1 Scope
This part of ISO 15998 assists in the interpretation and application of the performance criteria and tests of functional safety for electronic machine control systems (MCS), used on earth-moving machinery, given in the first part of ISO 15998, by
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— illustrating an alternative method of hazard assessment,
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— providing information and application examples to illustrate compliance with ISO 15998,
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— clarifying definitions, requirements and application of ISO 15998, in addressing the risk of hazardous machine movements by safety-related MCS, and
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— providing guidance on the use and relationship of the normative references cited in the first part of ISO 15998.
Electronic MCS are those control systems that directly affect machine motion, i.e. propulsion (powered motion), braking, steering, attachments and working tool control systems. ISO 15998 is applicable to the mechanical failures of switches, sensors and other electronic devices and to the mechanical failure of solenoid valves such as sticking caused by debris (electronic fault monitoring of the solenoid valve function can be used if the risk assessment determines it is necessary).
Systems and ESAs (electrical/electronic subassemblies) that are ancillary to machine operation and which do not alter machine control — such as monitors, alarms, gauges, lights and wipers, as well as those portions of systems that provide feedback to the operator — are outside the scope of ISO 15998, as are purely hydraulic, pneumatic and/or mechanical MCS not using electronic/electric components, and mechanical failures such as broken axles, purely mechanical valves, tyres and similar.