JP2009038545A - Wireless lan explosion-proof relay and communication system in dangerous area - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless LAN explosion-proof relay which is applied to wireless communication by a wireless LAN in a dangerous area in an oil factory and a photochemical factory, etc., can perform long distance wireless relay in the dangerous area over a wide range, and a communication system in the dangerous area utilizing such a wireless LAN explosion-proof relay. <P>SOLUTION: A wireless LAN two-way communication unit 10 which performs two-way communication by the wireless LAN is stored in a first chassis 51 made into pressure-proof and explosion-proof structure, an antenna main body 40 connected to the wireless LAN two-way communication unit 10 by an antenna cable 41 extended to the outside of the first chassis 51 is stored in a second chassis 52 made into the pressure-proof and explosion-proof structure using a radio transmission material for transmitting a radio signal transmitted and received by the antenna main body 40 for at least a part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention provides a wireless LAN (Local
The present invention relates to a wireless LAN explosion-proof repeater that can be applied to wireless communication by an area network and enables long-distance wireless relay, and a communication system in a danger zone using such a wireless LAN explosion-proof repeater.

  For example, in refineries and petrochemical factories, non-hazardous areas are used to perform business management and maintenance of manufacturing equipment in hazardous areas where flammable gases or flammable liquid vapors may exist. In addition, a management facility is provided in the center, and various data are transmitted and received between the management facility and various facilities installed in the hazardous area for centralized management.

In recent years, wireless LAN has attracted attention for such data transmission / reception. According to the wireless LAN, it is not necessary to install a communication cable, which is advantageous in terms of cost. Under such circumstances, the applicant of Patent Document 1 can communicate a large amount of data safely and efficiently, and is a wireless LAN explosion-proof relay suitable for use in such a dangerous area. Proposed a vessel.
JP 2006-197402 A

Here, the repeater performs wireless communication by wireless LAN with a transmitter / receiver installed in a dangerous area, but a wireless LAN server installed in a non-hazardous area is a communication cable such as an optical cable. Communicating over a wired LAN via For this reason, the installation location of the repeater is determined in consideration of the distance that can be relayed to the transmitter / receiver that is the counterpart of wireless communication by wireless LAN. If the relay distance at this time cannot be secured sufficiently, Therefore, it is necessary to install the repeater close to the counterpart transceiver. For this purpose, the communication cable must be extended and installed, and the advantages of the wireless LAN are impaired.
In addition, when a sufficient relay distance cannot be secured, it is possible to further increase the overall relay distance by using a plurality of repeaters by interposing a repeater between the transmitter and the receiver. However, in this case, the transmission capacity decreases every time relaying is performed, and the decrease in transmission capacity becomes more remarkable as the number of repeaters increases.

  Hazardous areas, such as refineries and petrochemical plants, are generally widespread. For this reason, it has been pointed out that it is difficult to cover all of a wide range of dangerous areas with only the repeater proposed in Patent Document 1 if a sufficient relay distance cannot be secured, and a longer distance can be relayed. There is a need for a wireless LAN explosion-proof repeater.

  The present invention has been made in view of the above circumstances, and is applied to wireless communication by wireless LAN in a dangerous area such as a refinery or a petrochemical factory, and a long distance wireless relay in a wide range of the dangerous area is performed. An object of the present invention is to provide a wireless LAN explosion-proof repeater that can be used, and a communication system in a hazardous area using such a wireless LAN explosion-proof repeater.

  The wireless LAN explosion-proof repeater according to the present invention accommodates a wireless LAN bidirectional communication unit that performs bidirectional communication by wireless LAN in a first casing having a pressure-proof explosion-proof structure, The antenna main body is connected to the wireless LAN bidirectional communication unit by an antenna cable that is extended while maintaining the explosion-proof structure on the outside, and at least a part of a radio wave transmitting material that transmits radio signals transmitted and received by the antenna main body The antenna main body is housed in the second casing that is used for the above-mentioned and that has the explosion-proof structure while maintaining the explosion-proof structure.

  The wireless LAN explosion-proof repeater of the present invention configured as described above can freely determine the installation position of the antenna body according to the directivity of the antenna body, and enables long-distance wireless relaying. In order to enable long-distance wireless relaying, the antenna body is preferably a directional antenna.

  The wireless LAN explosion-proof repeater according to the present invention includes a switching hub connected to the bidirectional communication unit in the first casing together with the bidirectional communication unit so that various network communication devices can be connected. It is good also as the structure accommodated.

  Further, the communication system in the hazardous area according to the present invention includes a wireless LAN bidirectional communication unit for performing bidirectional communication by wireless LAN in a first casing having a pressure-proof explosion-proof structure. The antenna main body is connected to the wireless LAN bidirectional communication unit by an antenna cable that is extended while maintaining the explosion-proof structure on the outside, and at least a part of a radio wave transmitting material that transmits radio signals transmitted and received by the antenna main body The antenna body is housed in a second housing that is used for the explosion-proof structure while maintaining the explosion-proof structure, and is installed in a hazardous area at a certain distance. A wireless LAN explosion-proof repeater, a wireless LAN server installed in a non-hazardous area and connected to one of the pair of wireless LAN explosion-proof repeaters; Installed in insurance district, it is constituted comprising a network communication device is a pressure-resistant explosion-proof structure connected to the other or both of the pair of wireless LAN explosion-proof repeater.

  According to the communication system in the hazardous area of the present invention configured as described above, long-distance wireless relay is enabled by the pair of wireless LAN explosion-proof repeaters installed in the dangerous area.

  As described above, the present invention enables long-distance wireless relaying in wireless communication using a wireless LAN in a hazardous area.

  Hereinafter, preferred embodiments of the present invention will be described.

[Wireless LAN explosion-proof repeater]
First, an embodiment of a wireless LAN explosion-proof repeater according to the present invention will be described.
FIG. 1 is an explanatory diagram showing an outline of an embodiment of a wireless LAN explosion-proof repeater according to the present invention.

  A wireless LAN explosion-proof repeater 1 shown in FIG. 1 includes a wireless LAN bidirectional communication unit 10 that performs bidirectional communication using a wireless LAN and a power supply unit 30 that supplies necessary power in a first housing 51. It is housed.

The first housing 51 can be a metal fully closed container having a flameproof structure and made up of a container body and a lid.
The first casing 51 is provided with cable joints 511, 512, and 513 for maintaining the explosion-proof structure and extending the cables outside the first casing 51. These cable joints 511, 512, and 513 are provided with sealing means such as cable packing made of a rubber cylindrical member, for example, and can be sealed in a state where the cable is inserted.

The antenna main body 40 is connected to the bidirectional communication unit 10 accommodated in the first casing 51 by an antenna cable 41 extended from the cable joint 511 to the outside of the first casing 51.
Similarly, the power cable 31 connected to the power supply unit 30 extends from the cable joint 513 to the outside of the first housing 51.
In the illustrated example, power is supplied by the PoE (Power over Ethernet / “Ethernet” is a registered trademark) method, and the bidirectional communication unit 10 and the power supply unit 30 are connected by the PoE power supply cable 13. Has been. The communication cable 11 such as an optical cable is connected to the power supply unit 30 and extends from the cable joint 512 to the outside of the first housing 51. Thereby, for example, as shown in FIG. 2 to be described later, the wireless LAN explosion-proof repeater 1 can be connected to the wireless LAN server 101 by connecting the communication cable 11 to the switching hub 102. .

The specific configuration of the wireless LAN bidirectional communication unit 10 is not particularly limited as long as the wireless LAN bidirectional communication unit 10 can perform bidirectional communication using the wireless LAN based on the LAN signal transmitted and received by the antenna body 40. For example, in accordance with a communication standard such as IEEE 802.11, in a communication system to be described later (see FIG. 2 and the like), bidirectional communication by a wireless LAN between a pair of wireless LAN explosion-proof repeaters 1a and 1b, or a wireless LAN server Two-way communication with a wired LAN or a wireless LAN with the 101, and further two-way communication with the transmitter / receiver 62 via the wireless LAN access point 61 connected to the switching hub 20, various networks. Any device capable of realizing bidirectional communication with the communication device 63 may be used.
In addition, the wireless LAN bidirectional communication unit 10 includes an optical / electrical converter that mutually converts an optical signal and an electrical signal so that communication can be performed using either the optical signal or the electrical signal. You can also.

On the other hand, the antenna body 40 connected to the wireless LAN bidirectional communication unit 10 by the antenna cable 41 is accommodated in the second casing 52 having the explosion-proof structure so that the pressure-proof structure is maintained. Yes.
The second casing 52 shown in FIG. 1 is provided with a cable joint 523 similar to the cable joints 511, 512, and 513 provided in the first casing 51. The antenna cable 41 is drawn into the second housing 52 by the cable joint 523 so that the explosion-proof structure of the second housing 52 is maintained, and the antenna cable 41 is connected to the antenna body 40. .

The second casing 52 includes a radio wave transmitting member 521 made of a radio wave transmitting material that transmits a radio wave signal (LAN signal) transmitted and received by the antenna main body 40, and a metal base 522. As a radio wave transmitting material for forming the radio wave transmitting member 521, a material capable of suppressing transmission loss of radio wave signals is appropriately selected.
The radio wave transmitting member 521 can be formed as a cylindrical member whose one end is closed so as to cover the periphery of the antenna body 40. Then, the antenna body 40 is inserted through the opening on the other end side of the radio wave transmitting member 521, and the opening of the radio wave transmitting member 521 is closed by the base 522 to which the base of the antenna main body 90 is fixed. The second casing 52 has a flameproof structure.

The antenna body 40 is preferably a directional antenna with high directivity.
As the directional antenna, for example, an 8-element Yagi type can be used.

The wireless LAN explosion-proof repeater 1 as described above is configured by installing a pair of wireless LAN explosion-proof repeaters 1 at a certain distance so that, for example, a flammable gas such as a refinery or a petrochemical factory. In addition, two-way communication by wireless LAN is possible in a dangerous area where there is a risk that flammable liquid vapor may exist.
And the antenna main body 40 is independently accommodated in the 2nd housing | casing 52 used as the explosion-proof structure, and the installation position of the antenna main body 40 can be freely defined according to the directivity of the antenna main body 40. For this reason, in particular, by using a directional antenna for the antenna body 40, it is possible to perform wireless relay over a long distance of up to about 1,000 m. Furthermore, since a sufficient relay distance can be ensured without interposing a plurality of repeaters, large-capacity data can be transmitted / received to / from a remote place without reducing the transmission capacity.

[Communication system in hazardous area]
Next, an embodiment of a communication system in a hazardous area according to the present invention will be described.

(First embodiment)
FIG. 2 is a block diagram showing an outline of the first embodiment of the communication system in the danger zone according to the present invention.
The communication system of the present embodiment is for performing wireless communication using a wireless LAN in a hazardous area where there is a possibility that flammable gas, flammable liquid vapor or the like may exist, such as a refinery or a petrochemical factory. Is. A wireless LAN between a wireless LAN server 101 installed in a management facility 100 such as a measurement room or office in a non-hazardous area and a transceiver 62 or various network communication devices 63 installed in the dangerous area. By this, various data can be transmitted and received.

  In the example shown in FIG. 2, a pair of wireless LAN explosion-proof repeaters 1a and 1b are installed in a hazardous area at a certain distance. In the communication system according to the present embodiment, the communication in the dangerous area is relayed wirelessly by the pair of wireless LAN explosion-proof repeaters 1a and 1b, and it is not necessary to install a communication cable therebetween.

  Here, the configuration of the wireless LAN explosion-proof repeater 1 (1a, 1b) is as described above, and the antenna main body 40 of each wireless LAN explosion-proof repeater 1a, 1b has its direction according to each other's directivity. The installation position can be freely determined. For this reason, in particular, by using a directional antenna for the antenna body 40, it is possible to perform wireless relay over a long distance of up to about 1,000 m.

  In the example shown in FIG. 2, a communication cable 11 such as an optical cable is laid from a non-hazardous area to a dangerous area. The communication cable 11 connects one wireless LAN explosion-proof repeater 1a installed in the hazardous area to the wireless LAN server 101 installed in the management facility 100 via the switching hub 102.

The other wireless LAN explosion-proof repeater 1b can be connected to various network communication devices having a pressure-proof explosion-proof structure.
In the illustrated example, the wireless LAN bidirectional communication unit 10 built in the wireless LAN explosion-proof repeater 1b is connected to a wireless LAN access point 60 and a network communication device (a network other than the wireless LAN access point 60 via a switching hub 20). Communication equipment) 63 is connected. The wireless LAN access point 60 is wirelessly connected to the transceiver 62.
As the transmitter / receiver 62, for example, a computer to which a wireless LAN adapter is attached, a PDA (Personal Digital Assistant) having a transmission / reception function, or the like is used. As the network communication device 63, for example, a network camera that has a network function and can be directly connected to the network is used.

These devices have an explosion-proof construction so that they can be used in hazardous areas. For example, as the wireless LAN access point 60, the wireless LAN proposed in Japanese Patent Application No. 2005-8297 filed earlier by the present applicant is used. A LAN explosion-proof repeater or a wireless LAN explosion-proof repeater proposed in Japanese Patent Application No. 2006-142110 can be used. As the switching hub 20, for example, an explosion-proof switching hub proposed in Japanese Patent Application No. 2006-142110 filed earlier by the present applicant can be used.
Although not shown, the wireless LAN access point 60 and the network communication device 63 can be connected to the wireless LAN explosion-proof repeater 1a connected to the wireless LAN server 101 via the switching hub 20. .

  As described above, in the communication system of the present embodiment, various data are transmitted and received between the wireless LAN server 101 in the non-hazardous area and the transceiver 62 and various network communication devices 63 in the dangerous area. A long distance can be relayed wirelessly by a pair of wireless LAN explosion-proof repeaters 1a and 1b installed in the hazardous area. And according to this embodiment, since a sufficient relay distance can be secured without interposing a plurality of repeaters, large-capacity data can be transmitted to and received from a remote place without reducing the transmission capacity. It becomes possible. Therefore, even when an image photographing device such as a network camera is connected as the network communication device 63, large-capacity image data can be transmitted from a remote place to the wireless LAN server 101 without any problem.

(Second embodiment)
FIG. 3 is a block diagram showing an outline of the second embodiment of the communication system in the danger zone according to the present invention.
The present embodiment differs from the first embodiment described above in that the wireless LAN explosion-proof repeater 1a and the wireless LAN server 101 are connected by a wireless LAN. That is, in the present embodiment, in the management facility 100, the wireless LAN adapter 61 is connected to the wireless LAN server 101, and the bidirectional communication unit 10 incorporated in the wireless LAN explosion-proof repeater 1a is connected to the wireless LAN server 101 via the switching hub 20. A wireless LAN access point 60 is connected. Thus, the connection between the wireless LAN explosion-proof repeater 1a and the wireless LAN server 101 may be either a wired LAN or a wireless LAN.

  When the wireless LAN explosion-proof repeater 1a and the wireless LAN server 101 are connected by a wireless LAN, the wireless LAN adapter 61 installed in the non-hazardous area does not need to have a pressure-proof explosion-proof structure. Various non-explosion-proof wireless LAN adapters can be used. On the other hand, as the wireless LAN access point 60 and the switching hub 20 installed in the dangerous area, for example, as in the first embodiment described above, the wireless LAN explosion-proof repeater or explosion-proof type previously proposed by the present applicant. A switching hub or the like can be used.

  This embodiment is different from the first embodiment described above in the above points, and others have a common configuration, and thus description of the other configurations is omitted.

(Third embodiment)
FIG. 4 is a block diagram showing an outline of the third embodiment of the communication system in the danger zone according to the present invention.
In the example shown in FIG. 4, two pairs of wireless LAN explosion-proof repeaters 1a, 1b, 1c, and 1d are installed in the hazardous area at a certain distance from each other. That is, two wireless LAN explosion-proof repeaters 1b and 1c are installed between the pair of wireless LAN explosion-proof repeaters 1a and 1d so as to be paired with each wireless LAN explosion-proof repeater 1a and 1d.
Thereby, in the communication system of the present embodiment, communication between the wireless LAN explosion-proof repeaters 1a and 1b and between the wireless LAN explosion-proof repeaters 1c and 1d is relayed wirelessly.

  As described above, the present embodiment differs from the first embodiment described above in that a plurality of wireless LAN explosion-proof relays are further provided between the pair of wireless LAN explosion-proof repeaters 1a and 1d installed in the dangerous area. The devices 1b and 1c are added, and the wireless LAN explosion-proof repeater 1 is paired. In this embodiment, the wireless LAN explosion-proof repeater 1b in one pair and the wireless LAN explosion-proof repeater 1c in the other pair are connected to the communication cable 11 via the explosion-proof switching hub 20 as described above. Are connected, and the relay distance as a whole is extended.

Here, the wireless LAN explosion-proof repeater 1b in one pair and the wireless LAN explosion-proof repeater 1c in the other pair are connected with a communication cable 11 in a wired manner, instead of the explosion-proof switching hub as described above. The wireless LAN explosion-proof repeater proposed in Japanese Patent Application No. 2005-8297 filed earlier by the present applicant and the explosion-proof wireless communication means proposed in Japanese Patent Application No. 2006-142110 via You can also connect with.
Further, the wireless LAN explosion-proof repeater 1 can be three pairs or more according to the required relay distance. Furthermore, in constructing the communication system of the present embodiment, the installation location of the wireless LAN explosion-proof repeaters 1b and 1c may be a non-dangerous area adjacent to the dangerous area. In this case, the wireless LAN explosion-proof repeaters 1b and 1c may be installed with a pressure-proof explosion-proof structure, but the first and second casings 51 and 52 may be omitted to be a non-explosion-proof type.

  This embodiment is different from the first embodiment described above in the above points, and others have a common configuration, and thus description of the other configurations is omitted.

  Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. Nor.

  For example, in the embodiment described above, the wireless LAN explosion-proof repeater 1 is connected to various network communication devices via the explosion-proof switching hub 20, but the switching hub 20 is connected to the bidirectional communication unit 10. In addition, it is possible to adopt a configuration accommodated in the first casing 51.

  The present invention is not limited to plants such as refineries and petrochemical plants, but can be effectively applied to the entire equipment industry that requires explosion-proof equipment including food industry and steel industry. it can.

It is explanatory drawing which shows the outline of embodiment of the wireless LAN explosion-proof repeater which concerns on this invention. It is a block diagram which shows the outline of 1st embodiment of the communication system in the danger zone which concerns on this invention. It is a block diagram which shows the outline of 2nd embodiment of the communication system in the danger zone which concerns on this invention. It is a block diagram which shows the outline of 3rd embodiment of the communication system in the danger zone which concerns on this invention.

Explanation of symbols

1 (1a, 1b) Wireless LAN explosion-proof repeater 10 Bidirectional communication unit 20 Switching hub 40 Antenna body 41 Antenna cable 51 First housing 52 Second housing 521 Radio wave transmitting member 522 Base 60 Wireless LAN access point 62 transceiver 63 network communication device 100 management facility 101 wireless LAN server

Claims (4)

A wireless LAN bidirectional communication unit that performs bidirectional communication with a wireless LAN is accommodated in the first casing having a flameproof structure.
The antenna body is connected to the wireless LAN bidirectional communication unit by an antenna cable that extends while maintaining the explosion-proof structure outside the first casing,
The antenna main body is housed in a second casing that uses a radio wave transmitting material that transmits radio signals transmitted and received by the antenna main body at least in part, and that has a pressure-proof explosion-proof structure. A wireless LAN explosion-proof repeater characterized by   The wireless LAN explosion-proof repeater according to claim 1, wherein the antenna body is a directional antenna.   The wireless LAN explosion-proof repeater according to claim 1, wherein a switching hub connected to the bidirectional communication unit is accommodated in the first casing together with the bidirectional communication unit. A wireless LAN bidirectional communication unit that performs bidirectional communication by wireless LAN is accommodated in a first casing having a pressure-proof explosion-proof structure, and is extended outside the first casing while maintaining the pressure-proof explosion-proof structure. The antenna main body is connected to the wireless LAN bidirectional communication unit by an antenna cable, and a radio wave transmitting material that transmits radio signals transmitted and received by the antenna main body is used at least in part, and has a pressure-proof explosion-proof structure. The at least one pair of wireless LAN explosion-proof repeaters installed in the dangerous area at a certain distance, the antenna body is accommodated in the second housing while maintaining the explosion-proof structure.
A wireless LAN server installed in a non-hazardous area and connected to one of the pair of wireless LAN explosion-proof repeaters;
A network communication device installed in a dangerous area and having a pressure-proof explosion-proof structure connected to the other or both of the pair of wireless LAN explosion-proof repeaters;
A communication system in a hazardous area, comprising:

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