No Risk, more Safety

The introduction of the new Machinery Directive 2006/42/EG will see fundamental changes take place with regard to assessing suitable safety systems. As an expert partner to the machine-building industry Weidmüller supports its customers in maintaining the new conditions.

The new directive, implemented by the Machinery Directive into German law, confronts automation suppliers and machine builders alike with the task of making a binding statement regarding the failure probability of their machinery and facilities.

Compliance with the relevant EU regulations must be proven for all products covered by the machinery definition found in the Directive. This is then documented by the CE label on the product. A significant portion of the compliance concerns machine safety and the protection of human well-being.

Weidmüller supports its customers undertaking an evaluation of the complete system by providing details of values regarding the reliability or the failure rate of the active components available from the Weidmüller spectrum of products. For modules subjected to high mechanical loads, such as relays,"B10" values are used to calculate the failure probability. These values indicate how much time is expected to elapse before ten percent of the relays in a given application will fail. Parameters such as switching current, switching voltage and circuitry are substantial factors in these calculations.

Another requirement resulting from the new Machinery Directive is the avoidance of common cause failures (CCFs) in regards to machine safety as described by the EN ISO 13849-1 standard. One suitable step is providing reliable surge voltage protection. When machine and facility engineers are able to determine that they can prevent a direct or indirect lightning strike from causing destruction, they are entitled to 15 of the 100 evaluation points in the Machinery Directive assessment scale. This already gives them almost a quarter of the 65 points need to fulfil the CCF requirement.

The Weidmüller line of components for lighting and surge protection includes protective modules for power, signal and data applications. Components such as the VARITECTOR SPC, which provides pluggable surge protection for measuring and control signals, fulfil the newest standards. The VARITECTOR SPC provides D1, C2 and C1 protection as required by IEC 61643-22. It also has an internal monitoring function that regulates error detection and alert processes. If there is a short circuit on the signal line or a connection fault, the arrester switches over to overload-outage mode as required by the latest version of IEC 61643-21. With this functionality, the VARITECTOR SPC helps to prevent the failure of other components (common cause failure).