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Safety Studies on Hydraulic Proportional Valves With Electrical Position Feedback

Reinert D., Kimura T., Gorgs K.- J.

International Journal of Occupational Safety and Ergonomics

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2006

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Vol. 12, No. 1

105--115

EN

The authors analysed a proportional valve with electrical position feedback for its failure behaviour. Several failures were introduced into the feedback loop, especially into the 2 solenoids and the inductive position transducer. The behaviour of the valve for square and ramp reference signals was recorded and systematically analysed. It was shown that failures could be detected by monitoring the residual signal from the equipment under control or the residual signal from the sensor. It was possible to achieve the safe position within twice the normal response time of the valve by switching off the current of both solenoids. The application of these results for a new generation of safe proportional valves is discussed. The use of the results of these investigations obviates the need for redundancy of the electrical position monitoring arrangement in a safe proportional valve.

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International Research Into Occupational Safety and Health Protection

Meffert K., Reinert D.

International Journal of Occupational Safety and Ergonomics

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2006

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Vol. 12, No. 4

347--354

EN

Are we doing the right thing? Are we setting the right priorities for the future in occupational safety and health research? How does BG (Institution for Statutory Accident Insurance and Prevention) research compare nationally and internationally? As a mosaic of answers to these questions, this article explores international research on priorities in occupational research and analyses these against the backdrop of the nearly 1,000 research projects conducted by 9 institutions from 8 countries in the year 2003.

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Certification of Highly Complex Safety-Related Systems

Reinert D., Schaefer M.

International Journal of Occupational Safety and Ergonomics

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1999

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Vol. 5, No. 4

537--552

EN

The BIA has now 15 years of experience with the certification of complex electronic systems for safety-related applications in the machinery sector. Using the example of machining centres, this presentation will show the systematic procedure for verifying and validating control systems using Application Specific Integrated Circuits (ASICs) and microcomputers for safety functions. One section will describe the control structure of machining centres with control systems using “ integrated safety.” A diverse redundant architecture combined with crossmonitoring and forced dynamisation is explained. In the main section the steps of the systematic certification procedure are explained showing some results of the certification of drilling machines. Specification reviews, design reviews with test case specification, statistical analysis, and walk-throughs are the analytical measures in the testing process. Systematic tests based on the test case specification, Electro Magnetic Interference (EMI) and environmental testing, and site acceptance tests on the machines are the testing measures for validation. A complex software driven system is always undergoing modification. Most of the changes are not safety-relevant but this has to be proven. A systematic procedure for certifying software modifications is presented in the last section of the paper.