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Proceedings Paper

Economical Fault-Tolerant Design In Medical Laser Systems
Author(s): John L. Jayne; Bruce L. Redlien
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Paper Abstract

Control system design for medical products has been greatly enhanced by the advent of microcontrollers. However, the introduction of software control has given rise to a new class of potentially hazardous, fault-intolerant situations. This paper discusses a system of hardware/software interrelationships which provide for efficient fault tolerant control system design. Medical laser systems under unsupervised, nonredundant (single) processor control are easily designed but are considered unsafe by most regulatory commissions. Redundant (multiple) processor control is considered safe but system development is complicated and hence prohibitively expensive for small scale medical systems. A nonredundant processor utilizing a software kernal and a hardware shell can be easily configured to satisfy regulatory safety requirements. Such a system retains much of the pliancy inherent in software control while adding the simplicity and reliability of hardware safety constraints. The hardware/software interaction forms a hybrid redundancy whereby the software serves to monitor the integrity of the hardware and the hardware maintains operational boundaries for the software. The initial hardware design remains fixed according to system performance requirements. Very little special software is needed to accommodate the hardware constraints and most system operational changes can be made solely via software. This results in a system design which is safe, sufficiently flexible, and economically feasible.

Paper Details

Date Published: 11 September 1989
PDF: 8 pages
Proc. SPIE 1066, Laser Surgery: Advanced Characterization, Therapeutics, and Systems, (11 September 1989); doi: 10.1117/12.952067
Show Author Affiliations
John L. Jayne, Quantronix Corporation (United States)
Bruce L. Redlien, Quantronix Corporation (United States)

Published in SPIE Proceedings Vol. 1066:
Laser Surgery: Advanced Characterization, Therapeutics, and Systems
Kazuhiko Atsumi M.D.; Norman R. Goldblatt; Stephen N. Joffe M.D., Editor(s)

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