BS EN 61703:2016

What is BS EN 61703 – Mathematical expression of dependability of control system about?  

This International Standard provides mathematical expressions for selected reliability, availability, maintainability and maintenance support measures defined in IEC 60050-192:2015. In addition, BS EN 61703 introduces some terms not covered in IEC 60050-192:2015. They are related to aspects of the system of item classes. 

According to IEC 60050-192:2015, dependability [192-01-22] is the ability of an item to perform as and when required and an item [192-01-01] can be an individual part, component, device, functional unit, equipment, subsystem, or system. 

To account for mathematical constraints, BS EN 61703 splits the items between the individual items considered as a whole (e.g., individual components) and the systems made of several individual items. BS EN 61703 provides general considerations for the mathematical expressions for systems as well as individual items but the individual items which are easier to model are analysed in more detail with regards to their repair aspects. 

Who is BS EN 61703 – Mathematical expression of dependability of control system for? 

BS EN 61703 on mathematical expressions for reliability, availability, maintainability and maintenance support is useful for: 

• Manufacturers of control system devices and components 
• Software developers of control system devices 
• Inspection teams 

Why should you use BS EN 61703 – Mathematical expression of dependability of control system?  

IEC 60050-192 provides definitions for dependability and its influencing factors, reliability, availability, maintainability and maintenance support, together with definitions of other related terms commonly used in this field. Some of these terms are measures of specific dependability characteristics, which can be expressed mathematically.  

BS EN 61703 when used in conjunction with IEC 60050-192 provides practical guidance essential for the quantification of those measures. BS EN 61703 illustrates the applicability of each dependability measure in simple examples. 

Overall, BS EN 61703 helps you to understand how the dependability of control systems is established in mathematical expressions and what it means. 

What’s changed since the last update? 

BS EN 61703:2016 replaces IEC 61703:2001. BS EN 61703:2016 includes the following significant technical changes with respect to the IEC 61703:2001: 

• Standard made as self containing as possible 
• Item split between individual items and systems

Generalization of the dependability concepts for systems made of several components:

• Introduction of the conditional failure intensity (Vesely failure rate) 
• Introduction of the state-transition and the Markovian models