JP2732721B2 - Network equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

 [Object of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to plant control and
A plurality of transmitting / receiving stations for monitoring are connected to a bus-type optical multiplex transmission line (optical
Bus network)
It is related to the location .

[0002]

2. Description of the Related Art Conventionally, a loop type or a bus type has been used as an optical multiplex transmission line. However, since a transmission / reception device connected thereto is generally made for two-way communication, light emission is required. It has both a light receiving part and a light receiving part. On the other hand, in the case of a bus-type transmission line, when a continuous light emission event of the light emitting unit occurs due to a failure of a single station, the functions of all the transmission lines may be lost.

Further, since signals are transmitted and received between the transmitting station and the receiving station for handshaking, the involvement of the receiving station in the transmitting station cannot be physically excluded.
In other words, in the conventional transmission apparatus as described above, it is necessary to provide a station for bidirectional communication even for a station that does not need to output a signal to the network. It was necessary to consider the loss of function of the entire transmission path. Conventionally, a mechanism for stopping continuous light emission by self-diagnosis is provided for such a failure mode. However, the transmitting station and the receiving station are equivalent, and mutual independence is not ensured. In other words, since a control signal is output from the receiving station to the transmission path, there is a concern that the failure of a station installed exclusively for receiving may affect other transmitting and receiving stations.

[0004] For this reason, in order to apply the present invention to a part requiring separation and independence between systems, such as a safety protection system of a nuclear power plant, it is necessary to consider a method for separately securing independence.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems. By eliminating the light-emitting mechanism of the reception-only station, even if any failure mode of the reception-only station is assumed, A bus-type optical multiplex transmission line that satisfies the separation and independence requirements in terminal connection to a network that requires high reliability by enabling a network configuration in which other transmission and reception stations can operate completely independently. It is an object of the present invention to provide a non-interference type receiving apparatus. [Configuration of the Invention]

[0006]

FIG. 1 shows a configuration example of a bus-type optical multiplex transmission line (hereinafter, referred to as an optical bus network) using a non-interference type receiving apparatus according to the present invention. The optical bus network 1, a plurality of transceiver stations 2 are connected,
We are competing data required in the optical bus network 1 between each transceiver stations.

[0007] The interface device 3 with the optical bus network 1 provided in each transmitting / receiving station has a light emitting unit 3A for performing electro-optical conversion and a light receiving unit 3B for performing photoelectric conversion.
Data transmission and reception are performed while handshaking between the transmitting and receiving stations is secured by a control signal on the optical bus network 1.

The non-interference type receiving apparatus 4 of the present invention is connected to the optical bus network like the other transmitting / receiving stations 2, but has only the light receiving section 3B and does not participate in handshaking between the transmitting / receiving stations. Therefore, a control signal for handshake is transmitted from the non-interference type receiver 4 to the optical bus network 1.
And the light emitting unit 3A is not required. Therefore, it is not necessary to consider the loss of the function of the entire optical bus network due to the failure of the non-interference type receiving apparatus 4 (and the dedicated receiving station 5). Can be satisfied.

[0009]

The operation of the present invention will be described with reference to FIG.

When data is output from the control device A to the control device B using the optical bus network 1, a control signal of a bus use request is first output from the control device A. After receiving this, the control device B outputs a control signal indicating that reception preparation is completed. Control device A transmits necessary data after receiving the control signal of completion of reception preparation. Control device B
Then, it confirms that the data has been received normally, and outputs a control signal indicating normal reception completion. The control device A completes data transmission after waiting for a control signal reception indicating normal reception completion. If the data is not normally received on the control device B side, a data retransmission request is output instead of the normal reception completion, whereby the data transmission from the control device A is repeated.

At this time, all information (control signals and data) output to the optical bus network 1 is also received by the monitoring device C using the non-interference type receiving device of the present invention. Therefore, the monitoring device C can monitor all data on the optical bus network 1. On the other hand, since the monitoring device C does not have a light emitting mechanism, any hardware-software abnormality that may occur on the monitoring device C side is
The function of the optical bus network is not hindered, and control can be continued normally.

[0012]

FIG. 3 shows an example in which the non-interfering receiver according to the present invention is applied to a process computer of a nuclear power plant. The control devices A and B and C and D are connected to optical bus networks I and II of different security systems, respectively, and each optical bus network and the process computer 6 are required to be separated and independent. I do. Here, description will be given focusing on one optical bus network.

A plurality of controllers A and B and a process computer 6 are connected to the optical bus network I, and each controller exchanges data required for control via the optical bus network. The interface device 3 with the optical bus network I provided in each control device includes a light-emitting unit 3A that performs electric-optical conversion and a light-receiving unit 3 that performs photoelectric conversion.
B, and data is transmitted and received by the control signal on the optical bus network I so that the light emission between the control devices does not overlap. In addition, control is continued because data transmission is performed cyclically.

Since the optical bus network performs broadcast communication, all of these control signals and data are also input to the process computer 6 via the non-interference type receiver 4.
Data can be monitored on the process computer side. When the reception becomes abnormal on the process computer 6 side, the content of the monitoring item is held as the previous value, and the data is not updated until the next scan of the cyclic transmission. On the other hand, even if any abnormality occurs in the non-interference type receiver 4 or the process computer 6 as apparent, the optical bus networks I and I
Since there is no factor for outputting an abnormal signal on the I side, the independence of the network is not hindered. For this reason, it is also possible to connect the same process computer to the optical bus networks of different safety divisions. Furthermore, although not shown here, data exchange between optical bus networks of different security divisions is also feasible.

[0015]

As described above, according to the present invention,
Since it is possible to eliminate the loss of functions of the entire network due to an abnormality on the receiving station side, which is a problem when using an optical bus network, it is necessary to separate the terminals in a terminal connection to a network requiring high reliability. The optical bus network can be applied to the field.

[Brief description of the drawings]

FIG. 1 is a configuration example of an optical bus network using a non-interference type receiving apparatus of the present invention.

FIG. 2 is a configuration example in which the non-interference type receiving apparatus of the present invention is applied to an optical bus network of a control system.

FIG. 3 is a configuration example in a case where the non-interference type receiver according to the present invention is applied to an optical bus network of a safety protection system of a nuclear power plant.

[Explanation of symbols]

1 ... I and II are optical bus networks, 2 ... Transceiving stations, 3
... Interface devices, 3A, 3B, 3C ... light-emitting units, light-receiving units, and transmission controllers that constitute the interface devices, 4 ... non-interference type receiving devices, 5 ... dedicated reception stations, 6
Process computers, A to D: control devices, 10: main control devices constituting transmission / reception stations connected to the optical bus network.

Claims (1)

(57) [Claims] 1. A plurality of transmissions for controlling and monitoring a plant.
A network device that connects the receiving station to the optical bus network
In the device, the transmission and reception device provided for each of the transmission and reception stations,
Connected to the optical bus network and the optical bus network
Control the plant by sending and receiving data via
Control device and the optical bus network to which a plurality of transmitting / receiving stations are connected.
A light receiving unit that receives the output optical signal,
A photoelectric conversion unit that converts the received light signal into an electric signal,
And analyze the converted electrical signal as received data
-Interference-type reception having a transmission controller section for performing output
Connected to the optical bus network via a device,
Captures data output from the transmission controller
And a monitoring device for monitoring the plant.
Network device to do .