JPS6189733A - Optical transmission communication system - Google Patents

Abstract

PURPOSE:To attain freely the communication with the same protocol as a con ventional one by relaying and amplifying an optical signal of the 1st and 2nd optical transmission lines transmitting an optical signal in opposite direction mutually at each communication equipment inserted at the midpoint and synthe sizing the two-way signals as a reception signal and transmitting the transmis sion signal in two-way at the same time. CONSTITUTION:Transmission lines 1, 2 such as optical fibers transmitting an optical signal in opposite directions are provided as transmission buses. A master set 4 as a communication equipment and plural terminal devices 51-54 are inserted to each midpoint of them via interfaces (I/F)31-35, an optical signal from reception sides 1a, 2a is converted individually into an electric signal by photoelectric converters (O/E)14a, 14b, syntherized by an OR gate 18c and given to a device 17 as a reception signal. Then the optical signal from any directionis received by the device 17, the transmission signal from the device 17 is branched at an outputof a BF16b, given to electrooptic converters (E/O)15a, 15b and converted individually into an optical signal, which is transmitted in two ways.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an optical transmission communication system suitable for a communication system comprising a plurality of communication devices that communicate with each other via a common transmission bus. be.

[Conventional technology]

The method of connecting multiple communication devices to a common transmission bus and communicating between each device is used in air conditioning control equipment, building management systems, etc. It is used for data transmission between sensors or controlled devices, but when updating the transmission bus line using an electric line to an optical transmission line, or because the installation conditions are susceptible to electrical interference, it is necessary to use it from the beginning. When using an optical transmission line as a transmission bus, it is possible to adapt communication from electrical signals to optical signal communication without making any particular changes to the transmission procedures (hereinafter referred to as protocols) assigned to each conventional communication device. requested.

[Problem that the invention seeks to solve]

However, if you simply insert an electro-optic converter and a photo-electric converter between a conventional communication device and an optical transmission line to combine them into a single optical transmission line, you will need to insert an optical coupler or optical splitter. Since this is inserted into the optical transmission path for each communication device, these optical losses accumulate, increasing the transmission loss of the optical signal, and reducing the signal-to-noise level of the receiving signal 4. This may cause the ratio to deteriorate.

The present invention has the purpose of fundamentally solving the conventional demands and problems, and provides an extremely effective optical transmission method that can use an optical transmission line as a transmission bus without changing the conventional protocol. It provides a communication method.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention is constituted by the following means.

That is, first and second optical transmission lines are provided as transmission buses that transmit optical signals in opposite directions, each communication device is interposed between these optical transmission lines, and each optical transmission line is The signals received from the receiving side are combined into a receiving signal 4, and the transmitting signal 4 is branched and transmitted to the transmitting side of each optical transmission line, and each signal received from the receiving side of each optical transmission line is individually combined. It is assumed that the signal is amplified and combined with the transmission number 4 and transmitted to the corresponding transmission side of each optical transmission line.

[For production]

Therefore, the optical signal on each optical transmission line (hereinafter referred to as transmission line) is
It is relayed and amplified by each communication device interposed in the middle, and
Signals from both directions are combined to form reception number 4, and
Since the transmission number 4 is simultaneously transmitted in both directions, and bidirectional transmission is essentially performed through the transmission path, communication can be performed using the same protocol as in the past.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to figures showing examples.

Figure 2 is a block diagram showing the entire configuration. As shown by the arrows, transmission lines 1 and 2 such as optical fibers that transmit optical signals in opposite directions are provided as transmission buses. At each intermediate point, there is an interface (hereinafter referred to as I/F)
A main device 4 and a plurality of terminal devices 5□ to 5.3 serve as communication devices via terminals 3□ to 35. is interposed, and each I/F 3□
Each receiving side of the first and second transmission lines 1.2 is connected to each receiving power R0°R2 of ~35, and the signals from these are combined inside I/'F'・3□~36. In addition, the reception output R is sent to each device 4゜51-54.
On the other hand, each device 4, 5□ to 5. Sent No. 4 from.

I'll'・3□～3. Given to the sending human power S, this\
The signal is branched at , and then transmitted from the transmission output S to the transmission side of each transmission path 1 and 2.

Note that, for example, a central control device or the like may be used as the main device 4.
At the same time, the terminal devices 5□-5. In this example, various sensors such as temperature, moisture pressure, flow rate, and fire control sensors with transmitting and receiving functions, or control target devices such as control valves, dampers, and air conditioning equipment are used. Data signals are transmitted and received between the devices 4, 51 to 54 under control according to a predetermined protocol, and the equipment to be controlled is controlled according to the detection power of each sensor.

FIG. 1 is a block diagram of the I/IF 3, and the receiving sides 1a, 2a and the transmitting sides 1'b, 2b of each transmission path are as follows:
Optical switches (hereinafter referred to as 08
) 13, the receiving sides 1a and 2a each have a photoelectric converter (hereinafter referred to as "photoelectric converter").

Q'') 14a, 14b and the transmitting side 1b.

Similarly, 2b is an electro-optical converter (hereinafter referred to as VO) 15a, 15b
The output of 0.14a is connected to the communication device (hereinafter referred to as device) via a buffer circuit (hereinafter referred to as BF) 16a.
It is sent to the OR gate 18a along with the transmission signal 4 from BF 17 via the BF 16b, and is combined there.
Driver' (hereinafter referred to as DR) 19a then 15a
On the other hand, the output of L o/F,・14b is B
Via F.16e, it is given to OR gate 18b along with the branched transmission signal 4 from the output side of BF.16b.
It was synthesized in
5b.

Further, the respective outputs of OIB 1'4a and 14b are combined by an OR gate 18e and sent to the device 17 as reception number 4.

In this case, the optical signals from the receiving sides 1a and 2a are
They are individually converted into electric signals by 14a' and 14b, combined by OR gate 18e, and then given to the device 17 as a receiving signal 4. Optical signals from any direction can be received by the device 17, and , the transmission signals from the device 17 are branched at the output of the BF 16b, given to the Elo 15a and 15b, each converted into an optical signal, and then transmitted in both directions. It becomes possible to freely transmit and receive data to and from all other devices connected as shown in Figure 2, and data signals can be transmitted and received using exactly the same protocol as when using a transmission bus line using an electric line.

On the other hand, each output of each 01E, 14a, 14b is BF-
16a.

16c, OR gates 18a, 18b and DR19a,
19b to the corresponding VO, 15a and 15b, and amplification and waveform shaping are performed in each BF and DR, so the optical signals from the receiving sides 1a and 2a suffer from waveform distortion and level reduction. However, after these are corrected, they are relayed as regular waveforms and levels and then transmitted to the transmitting sides 1b and 2b.

However, the I/F 3 receives, for example, a commercial power supply AC, converts it into a desired local power supply V in the power supply section 21, and supplies it to each section, but the power supply monitoring circuit 22 monitors the voltage of this. If the voltage drops below a predetermined voltage, O8.13
In order to restore the system, each switching unit directly connects the receiving sides 1a, 2a and the transmitting sides 1b, 2b of each transmission line 1, 2, and does not interfere with communication between other devices. .

Therefore, the same device 17 as the conventional one is used, and
By simply adding the F.3 function, it becomes possible to perform bidirectional communication using the transmission lines 1 and 2 using the same protocol as before with a good signal-to-noise ratio.

In addition, due to the relay operation with waveform shaping and level correction functions, there is no problem even if the optical transmission loss of transmission lines 1 and 2 increases, and there is no problem with communication between other devices even in the event of a power supply failure. becomes.

If you install a backup power source, O8-13
may be omitted, BF・16a-16e, DR-1
9a to 19e may be omitted depending on the situation, and the equivalent functions may be replaced with 0/
'E ・14a, 14b, E”0 ・15a+15b
The same is true even if it is provided inside the device 17. Mixing circuits, addition circuits, etc. may be used instead of the OR games 18a to 18e, and depending on the case, I/F 3 may be accommodated inside the device 17. ,
Various modifications are possible.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, by adding simple functions, it is possible to freely transmit optical signals in both directions using conventional equipment, and there is no need to change the conventional protocol. , remarkable effects can be obtained in communication systems that use a common transmission path.

[Brief explanation of the drawing]

The figures show embodiments of the present invention; FIG. 1 is a block diagram of I'll', and FIG. 2 is a block diagram showing the entire configuration. 1.2...Transmission line (optical transmission line), 1a, 2a...
- Receiving side, 1b, 2b... Transmitting side, 3, 3. ~35
...I/F (interface), 4...Main device (communication device), 5□~54...Terminal device (communication device), 11a, 11b, 12a, 12b HHH+ optical connector, 14a , 14b...0 (photoelectric converter), 15a, 15b...VO (electronic converter), 17
...Device (communication device), 18a to 18c...O
R gate.

Claims (1)

[Claims] In a communication system including a plurality of communication devices that communicate with each other via a common transmission bus, first and second optical transmission lines are provided as the transmission bus to transmit optical signals in opposite directions, Each of the communication devices is interposed in the middle of each of the optical transmission lines, and each signal received from the receiving side of each of the optical transmission lines is combined to form a received signal, and each transmitted signal is branched to transmit each of the optical signals. At the same time as transmitting to the transmitting side of the transmission line, each signal received from the receiving side of each of the optical transmission lines is individually amplified, combined with the transmitted signal and transmitted to the corresponding transmitting side of each optical transmission line. An optical transmission communication system characterized by: