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R & D Review


No.105 October 2008

Industrial High Reliability Ethernet Equipment
- Specification of the Main Equipment and Example of a Network Construction -

In recent years, with the spread of the Internet, a movement to apply Ethernet has advanced rapidly, from the main solution for office and home network, to network construction for industrial systems. However, the specification of Ethernet equipment is unsuitable for networks of industrial systems because it has generally been a solution for mainly office and home networks. In 1983 , prior to other companies, we introduced the first domestic transceiver for 10 BASE-5 to the market. Since then, taking advantage of technologies accumulated through commercializing, we have supplied industrial high-reliability Ethernet equipment by fully utilizing the merits of the Ethernet. In this report, specification of the industrial highly reliable Ethernet equipment and examples of network constructions are introduced.
[Key words] Ethernet, Industrial Use, Reliability, Long-term Stable Supply, Environment, Optical Fiber, Traceability, Trouble Analysis

High Speed Communication System for Emergencies Using Long-distance GHz Leaky Coaxial Cables

Long-distance leaky coaxial cables (LCX) that can transmit radio waves of the GHz band used for interactive high-speed and large capacity communication is researched and developed for underground and tunnel disasters. At the same time, the robot remote control system, the telemeter system, and the image transmission system are researched and developed using leaky coaxial cables. The application communication experiment was conducted in an open space and in an area shaded by a building where the environment was close to the actual site. Operation in each place was confirmed.
[Key words] Leaky Coaxial Cable, LCX, GHz Band, Wireless LAN, High-speed and Large Capacity Communication

Road-to-Vehicle Communication Systems Using Wireless LAN Technologies
- Application of Wireless LAN Technology in a Disaster Prevention System -

In recent years communication using the technology of wireless LAN is spreading rapidly. Moreover, it is not only used in the home and office but it is now also used in trains and cars.
We have developed a road-vehicle-communication system using wireless LAN technology conforming to IEEE802 .11 g. Unlike conventional information socket system connected to a connector, the purpose of this system is to transmit large capacities of information between vehicles mounted with wireless LAN antennas seamlessly to a wireless LAN at an access point set up along the road. Communication using this system is possible not only for vehicles parked on road shoulders but seamless communication is also possible for moving vehicles. Real-time transmission of picture images, calls on the mobile phone, access to server data can be made using this system. The system enables patrol cars to instantly send on-site disaster situations to headquarters, allowing accurate initial response to disasters.
This article reports on the outline of the network structure and the machinery used in this system.
[Key words] Wireless LAN, Information Socket System, IEEE802 .11 g, Road-to-vehicle Communication, Access Point, Moving Picture Transmission, Seamless, Disaster Prevention System, Patrol Car

Pilot Experiment of remote education in Rural Areas of Thailand using Long- distance Wireless LAN Bridge System
- Success in Introducing a Remote Education Model System in Digitally Divided Areas -

We, Mitsubishi Cable Industries, Ltd., obtained a certification of Technical Regulation Conformity based on "Relieving of antenna profit conditions for low-power data communication system (wireless LAN)" stipulated by revision of the Radio law.
From 2002 , we have started sales of Wireless LAN Systems that realized a 40 km long distance communication, combined with high gain antennas and high quality cables in the 2 .4 GHz band based on IEEE802 .11 b. However, the access speed of this system was limited to approx. 5 Mbps. A technical standard conformity proof was newly acquired for wireless LAN based on IEEE802 .11 g in 2006 , and a system having twice as much transmission speed was developed.
Mitsubishi Cable Industries and NTT Advanced Technology Corporation performed a pilot experiment on remote education for rural areas in southern Thailand from Nov.2007 to Jun.2008 supported by The Asia Pacific Telecommunity (APT). The Benchamarachutit College, approx. 23 km away from the Walailak University of southern Thailand Nakhon Si Thammarat was relayed, and then approx. 15 km away Princess Chulaborn’s College was further connected by wireless LAN. The system proved to be applicable to telecom infrastructures for remote education. The long-distance wireless LAN bridge system was recognized to be an effective system as a telecom infrastructure for distant education by this success. In the near future, the LAN bridge system is expected to be introduced as a telecom infrastructure for remote education to rural areas in the troubled regions of southern Thailand where educational opportunities are scarce.
[Key words] Long-Distance Wireless LAN, IEEE802 .11 g, Brige, Wireless, Remote Education

Development of High-reliability Ethernet Switching-hub for Heavy Duty Industries

We have provided various High-Reliability Ethernet equipments used in mission critical fields. There is a growing need for a switching-hub with an automatic self-recovery function to prevent transmission failures, as Ethernet and TCP/IP technology is recently becoming widely used in industrial business scenes. As an industrial Ethernet switching-hub, we have developed a new switching-hub with unique functions, such as an automatic self-recovery function to prevent transmission failures. We summarize the details on these unique functions.
[Key words] Switching hub, Network, High reliability , Trouble Recovery

10 kW Long-length Cables for Laser Transmission Incorporated with Eight Optical Fibers

Recently, high-power and high-quality lasers have been widely used in material machining and processing, microlithography, precise measurement, and medical science. Fiber laser systems are especially becoming more high-powered and have higher quality. However, at the processing site, the laser oscillator and the work area is separately laid out. Therefore, long distance transmission by optical fibers is in urgent demand. At the site, usually several optical fibers are used and compactness must be considered. As for the layout site, the beam quality should not deteriorate (e.g. transmission loss increase and change in the beam profile) by bending, pulling, from impacts and temperature change. In response to the above-mentioned demands, we developed an optical fiber cable with; (1) processed fiber ends for high-power, (2) incorporated fibers, and (3) beam quality degradation prevention measures.
[Key words] Laserguide, Fiberlaser, High Power Laser, Multiplex Optical Fiber Cable, Silica Cone, Multi-mode-fiber, Transmission

Optical Fiber Sheets -For the Next Generation-

Recently, the optical fiber network is expanding to the home. The traffic of the data communication from personal computers, television and cell phones is showing exponential increase. The traffic of data throughput between the servers will expand and the data transfer speed in the servers will exceed the maximum electronic speed. Therefore, wiring methods in the servers will be converted from electrical wires to optical fibers. We have developed optical fiber sheets with free wiring to be used inside optical connections. In this paper, we introduce examples, wiring style of optical fiber sheet, coil sheets, and coupler sheets.
[Key words] Optical Fiber Sheet, Flexible Print Circuit, Fiber Coil, Fiber to the home, Coupler Sheet, Shuffle Sheet, Optical Bus, Reliability, Telcordia

Development of Bending Loss Insensitive Fiber for 5 mmR

We have developed a bending loss insensitive fiber-TOUGHBEND- that has many advantages for optical connections in compact equipments and wiring in the home. The conventional optical fiber needs a large bending radius such as 30 mm, making fiber arrangement among optical components difficult. On the other hand, our bending loss insensitive fiber - TOUGHBEND - has no excess loss even though the bending radius is only 5 mm. Furthermore, - TOUGHBEND - may easily replace conventional fibers because of their size compatibility. In this article, we report on the structure and characteristics of three types of the bending loss insensitive fibers (single mode type:TOUGHBEND-S, and -S+ , multimode type:TOUGHBEND-G).
[Key words] Bending Loss Insensitive Fiber, Bending Radius of 5 mm, Single Mode Fiber, Multi Mode Fiber

Prediction of Bending Durability by Using Computer Aided Engineering (CAE) Technologies for High-frequency Coaxial Cable Products

Recently demand for high-frequency coaxial cables, mainly applied to the base stations of mobile communications, represented by the cellular phone, is increasing with the expansion of coverage areas. And since they are applied for other various uses, for example wireless communications, train radio systems, and broadcast systems; these products are wide-ranging in variety. Moreover, as needs from each product market increase for a higher performing product, it is essential for us to shorten the time taken for product designing and development.
We have developed a technique for predicting the bending durability of high-frequency coaxial cables without having to produce prototypes, by leveraging the Coffin-Manson rule, which are known as empirical rules in low cycle fatigue of metal material, and one of the CAE technologies (simulation using the structural analysis by the nonlinear finite element method). We have been able to optimize cable structures in the design phase, to raise the reliability of a product, and to decrease a large number of trial productions. Accordingly, we are prepared to quickly respond to the ever-changing market needs.
[Key words] High-frequency Coaxial Cable, Low Cycle Fatigue, Plastic Strain, Coffin-Manson Rule, Nonlinear Finite Element Analysis

Precipitation-hardened Copper Alloy Trolley Wires for the New Shinkansen Lines

We have started the delivery of Precipitation-Hardened Copper alloy (PHC) trolley wires for the new Shinkansen lines, Tohoku Shinkansen (between Hachinohe and Shin-Aomori) and Kyushu Shinkansen (between Hakata and Shin-Yatsushiro).
This article introduces the PHC trolley wires used in the new Shinkansen lines.
[Key words] Trolley Wire, Copper Alloy, Abrasion Resistance

Development of D.U.C.C.® Conductor for Audio Cables

Conventionally, high fidelity sound was pursued by increasing the purity and crystal size of copper used in audio cables in order to avoid impurities in transmitting audio signals in electrical channels. For the purpose of developing an ideal conductor for audio cables, we have investigated the state of the impurities in high purity copper conductors and if the conductors have physical directionality.
We have found that the crystalline lattice shows strong crystal orientation in the cross section of the conductor. Moreover, we have newly found that impurities, considered only to exist in boundaries of crystal grains, exist also in the inside of a crystal grain.
[Key words] Audio Cable, Speaker Cable, RCA Cable, Power Cable, 6 N, 7 N, D.U.C.C., High Purity Copper

Portable Diagnosis Testers for Live-line High-voltage Cables
- Live-line Measurement of Sheath Insulation Resistance and Shield Resistance -

There are two methods to diagnose degradation in high-voltage cables. One is taking measurements on stopped lines, and the other is taking measurements in live-lines. The former achieves high precision diagnosis, but lines must be stopped. The latter does not require lines to be stopped, but initial costs are high, and detections of very low-level signals are required, which are susceptible to environmental noise. We introduce portable testers that measure the sheath insulation resistance and shield resistance of live-lines with high precision, instead of measuring the main insulation. Detecting degraded cables with these testers can prioritize cables to be checked by the DC leakage current method. This boosts up reliability in the maintenance of high-voltage cables in plants and factories, and is laborsaving.
[Key words] Live-Line Diagnosis, High-Voltage Cable

Development of EPDM with Excellent Chlorine Water Resistance
- EPDM: Degradation by Hypochlous Acid and Development of Excellent Resistance to Chlorine Water -

Many kinds of rubber materials have been used as seal products for various water supplying equipments, and among them, ethylene propylene rubber (EPDM) is frequently used. However, EPDM is degraded by residual chlorine in city water, and there have been problems such as coloring of water and leakage due to cracks in the packing. Recently, EPDM is used in more severe conditions, and heat and chlorine water resistance of EPDM needs to be improved further more. In this report, degradation of EPDM in chlorine water is described and development of new EPDM materials with higher chlorine water resistance and heat resistance are introduced.
[Key words] EPDM, Hypochlorous Acid, Heat Resistance, Chlorine Water Resistance

Characteristics of SUNFLON® U-seals

The SUNFLON U-seal is an advanced all-purpose seal consisting of a SUNFLON U-ring and a corrosion resistant stainless steel spring. SUNFLON U-seals cannot be damaged by most chemicals and solvents, and may be used under wide temperature ranges, various pressure ranges from vacuum to high pressure, and for reciprocating and static applications. However recent equipments tend to be operated under extremely high pressure and high speed, and therefore, SUNFLON U-seals need to be stable in low torque for a long period of time and under severer conditions.
In this report, characteristics of standard SUNFLON U-seals and specially designed SUNFLON U-seals for use under severer conditions are introduced.
[Key words] SUNFLON U-seal, Heat Resistance, Cold Resistance, Chemical Compatibility, Wear Resistance

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