Designed to provide developers and testers of safety-related control systemss with comprehensive support in the evaluation of safety in the context of EN ISO 13849-1, SISTEMA software is available for download at www.wielandsafety.net. SISTEMA stands for Safety Integrity Software Tool for the Evaluation of Machine Applications and enables users to model the structure of the safety-related control system components based on the designated architectures. This, in turn, enables reliability values to be calculated automatically with various levels of detail, including that of the attained Performance Level (PL).
Relevant parameters such as the risk parameters for determining the required Performance Level (PLr), the Category, measures against common-cause failures (CCFs) on multi-channel systems, the average component quality (MTTFd) and the average fault detection level (DCavg) of components and blocks are entered in forms. Once the required information has been entered into SISTEMA, the results are calculated and displayed instantly. A practical advantage for users is that any parameter change is reflected immediately on the user interface.
The time-consuming consultation of tables and calculation of formulae (calculation of the MTTFd by means of the parts count method, symmetrisation of the MTTFd for each channel, estimation of the DCavg, calculation of the PFH and PL, etc), are performed by the software. This enables users to adjust parameter values and assess the global effect of modifications with the minimum of effort. The final results are printed out in a report.
www.wielandsafety.net was launched specifically to deal with concerns regarding the recently introduced Machinery Directive 2006/42/EC and has become an increasingly popular point of reference for engineers wishing to access the latest information on machinery safety. In addition to the free SISTEMA download there are useful links and a wealth of information on products and standards.