No.39 (2005)

Yokogawa periodically publishes the Yokogawa Technical Report, which contains articles that take a detailed look at the technologies employed in Yokogawa's products. At this site you will find links to all of the reports that have been published since 1997 as well as links to PDF files containing the full text of selected articles from each issue.



  • NAGASHIMA Akira*1

*1 Director, Chief Technology Officer
    Executive Vice President of
    Corporate Research and Development Headquarters


  • OGITA Eiji*1
  • AMARI Toyofumi*1
  • YOSHIZAWA Atsushi*1
  • WAKAMATSU Muneaki*1
  • MATSUMOTO Akira*1

*1 Measurment standards Laboratory, Corporate Research and Development Headquarters (Kofu)

It is the responsibility of instrument manufacturers to maintain the traceability of measuring instruments and testing equipment to national standards, in order to ensure the consistency and reliability of measured data. This paper discusses traceability with a focus on electrical, optical, pressure and temperature measurements. The DC voltage standard is a Zener-type standard voltage source, the DC resistance standard is a Yokogawa-manufactured standard resister, the AC voltage and AC current standards are AC/DC thermal voltage and current transfer standards, the optical power standard is a calorimeter, the optical wavelength standard is a frequency-stabilized He-Ne laser, the pressure standard is a deadweight pressure balance, and the temperature standards are a Pt-Co RTD, SPRT and R-thermocouple. Measurement traceability is maintained by means of periodical calibration.

Yokogawa Electric Corporation is an accredited calibration service provider in the categories "Electrical" and "Pressure" of the Japan Calibration Service System, a measurement law-based traceability system introduced in 1993.


  • IWASE Hisashi*1
  • ITOU Osamu*1
  • TACHIBANA Katsuya*1

*1 Communications and Measurement Business Headquarters

We have developed the WT3000 Precision Power Analyzer, which features the world's highest measurement accuracy of ±0.02% of reading and a measurement bandwidth of 0.1 Hz to 1 MHz as well as DC signals. The WT3000 can be equipped with four input elements, as against three with its predecessor, the WT2000. Also, it is possible to measure the efficiency of a DC-input three-phase inverter with one WT3000 unit, thereby enabling highly accurate measurement of the efficiency of inverters installed on electric vehicles and so on. Its predecessor used a conventional LED, but the WT3000 uses a large-sized LCD enabling the WT3000 to display measured values in various forms, including waveform, for greater operability. This paper outlines these key features.


  • YAGYU Hiroshi*1
  • NAKAMURA Hajime*1
  • OOTA Kouji*1
  • TONOSAKA Naoki*1

*1 Communications and Measurement Business Headquarters

We have developed the WE500/WE900 measuring stations for the WE7000 series of PC-based measurement instruments. The WE500/WE900 have inherited the conventional plug-and-play architecture and high-speed data transmission function, and achieved even more advanced functionality and higher performance while maintaining compatibility with the conventional measurement modules. Along with the “embedded module” function that performs internal measurement data processing and autonomous operations, the WE500/WE900 come preinstalled with communication functions based on USB and Ethernet interfaces capable of transmitting data at a maximum rate of 480 Mbps.


  • DEMACHI Kouji*1
  • AKABANE Kuniharu*1
  • NAKAJIMA Takeshi*1
  • YOKOI Toyoaki*1

*1 Industrial Automation Systems Business Center

The Vnet/IP is a real-time plant network system for process automation based on the 1-Gbps Ethernet communications system. The Vnet/IP system implements transport protocols optimized for process automation on top of the UDP protocol, simultaneously realizing real-time operability and a high degree of reliability and usability. This system will be used as the core network for CENTUM distributed control systems and has been put forward to the International Electrotechnical Commission (IEC) for approval as a new international standard.


  • NAGAI Koji*1
  • HASHIZUMI Kazuhio*1
  • MURAKAMI Tatsuhiro*1
  • SAITO Yoji*1

*1 Field Equipment Development and Engineering Department

Yokogawa released the 5502 analog current to pneumatic converter and 5503 valve positioner in 1961, and the PK200 analog current to pneumatic converter and VP200 valve positioner in 1992. These models have been chosen for many plant control applications. Furthermore, it released the YVP110 FOUNDATION Fieldbus valve positioner in 1999, endeavoring to improve the efficiency and usability of positioners and to reduce lifecycle cost through online diagnostics. Meanwhile, demand for FOUNDATION Fieldbus to pneumatic converters has grown as 1) pneumatic signals are now used for final control elements even in fieldbus instrumentation, 2) there are requests to convert plants instrumented with pneumatic control devices into fieldbus-networked plants, and 3) many instruments need to be driven directly by pneumatic pressure. We therefore developed the YPK110 fieldbus to pneumatic converter. This paper introduces the structure, control method, and online diagnostics of the YPK110.


  • OZAKI Yoshihisa*1
  • HARASHIMA Shigeo*1

*1 Medical Solutions Center, ETS Development Division

In recent years, along with the progress in digitization of medical images, PACS has spread primarily in the radiology department, and this has encouraged filmless data management in medical institutions. Furthermore, an expansion of medical image digitization out of the radiology department such as laboratory and clinical departments facilitates the availability of digitized images in surgery and research departments as well as in hospital wards. This has lead to an issue of managing and utilizing the enormous volume of image data that is generated.

The "ShadeQuest" integrated image information system, which comprehensively manages image data generated in the medical institution, allows referring image data quickly and certainly, while ensuring storage security, data centralization and consolidation. The "ShadeQuest" contributes to improvement in patient services and medical service quality through speed-up in diagnoses and work efficiency advancement.


  • HAYASHI Hisanori*1
  • OSHIMA Yasumi*1
  • TADA Hiroaki*2
  • OZAWA Yoshinori*3

*1 Medical Solutions Headquarter
*2 Department of Radiography, Chiba Rousai Hospital
*3 Department of Neurological Surgery, Chiba Rousai Hospital

Brain disease is one of the three major diseases in Japan, and the most serious case is subarachnoid hemorrhage where eighty-five percent is caused by the rupture of cerebral aneurysms. It is estimated that about 5 percent of adults are unaware of having unruptured cerebal aneurysms, which makes early detection of cerebal aneurysms a significant issue. Although three-dimensional magnetic resonance angiography (3D-MRA) is generally used in screening for cerebral aneurysms, the detection of cerebral aneurysms requires considerable skill and experience due to the complexity of cerebrovascular networks. This study is intended to verify the effectiveness of our computer-aided diagnosis (CAD) system in clinical use, which we have developed in collaborative research with Chiba Rousai Hospital for detecting cerebral aneurysms applying 3D-MRA data. In order to detect cerebral aneurysms, we firstly developed an image filtering method for extracting cerebrovascular areas and then examined the vessel diameter from the corresponding cerebrovascular area, and finally reviewed the characteristic values for cerebral aneurysms detection.

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