words, there are two types of transmission line constituent materials: electric ones using conductor wires (electric wires) such as twisted pair cables and coaxial cables (hereinafter collectively referred to as electric wire cables or simply cables), and optical fibers. However, there are advantages and disadvantages between the two, and the use cannot be limited to only one type. The reason for this is that: ■Electric systems have low cable costs and are easy to install and purchase materials, but there are restrictions on transmission speed, and because cables are used to connect transmission devices at two different locations, It has the disadvantage of being susceptible to noise due to interference between transmission devices. - Optical fiber type has a high transmission speed, and the transmission devices are electrically insulated from each other by optical fibers, making it possible to improve the noise resistance of the device. However, on the other hand, optical fibers are generally expensive, and the connection work is not only difficult to perform unless you are a professional engineer, but also requires the use of adhesive in many cases, which requires a long time to connect. There is a problem. On the other hand, when considering the environmental conditions in which transmission lines are placed, for example, in plants, signal lines (transmission lines) may be laid indoors or outdoors, and equipment ducts dedicated to signal transmission lines may be used. There are cases where it is necessary to install the power cable in parallel with the power cable. Considering the above case, there is a problem in that outdoor signal lines are susceptible to lightning strikes. In addition, if a signal transmission line is installed in parallel with a power cable, loads such as motors and transformers may be struck on the power line side, or lightning strikes may occur on the power line side.
When various abnormal voltages enter the signal transmission line side due to coupling between the power line and the signal transmission line, signal transmission is disturbed or malfunctions due to noise are likely to occur. In order to ensure reliability, it is sometimes more advantageous to use optical fibers as signal transmission lines in such environments than to install dedicated ducts for signal (electrical) lines. In this way, even in one transmission line, there is a demand to freely combine both electric type and optical fiber type. Generally, optical fiber systems are expensive, and it is difficult to use optical fibers for everything, so it is important to limit the application to only the necessary areas while increasing the reliability of transmission while also minimizing the cost increase of the entire transmission system. The big question is how to suppress it.

[Purpose of the invention]

The present invention eliminates the above-mentioned problems and provides a data transmission system in which a main station that controls transmission and a plurality of terminal stations are connected via a common transmission line in the form of a loop. Provides a data transmission system that includes a station that can be connected to either of the transmission lines, allows both electrical and optical fiber signal transmission lines to coexist, and allows the system to be configured economically. The purpose is to

[Key points of the invention]

The main point of the present invention is to connect a main station that controls transmission and a plurality of terminal stations via a common loop-shaped transmission path, and to exchange data between the main station and the terminal stations or between the terminal stations. In the data transmission system, the loop-shaped transmission line includes at least an electric transmission line (such as an electric wire cable) for transmitting or receiving, which uses electricity as a signal transmission medium, and at least an electric transmission line (such as an electric wire cable), which uses electricity as a signal transmission medium. (also referred to as an optical fiber transmission line (optical fiber, etc.) for transmission or reception,
Further, the main station or terminal station has a transmitting means (such as a transmitting buffer, a photocoupler, etc., hereinafter referred to as electric transmitting means) coupled to the transmitting electric transmission line, Receiving means (receiving buffer, photocoupler, etc., hereinafter referred to as electrical receiving means) is coupled to the receiving electrical transmission line, and transmitting means (E10 converter, etc., hereinafter referred to as optical receiving means) is coupled to the transmitting optical fiber transmission line. Among the four means, a.
) with all four means; or b) with electrical transmitting means and receiving means; or C) with optical fiber transmitting means and receiving means; or d) with electrical transmitting means. and e) an optical fiber type receiving means, or e) an optical fiber type transmitting means and an electric receiving means. At the same time, the main station that controls transmission and multiple terminal stations are connected via a common loop-shaped transmission path, and data is exchanged between the main station and the terminal stations or between the terminal stations. In the transmission system, at least some of the main stations or the terminal stations include transmitting means and receiving means to be coupled to respective transmitting and receiving transmission paths using electricity as a signal transmission medium; The present invention is characterized in that it is provided with transmitting means and receiving means to be coupled to respective transmission lines for transmitting and receiving using light as a signal transmission medium.

[Embodiments of the invention]

The present invention will be described in detail below based on FIGS. 1 to 3. FIG. 1 is a block circuit diagram showing the configuration of an external communication ink face unit as an embodiment of the present invention, and FIG. 2 is a block circuit diagram showing the configuration of a transmission control unit in each station.
Similarly, FIG. 3 is a block diagram showing the overall configuration of the loop data transmission system. In each figure, the same reference numerals indicate the same or corresponding parts. Also, signal levels "old gh" and "Low" are simply written as H and L. In FIG. 3, 40 is a main station (center device) that controls transmission, 41 (41-1, 41-2...)
is multiple terminal stations (terminals), TL is the main station 40 and the terminal station 41
Transmission lines TLI and TL2 that couple the two in a loop are an optical fiber (optical fiber transmission line) and an electric cable (electrical transmission line), respectively, which constitute the transmission line TL. FIG. 2 shows the configuration of the transmission control section 24 in the main station or terminal station in FIG. 3. In the figure, 1 is a reception terminal, 2 is a transmission terminal, 3.4 is a level converter, 5 is a reception signal line, 6 is a start bit detector, 7 is a synchronization clock generator, 8 is a sampling circuit, 9.10 is an AND circuit, 11 is an OR circuit, 12 is an inverter circuit, 13
14 is a start bit detection signal line, 15 is a synchronized clock signal line, 16 is a reception bypass signal line, 17 is a transmission signal line, 18 is a transmission/reception switching signal line, 19 is a microcomputer (hereinafter referred to as a microcomputer) 21 is an output level conversion circuit. 22 is an output terminal, and 23 is a setting key matrix. Here, the means 21 to 23 may have completely different forms depending on the functions possessed by the transmission device, and FIG. 2 mainly shows the case of a receiving terminal station as a representative. The operation of the transmission control section configured as shown in FIG. 2 is as follows. The level converter 3 converts a received signal, which will be described later, into a signal at a signal voltage level (for example, TTL level) within the transmission control circuit. When the start bit is detected by the start bit detector 6, the converted received signal is sent to the synchronous clock generator 7.
Start. The sampling circuit 8 samples the voltage level of the reception signal line 5 at the rising edge of the synchronous clock waveform from the synchronous clock generator 7 and outputs a signal of the same level (for example, TTL level) to the reception bypass signal line 16. The transmission data selection circuit 13 transmits the signal on the bypass signal line 16 during reception, and the signal on the transmission signal line 17 during transmission, to the level converter 4 according to the contents of the transmission/reception switching signal line 18. The level converter 4 converts the voltage level used within the device (TTL level) again into a signal external to this device and transmits it to the next device. The microcomputer 19 has a function to perform serial transmission,
When receiving a serial signal, connect the transmit/receive switching signal line 18 to I.
Serial data can be read by setting the level f HIf and sampling the level of the received signal line 5 at the rising edge of the synchronous clock of the synchronous clock signal line 15 generated by the start bit of the received data. Further, when transmitting a serial signal, the transmission/reception switching signal line 18 is set to "L" level, and serial transmission data can be output from the transmission signal line 17. In this way, the received signal converted by the level converter 3 passes through the sampling circuit 8 and bypasses the present device.
It can then be retransmitted onto the transmission line by the level converter 4 again. Through such operations, the microcomputer 19 can receive data from an external device, and can also transmit proprietary data within its own device as needed. This transmission line TL uses a start-stop synchronization type signal, and in order to synchronize the devices, the first signal of one transmission character has a start bit, and this start bit allows synchronization. However, since this is a well-known technique, detailed explanation thereof will be omitted. FIG. 1 shows the configuration of the external communication ink face section within the station. In the same figure, TLIR and TLIS are respectively the receiving optical fiber and the transmitting optical fiber that constitute (or can constitute) the optical fiber TL1 in the transmission line TL, and TL2R and TL2S are the electric wire cables in the transmission line TL, respectively. These are a receiving electric wire cable and a transmitting electric wire cable that constitute (or can constitute) TL2. In this example, as shown by the solid line, the reception cable TL2 is used for reception.
It is assumed that R is used for transmission, and that a transmission optical fiber TLIS is used for transmission. 24 is the transmission control unit explained in FIG. 2, 1 is its receiving terminal, 2 is also its transmission terminal, and this external communication ink face part constitutes an ink face circuit between the transmission path TL and the transmission control unit 24. are doing. Reference numeral 5 (SL, S2) is a changeover switch that selects which of the ink face circuits for the electric transmission line and the ink face circuit for the optical fiber type transmission line is used. However, depending on the circuit configuration, the switches SL and S2 may be omitted and the lines to be connected by the switches may be connected using conductive wires. 28 is the signal level H on the receiving wire cable TLZR side
/L, 29 is a photocoupler for insulation from external signal circuits, 30 is a transmission control unit 24
This shows a buffer for matching the signal level with the Similarly, 32 is a transmission buffer for ensuring the signal level on the transmission wire cable TLZS side, 33 is an insulating photocoupler, and 34 is a buffer for adjusting the signal level. 35 is a digital link for optical fiber signal transmission, and a commercially available product can be used as is. The digital link 35 is composed of an optical/electrical (0/E) converter circuit 38 coupled to the receiving optical fiber TLIR and an electrical/optical (E/○) converter circuit 39 coupled to the transmitting optical fiber TLIS. . Figure 1 shows that for reception, electrical transmission is used via the reception cable TL2R, and for transmission, optical fiber transmission is used via the transmission optical fiber TLIS. There is. For this reason, the transmission electric cable TL2S and the reception optical fiber TLIR are not used, and are therefore indicated by broken lines. With this configuration, signals can be transmitted both by optical fiber type and electric type. In the data transmission system shown in FIG. 3, the main station 40 and the terminal station 4
1 is coupled in a loop with an optical fiber TLI and an electric wire cable TL2. In the figure, the transmission line TL of the optical fiber TL1 section is shown as a double line, and the electric wire cable TLZ section is shown as a single line. In this way, by preparing both optical fiber and electrical transmission interface circuits at each station as shown in Figure 1, you can freely use either method depending on the level of connection work required. It is possible. However, it may be economically wasteful to prepare a transmission ink face circuit as shown in FIG. 1 in every station. As you can see in Figure 3, if you prepare the types of stations shown in the table below, or prepare an external transmission ink face unit that can be converted into stations shown in the table below. , the system can be constructed economically by using the necessary units. All you need to do is prepare five types of stations with the functional parts marked O in the table above. Also, if there are no financial problems, please use the above table! lh
It is sufficient to prepare only 1 types of stations and select the necessary wiring system. Also, depending on the application, from an economic point of view, most stations may be of the electrical type (N112 shown in the table above), or from the standpoint of noise environment, most of the stations may be of the optical fiber type (3). In this case, for example, if you prepare a small number of N11L1 stations in the above table that can use both electrical and optical fiber types, there will be no practical problem, so it is not necessary to cover all of the stations 1 to 5 in the above table. There is no need to prepare stations of this type.

【Effect of the invention】

As is clear from the above description, according to the present invention, a station that can use both an electric type and an optical fiber type transmission line in a transmission line connecting a main station and a terminal station in a loop, or an electric type Prepare a station that uses either an optical fiber type transmission line, or a station where one of the transmitting and receiving function parts is for an electrical transmission line and the other is for an optical fiber type transmission line. At the very least, both electric and optical fiber partial transmission lines (this partial transmission line shall include only one transmission or reception partial transmission line) should be installed in one loop transmission line. For outdoor transmission lines, locations with poor noise environments, or applications where signal lines must be routed in parallel with other power cables, optical fiber transmission lines should be used to reduce the noise environment. In relatively good locations, we decided to use electric transmission lines, which are cheap to construct and easy to handle, making the entire data transmission system economical, and the construction period short, without compromising reliability. It can be realized without any problem.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a block circuit diagram showing the configuration of an external communication ink face section in the station as an embodiment of the present invention, and FIG. 2 is a block circuit diagram showing the configuration of the transmission control section in the station. circuit diagram,
FIG. 3 is a block diagram showing the overall configuration of the same loop data transmission system. 40: Main station (center device), 4N411.41-2-
-------->: Terminal station (terminal), TL: Transmission line,
TLI: Optical fiber, TLIR: Receiving optical fiber, T
LIS: Optical fiber for transmission, TL2: Electric wire cable, T
L2R: Receiving electric wire cable, TL2S: Transmitting electric wire cable, 24: Transmission control section, 25: External communication ink face section. ? 4: Yi Yun Sending System - Figure A, Figure 2, Figure 3

Claims (1)

[Claims] 1) A main station that controls transmission and a plurality of terminal stations are coupled via a common loop-shaped transmission path, and data is exchanged between the main station and the terminal stations or between the terminal stations. In the data transmission system, the loop-shaped transmission line includes at least an electrical transmission line for transmitting or receiving, which uses electricity as a signal transmission medium, and at least an electric transmission line, which uses light as a signal transmission medium, for at least transmission. or an optical fiber transmission line for reception.
A loop-type data transmission system that can be used for both electrical purposes. 2) In the data transmission system according to claim 1, the main station or the terminal station includes a transmitting means (hereinafter referred to as electrical transmitting means) coupled to the transmitting electrical transmission line, and a transmitting means coupled to the transmitting electrical transmission line, receiving means (
(hereinafter referred to as an electrical receiving means), a transmitting means (hereinafter referred to as an optical fiber transmitting means) coupled to the transmitting optical fiber transmission line, and a receiving means (hereinafter referred to as an optical fiber transmitting means) coupled to the receiving optical fiber transmission line. 4)
a) all four means, or b) electrical transmitting means and receiving means, or c) optical fiber transmitting means and receiving means, or A dual-optical/electrical loop type, characterized in that it is either d) equipped with an electrical transmitting means and an optical fiber receiving means, or e) equipped with an optical fiber transmitting means and an electrical receiving means. data transmission system. 3) Data transmission in which a main station that controls transmission and multiple terminal stations are connected via a common loop-shaped transmission path, and data is exchanged between the main station and the terminal stations or between the terminal stations. In the system, at least some of the main stations or terminal stations include transmitting means and receiving means to be coupled to respective transmission lines for transmitting and receiving using electricity as a signal transmission medium, and transmitting means and receiving means for transmitting and receiving signals using electricity as a signal transmission medium. What is claimed is: 1. A loop-type data transmission system for both optical and electrical use, comprising a transmitting means and a receiving means to be coupled to respective transmission lines for transmitting and receiving as signal transmission media.