Information and posts related to CE Marking of machinery and industrial products
Instructions are one of the basic items that users expect to get when they purchase a product, and yet these important documents are often poorly written, badly translated, and incomplete. Key product features are badly described, and information on features, settings and hazards may be absent. All of this despite the fact that the minimum requirements […]
This morning I read news of the tests that the May Government plans to use when assessing the Brexit deal they are trying to negotiate with the EU. The @CommonsEUexit report on the UK/EU future relationship has just been published. Here are its “key tests” for judging a future deal. Full text of the report here – […]
Machinery Safety Labels The third level of the Hierarchy of Controls is Information for Use. Safety Labels are a key part of the Information for Use provided by machine builders to users and are often the only information that many users get to see. This makes the design and placement of the safety labels critical to […]
Ed. Note: This article was revised 25-Jul-17 to include information on safe standstill. Safe Drive Control including STO Motor drives are everywhere. From DC variable speed drives and indexing drives, through AC Variable Frequency drives, servo drives and stepper motor drives, the capabilities and the flexibility of these electronic systems has given machine designers unprecedented […]
Fault Consideration & Fault Exclusion ISO 13849 – 1, Chapter 7 [1, 7] discusses the need for fault consideration and fault exclusion. Fault consideration is the process of examining the components and sub-systems used in the safety-related part of the control system (SRP/CS) and making a list of all the faults that could occur in each one. This a definitely non-trivial […]
CE Marking Wire and Cable In an earlier post, I wrote about the requirements for CE Marking wire and cable and discussed the <HAR> mark. In 2016, the Construction Products Regulation 305/2011 (CPR) came into effect, replacing the Construction Products Directive 89/106/EEC. The CPR included provisions covering any kind of materials that could be used in […]
What is a Common Cause Failure? There are two similar-sounding terms that people often get confused: Common Cause Failure (CCF) and Common Mode Failure. While these two types of failures sound similar, they are different. A Common Cause Failure is a failure in a system where two or more portions of the system fail at the same time from a single […]
What is Diagnostic Coverage? Understanding Diagnostic Coverage (DC) as it is used in ISO 13849 – 1 [1] is critical to analysing the design of any safety function assessed using this standard. In case you missed a previous part of the series, you can read it here. In the last instalment of this series discussing MTTFD, I brought up the […]
Functional safety is all about the likelihood of a safety system failing to operate when you need it. Understanding Mean Time to Dangerous Failure, or MTTFD, is critical. If you have been reading about this topic at all, you may notice that I am abbreviating Mean Time to Dangerous Failure with all capital letters. Using MTTFD is […]
At this point, you have completed the risk assessment, assigned required Performance Levels to each safety function, and developed the Safety Requirement Specification for each safety function. Next, you need to consider three aspects of the system design: Architectural Category, Channel Mean Time to Dangerous Failure (MTTFD), and Diagnostic Coverage (DCavg). In this part of the […]